−---
−title: Natural Stone Tile
−category: Architectural / Finishes
−toc_depth: 3
−description: >
− When to use: Interior and protected exterior natural dimension-stone tile and thin slab finishes — granite, marble, limestone, travertine, slate, quartzite, sandstone, and serpentine ("green marble") — installed on floors, walls, wainscots, stair treads, thresholds, and countertops in commercial, institutional, hospitality, retail, and high-end multi-family construction. Covers stone-type selection and the governing ASTM dimension-stone material specifications, physical-property testing (absorption, density, compressive and flexural strength, abrasion), surface finishes, slip resistance, setting-material selection including the epoxy and white-mortar requirements for moisture-sensitive and translucent stone, crack-isolation and waterproof membranes, movement-joint design, substrate flatness, sealing, and the failure modes peculiar to natural stone (efflorescence, picture-framing, warping, shade and vein variation).
− Not intended for: Manufactured ceramic, porcelain, glass, and quarry tile, including stone-look porcelain (see [[sync/ceramic-tile]]); poured and precast terrazzo (see [[sync/terrazzo]]); resilient, vinyl, and rubber flooring (see [[sync/resilient-flooring]]); polished concrete floors (see [[sync/polished-concrete]]); exterior anchored or rainscreen stone cladding and stone veneer engineered as a structural envelope component; cast stone and agglomerate/engineered "quartz" countertops; structural slab design, placement, and curing; and below-grade building-envelope waterproofing (see [[sync/below-grade-waterproofing]]).
−---
−
−# Scope
−
−This standard governs the materials and installation of natural dimension-stone tile and thin slabs — granite, marble, limestone, travertine, slate, quartzite, sandstone, and the serpentine stones commonly sold as "green marble" — set by the thin-bed, medium-bed, and thick-bed (full mortar-bed) methods on interior and protected exterior floors, walls, wainscots, stair treads, risers, thresholds, base, and countertops. Natural stone is specified where the depth, movement, and individuality of a natural material are wanted: lobbies, elevator cabs, premium restrooms, hospitality and retail floors, monumental stairs, and feature walls. Unlike a manufactured tile, every piece of natural stone is a sample of a geologic deposit; color, vein, shade, density, porosity, and even strength vary not only from lot to lot but from piece to piece within a single block, and the material's behavior in service is governed by its mineralogy. The single most important act of specifying natural stone is therefore identifying the correct stone type, its governing ASTM material specification, and the service environment, because a stone that is correct on an interior dry wall is a defect on an exterior freeze-thaw floor, and a moisture-sensitive serpentine set with an ordinary water-based mortar will curl off the substrate.
−
−A stone installation is a layered system — structural substrate, cleavage or uncoupling membrane or backer, crack-isolation or waterproof membrane where required, setting bed, stone, grout or sealant joints, and movement and perimeter joints — and the durability of the finished work is governed far more by the substrate, the setting bed, the membrane, and the movement-joint design than by the stone itself. The overwhelming majority of stone failures in the field — debonding, cracking, lippage, warping, picture-framing, staining, and efflorescence — originate in substrate movement, inadequate or wrong setting material, omitted movement joints, or moisture that was never accounted for, not in a defect of the stone. The Contractor shall treat the installation as a coordinated system, shall select a method from the TCNA Handbook for Ceramic, Glass, and Stone Tile Installation and the Natural Stone Institute Dimension Stone Design Manual appropriate to the stone, substrate, and service, shall verify that the stone, setting material, membrane, and grout are mutually compatible and approved for the specific stone, and shall not begin setting stone until the substrate has passed the flatness, soundness, and moisture acceptance criteria of this standard.
−
−Coordinate the concrete substrate, its surface finish, its curing, and the location of structural and control joints with the structural and concrete work; every structural, cold, and control joint in the substrate, and every change in substrate plane or material, shall be carried through the stone as a movement joint, and these locations are established long before stone work begins. Coordinate waterproofing of the building envelope and of wet areas with [[sync/below-grade-waterproofing]] where stone is applied over a waterproofed assembly. Coordinate transitions to adjacent finishes with [[sync/ceramic-tile]], [[sync/terrazzo]], [[sync/resilient-flooring]], and [[sync/polished-concrete]] so that thresholds, transition profiles, and finish-floor elevations reconcile.
−
−# Referenced Standards
−
−All materials, testing, and installation shall comply with the latest edition adopted by the Authority Having Jurisdiction for each of the following standards. Where the contract documents, a referenced standard, the TCNA Handbook method called out, the Natural Stone Institute Dimension Stone Design Manual, or the stone or setting-material manufacturer's or fabricator's written instructions impose a more stringent requirement than the minimum of any other standard, the more stringent requirement governs unless the Architect of Record directs otherwise in writing. For natural stone the fabricator's and setting-material manufacturer's written instructions for the specific stone are not merely advisory — a moisture-sensitive or friable stone has handling, setting, and sealing requirements that the generic standards do not capture, and disregarding them voids the installation warranty.
−
−| Standard | Title |
−|----------|-------|
−| ASTM C503 / C503M | Specification for Marble Dimension Stone |
−| ASTM C568 / C568M | Specification for Limestone Dimension Stone |
−| ASTM C615 / C615M | Specification for Granite Dimension Stone |
−| ASTM C616 / C616M | Specification for Quartz-Based (Sandstone) Dimension Stone |
−| ASTM C629 / C629M | Specification for Slate Dimension Stone |
−| ASTM C1526 | Specification for Serpentine Dimension Stone |
−| ASTM C1527 / C1527M | Specification for Travertine Dimension Stone |
−| ASTM C97 / C97M | Test Methods for Absorption and Bulk Specific Gravity of Dimension Stone |
−| ASTM C99 / C99M | Test Method for Modulus of Rupture of Dimension Stone |
−| ASTM C170 / C170M | Test Method for Compressive Strength of Dimension Stone |
−| ASTM C880 / C880M | Test Method for Flexural Strength of Dimension Stone |
−| ASTM C241 / C241M | Test Method for Abrasion Resistance of Stone Subjected to Foot Traffic |
−| ASTM C1353 / C1353M | Test Method for Abrasion Resistance of Dimension Stone Subjected to Foot Traffic Using a Rotary Platform Abraser |
−| ASTM C1028 | Test Method for Static Coefficient of Friction (superseded by ANSI A326.3 for slip resistance) |
−| ANSI A137.1 | Specifications for Ceramic Tile (referenced for tile-form stone dimensional and DCOF requirements) |
−| ANSI A108.01 / A108.02 | General Requirements and Materials, Environmental, and Workmanship for Installation of Tile |
−| ANSI A108.5 | Installation with Dry-Set or Latex-Portland Cement Mortar |
−| ANSI A108.6 | Installation with Chemical-Resistant, Water-Cleanable Tile-Setting and -Grouting Epoxy |
−| ANSI A108.13 | Installation of Load-Bearing, Bonded, Waterproof Membranes for Thin-Set Ceramic Tile and Dimension Stone |
−| ANSI A108.17 | Installation of Crack-Isolation Membranes for Thin-Set Ceramic Tile and Dimension Stone |
−| ANSI A118.1 | Dry-Set Portland Cement Mortar |
−| ANSI A118.3 | Chemical-Resistant, Water-Cleanable Tile-Setting and -Grouting Epoxy |
−| ANSI A118.4 | Modified Dry-Set Cement Mortar |
−| ANSI A118.5 | Chemical-Resistant Furan Mortars and Grouts |
−| ANSI A118.6 | Standard Cement Grouts |
−| ANSI A118.7 | High-Performance Cement Grouts |
−| ANSI A118.10 | Load-Bearing, Bonded, Waterproof Membranes for Thin-Set Installation |
−| ANSI A118.12 | Crack-Isolation Membranes for Thin-Set Installation |
−| ANSI A118.15 | Improved Modified Dry-Set Cement Mortar |
−| ANSI A326.3 | Test Method for Measuring Dynamic Coefficient of Friction of Hard-Surface Flooring Materials |
−| TCNA Handbook | TCNA Handbook for Ceramic, Glass, and Stone Tile Installation (method designations and movement-joint guideline EJ171) |
−| NSI Dimension Stone Design Manual | Natural Stone Institute Dimension Stone Design Manual |
−| IBC | International Building Code (current edition adopted by jurisdiction) |
−
−The ASTM dimension-stone material specifications (C503, C568, C615, C616, C629, C1526, C1527) are the foundation of this standard: each defines, for its stone type, the minimum physical properties — water absorption per ASTM C97, density, compressive strength per ASTM C170, modulus of rupture per ASTM C99 and flexural strength per ASTM C880, and abrasion resistance per ASTM C1353 — that a sound, durable stone must meet. The TCNA Handbook supplies the tested installation methods by designation and the movement-joint guideline EJ171, and the NSI Dimension Stone Design Manual is the recognized source for stone-specific selection, finishing, anchoring, and tolerance guidance that the tile standards do not address. Where stone is supplied in tile form (gauged, calibrated units), the dimensional and slip-resistance provisions of ANSI A137.1 and ANSI A326.3 also apply.
−
−# Submittals
−
−## Action Submittals
−
−The Contractor shall submit the following for the Architect's review prior to procurement and installation. Installation shall not begin until the stone material certification, the setting-material compatibility statement, and, where applicable, the substrate moisture report have been submitted and reviewed, because the stone type and substrate condition together determine the setting material, the membrane, the sealing requirement, and the freeze-thaw suitability.
−
−- Stone material certification reporting, for each stone, the commercial and geologic name, the quarry source, the governing ASTM specification, and the measured physical properties (absorption and density per ASTM C97, compressive strength per ASTM C170, flexural strength per ASTM C880 or modulus of rupture per ASTM C99, and abrasion resistance per ASTM C1353 for floor stone), demonstrating compliance with the governing specification
−- Product data for each setting material, membrane, grout, and accessory, identifying the governing ANSI specification and a written statement that the selected setting material, membrane, and grout are approved by their manufacturer for the specific stone and substrate and for the service condition, including an explicit statement of suitability for moisture-sensitive or translucent stone where such stone is specified
−- The TCNA Handbook method designation, or the NSI Dimension Stone Design Manual detail, proposed for each stone location, identifying the substrate, membrane, setting bed, and movement-joint treatment
−- Full-range samples and, for stone with significant directional vein or shade variation, full-size sample sets or a reviewed approved range establishing the acceptable extremes of color, vein, shade, and finish
−- Slip-resistance (DCOF) test data per ANSI A326.3 for each floor stone in its specified finish, identifying the use classification for which the value qualifies the stone
−- Shop drawings showing stone layout, setting-out and control lines, vein direction and match (book-match, slip-match, blend), the location of every movement and perimeter joint, edge and trim profiles, stair and threshold details, and slab jointing, coordinated with the [[drawing: finish plans, elevations, stone layout, and details]]
−- For slabs on or below grade and for moisture-sensitive stone, the substrate moisture test result and the basis for the membrane and setting-material selection
−- Sealer and impregnator product data with the stone manufacturer's or fabricator's confirmation of compatibility, and a statement of whether a pre-installation impregnating sealer is required
−
−```datasheet
−label: Action Submittals Required
−type: checkbox
−options:
− - "Stone material certification — name, source, ASTM spec, and measured physical properties (C97, C170, C880/C99, C1353)"
− - "Product data — setting materials, membranes, grout (ANSI designation + stone-specific compatibility statement)"
− - "TCNA method / NSI detail per location"
− - "Samples — full color/vein/shade range and approved range set"
− - "DCOF slip-resistance data per ANSI A326.3 (floor stone, specified finish)"
− - "Shop drawings — layout, vein match, movement joints, edge profiles, stair/threshold details"
− - "Substrate moisture test result (slabs on/below grade and moisture-sensitive stone)"
− - "Sealer/impregnator product data with compatibility confirmation"
−default: "Stone material certification — name, source, ASTM spec, and measured physical properties (C97, C170, C880/C99, C1353)"
−```
−
−## Closeout Submittals
−
−- Manufacturer warranty documentation for the stone, setting materials, and sealer, executed in the Owner's name where an owner-registered warranty is offered
−- Maintenance instructions describing permitted cleaning agents, the resealing interval and product, and prohibited cleaners (acidic cleaners on calcareous stone, abrasive pads on polished finishes) for each stone and finish
−- Attic-stock transmittal documenting the quantity, stone, finish, size, and block/lot of spare stone delivered to the Owner
−
−# Quality Assurance
−
−## Installer Qualifications
−
−Stone shall be installed by an installer with documented experience in commercial natural-stone installations of the specific stone type, finish, and method required. Stone work demands skills that ordinary tile work does not: matching vein and shade across a wall, setting moisture-sensitive stone with epoxy, controlling lippage on large gauged slabs, dry-laying and blending from multiple crates to distribute natural variation, and finishing field-cut edges to match factory edges. The Contractor should employ installers credentialed under a recognized industry program for stone and large-format work and shall not assign stone work — particularly moisture-sensitive, friable, polished, or large-slab stone — to labor experienced only in manufactured tile.
−
−```datasheet
−label: Installer Qualification
−type: radio
−options:
− - "Credentialed stone / large-format installer required (slabs, polished, moisture-sensitive, or any edge over 15 in)"
− - "Experienced commercial natural-stone installer"
− - "Experienced commercial tile installer (calibrated stone tile, interior dry only)"
−default: "Experienced commercial natural-stone installer"
−```
−
−## Mock-Up
−
−```datasheet
−label: Mock-Up Required
−type: radio
−options:
− - "Yes — representative area of each stone, including a movement joint, an edge/trim condition, and a wet-area or stair detail where applicable"
− - "No"
−default: "Yes — representative area of each stone, including a movement joint, an edge/trim condition, and a wet-area or stair detail where applicable"
−```
−
−Where a mock-up is required, the Contractor shall install a representative area of each stone type and finish at a location directed by the Architect, including at least one movement or perimeter joint, one edge or trim condition, one internal or external corner, one transition to an adjacent finish, and a stair, threshold, or wet-area detail where such conditions occur. For stone the mock-up is especially important because it establishes the accepted standard for the natural range of color, vein, and shade, the joint width and grout color, the lippage, the finish, and the sealer appearance; it shall remain available for comparison throughout the work. Because natural variation is intrinsic, the approved range — not a single sample — defines acceptance.
−
−## Lippage and Joint Acceptance
−
−```datasheet
−label: Maximum Allowable Lippage
−type: radio
−unit: in
−options:
− - "1/32 in plus inherent warpage (joints under 1/4 in; gauged/calibrated stone)"
− - "1/16 in plus inherent warpage (joints 1/4 in and wider)"
− - "Per ANSI A108 / NSI for the joint width, stone, and finish"
−default: "Per ANSI A108 / NSI for the joint width, stone, and finish"
−```
−
−Lippage — the difference in elevation between the edges of two adjacent units — shall not exceed the allowance of ANSI A108 and the NSI Dimension Stone Design Manual for the joint width, stone, and finish, plus any inherent warpage permitted for the stone. Lippage is more conspicuous on stone than on tile because polished and honed stone reflects light across the joint and because cleft and calibrated stone vary in thickness; it becomes more difficult to control as unit size increases and joint width decreases, which is why large slabs demand a flatter substrate and a controlled minimum joint. The grout-joint width shall not be less than the minimum the stone's dimensional and thickness variation warrants.
−
−## Pre-Installation Conference
−
−Before installation begins, the Contractor shall hold a pre-installation conference with the Architect, the stone fabricator, and the installer to review the stone type and its moisture sensitivity and friability, the substrate condition, flatness, and moisture, the TCNA method or NSI detail and the setting materials selected, the layout, vein-match, and blending plan, the movement-joint plan, the sealing requirement and sequence, and the environmental conditions in the space. Most stone disputes trace to a property of the stone or a condition of the substrate that was known but not acted upon before setting — a moisture-sensitive stone set with the wrong mortar, a translucent stone set with a gray mortar that telegraphs through, or a structural joint not carried up as a movement joint. The conference exists to surface and resolve those conditions before any stone is set.
−
−# Environmental and Service Conditions
−
−## Service Environment Classification
−
−The service environment determines the stone type and finish, the freeze-thaw suitability, the slip-resistance requirement, the membrane requirement, the setting and grouting materials, and the sealing regimen, and it shall be established for each stone location before materials are selected.
−
−```datasheet
−label: Service Environment
−type: select
−drawing_ref: true
−options:
− - "Interior dry — floors and walls not regularly wetted"
− - "Interior wet — restrooms, showers, food service, fountains"
− - "Interior heavy-duty — high-traffic lobbies, retail, transit floors"
− - "Exterior, freeze-thaw exposed — protected exterior floors, walls, and paving"
− - "Submerged / continuous-wet — pools, fountains, water features"
−default: "Interior dry — floors and walls not regularly wetted"
−```
−
−Interior dry applications tolerate the broadest range of stone and finishes. Interior wet applications require a waterproof assembly, slip-resistant floor stone, an appropriate setting material, and careful attention to efflorescence and staining in absorptive stone. Exterior and freeze-thaw applications require a dense, low-absorption stone (granite or a low-absorption quartzite or quartz-based stone) because an absorptive stone — most limestone, most marble, many travertines and slates — will spall, delaminate, or deteriorate when absorbed water freezes; calcareous stone in freeze-thaw exterior service shall be used only where the specific stone has demonstrated freeze-thaw durability. Submerged and continuous-wet service requires a non-staining, low-absorption stone, an epoxy or otherwise non-efflorescing setting system, and engineering beyond the general provisions of this standard. The Contractor shall confirm the service classification for each location from the contract documents before selecting materials.
−
−## Temperature During Installation and Cure
−
−The installation area and the substrate shall be maintained at a minimum of 50 °F (10 °C) and a maximum of 100 °F (38 °C) during installation and for the cure period required by the setting and grouting materials, typically not less than 7 days for cementitious materials before exposure to water or traffic. Cementitious mortars and grouts gain strength through hydration, which slows or stops below approximately 50 °F and which can flash-set or shrink-crack in excessive heat or direct sun; epoxy materials have a temperature window for working time and cure that is narrower still. Stone set or grouted outside the temperature window, or trafficked or wetted before cure, debonds or cracks at the bond line.
−
−```datasheet
−label: Minimum Ambient and Substrate Temperature During Installation and Cure
−type: range
−unit: °F
−options:
− min: 50
− max: 60
− step: 5
−default: 50
−```
−
−## Substrate Moisture
−
−Where stone is installed over concrete slabs on or below grade, the substrate moisture condition shall be evaluated and a bonded waterproof or vapor-managing membrane provided where moisture would otherwise drive efflorescence, staining, debonding, or warping through the assembly. Natural stone is far more vulnerable to substrate moisture than manufactured tile: residual slab moisture and alkalinity migrating up through the assembly carry mineral salts that deposit as efflorescence on and within absorptive stone, stain light and translucent stone, and — in moisture-sensitive stone — supply the water that causes warping and bond loss. Where the assembly includes moisture-sensitive stone or a moisture-sensitive membrane or adhesive, the substrate moisture shall be measured (the relative-humidity method of ASTM F2170 being the recognized measure) and the membrane and setting materials selected for the measured condition.
−
−```datasheet
−label: Substrate Moisture Management (slabs on/below grade)
−type: radio
−drawing_ref: true
−options:
− - "Bonded waterproof membrane (ANSI A118.10) over slab — wet areas, moisture-sensitive or absorptive stone"
− - "Vapor-managing / moisture-tolerant assembly with cementitious setting bed — durable non-sensitive stone only"
− - "Standard thin-set over sound dry slab — interior dry, above-grade, durable stone only"
−default: "Bonded waterproof membrane (ANSI A118.10) over slab — wet areas, moisture-sensitive or absorptive stone"
−```
−
−## Lighting for Inspection
−
−Permanent or equivalent temporary lighting shall be operating during installation and inspection so that lippage, shade and vein match, joint alignment, hollow-bonded areas, finish uniformity, and surface defects can be evaluated under realistic conditions. Polished and honed stone is highly sensitive to raking light, which exaggerates lippage and finish variation; the finished work shall be evaluated under the lighting in which it will be viewed in service, except that critical-light conditions called out in the contract documents shall be evaluated under raking light if specified.
−
−# Stone Products
−
−## Stone Type and Governing Specification
−
−The stone type and its governing ASTM specification determine the service environment, the freeze-thaw suitability, the strength, the absorption and staining behavior, the moisture sensitivity, the appropriate finishes, and the maintenance regimen. The stone type shall be selected for the use, traffic, exposure, and maintenance expectations of each space, shall be identified by both commercial and geologic name and quarry source, and shall be indicated in the [[drawing: stone schedule]].
−
−```datasheet
−label: Stone Type
−type: select
−drawing_ref: true
−options:
− - "Granite (ASTM C615) — dense igneous; floors, exterior, high-traffic, wet"
− - "Marble (ASTM C503) — calcareous metamorphic; interior floors and walls"
− - "Limestone (ASTM C568) — calcareous sedimentary; interior, protected exterior"
− - "Travertine (ASTM C1527) — porous calcareous; interior floors and walls (filled/unfilled)"
− - "Slate (ASTM C629) — fissile metamorphic; floors, treads, exterior paving"
− - "Quartzite / quartz-based sandstone (ASTM C616) — siliceous; durable floors and exterior"
− - "Serpentine 'green marble' (ASTM C1526) — moisture-sensitive; interior, epoxy-set"
−default: "Marble (ASTM C503) — calcareous metamorphic; interior floors and walls"
−```
−
−Granite, governed by ASTM C615, is a dense igneous stone with very low absorption (typically not more than about 0.40 percent) and high compressive and flexural strength; it is the most durable common stone and the default for high-traffic, wet, and exterior freeze-thaw floors. Marble (ASTM C503) is a calcareous metamorphic stone prized for its veining and polish but soft and acid-sensitive; it is an interior stone, etched by acids and beverages and abraded by heavy traffic, and most marbles are unsuitable for exterior freeze-thaw service. Limestone (ASTM C568) is a calcareous sedimentary stone classified by density into three types — low-density (Type I), medium-density (Type II), and high-density (Type III) — with absorption and strength varying widely across the classes; the density class governs where a given limestone may be used. Travertine (ASTM C1527) is a porous calcareous stone with natural voids that may be factory-filled or left unfilled; the voids must be addressed in both selection and maintenance. Slate (ASTM C629) is a fissile metamorphic stone with a natural cleft surface valued for slip resistance, though its absorption and the iron content of some slates require attention to staining and exterior durability. Quartz-based sandstone and quartzite (ASTM C616) are siliceous stones offering good durability and slip resistance. Serpentine, the "green marble" of commerce, is governed by ASTM C1526 and is the archetypal moisture-sensitive stone, addressed below.
−
−#### Each stone shall comply with its governing ASTM dimension-stone specification (C503, C568, C615, C616, C629, C1526, or C1527) and shall be certified by measured physical properties
−
−#### Stone used in exterior, freeze-thaw, or submerged service shall be a dense, low-absorption stone demonstrated to be durable in that service; calcareous stone shall not be used in freeze-thaw exterior service unless the specific stone is documented as freeze-thaw durable
−
−## Limestone Density Classification
−
−```datasheet
−label: Limestone Density Class (ASTM C568)
−type: radio
−options:
− - "Type I — low density (interior, light service)"
− - "Type II — medium density (interior floors and walls, general)"
− - "Type III — high density (high-traffic floors, protected exterior)"
− - "Not applicable — stone is not limestone"
−default: "Type II — medium density (interior floors and walls, general)"
−```
−
−Where limestone is specified, the density class of ASTM C568 shall be selected for the service, because absorption, density, compressive strength, and modulus of rupture all rise with the class. A low-density Type I limestone suited to a protected interior wall will absorb, stain, and wear unacceptably as a high-traffic floor, where a high-density Type III is required; selecting limestone without specifying the class invites the wrong stone for the use.
−
−## Physical Properties
−
−Each floor stone, and each stone in structural or exterior service, shall meet the minimum physical properties of its governing ASTM specification for absorption, density, compressive strength, flexural strength or modulus of rupture, and (for floors) abrasion resistance, verified by the test methods cited and reported in the stone certification. These properties are not interchangeable between stones and not assumable from the commercial name: two stones sold as "marble" or "quartzite" can differ by an order of magnitude in absorption and strength, and only the measured values against the governing specification establish suitability. Absorption per ASTM C97 governs staining, efflorescence, and freeze-thaw behavior; compressive strength per ASTM C170 and flexural strength per ASTM C880 (or modulus of rupture per ASTM C99) govern resistance to load and to support gaps; abrasion resistance (abrasion hardness Ha) per ASTM C1353 governs floor wear.
−
−#### Water absorption shall be determined per ASTM C97 and shall not exceed the maximum of the governing specification for the stone and class; low absorption shall be confirmed for any stone in wet or freeze-thaw service
−
−#### Compressive strength shall be determined per ASTM C170 and flexural strength per ASTM C880 (or modulus of rupture per ASTM C99), each meeting the minimum of the governing specification
−
−#### Abrasion resistance of floor stone shall be determined per ASTM C1353 and the abrasion hardness shall be appropriate to the traffic (light, moderate, or heavy commercial)
−
−```datasheet
−label: Minimum Abrasion Hardness (Ha) for Floor Stone (ASTM C1353)
−type: select
−options:
− - "Ha 10 — light residential / very light commercial"
− - "Ha 12 — moderate commercial floor traffic"
− - "Ha 15 — heavy commercial / institutional floor traffic"
− - "Per governing ASTM specification for the stone"
−default: "Per governing ASTM specification for the stone"
−```
−
−## Stone Form and Thickness
−
−```datasheet
−label: Stone Form
−type: select
−drawing_ref: true
−options:
− - "Gauged / calibrated stone tile — uniform thickness, thin-bed set"
− - "Cleft-finish tile (slate, quartzite) — variable thickness"
− - "Cut-to-size dimension stone — fabricator-cut to plan"
− - "Thin slab — large-format gauged slab"
− - "As scheduled"
−default: "Gauged / calibrated stone tile — uniform thickness, thin-bed set"
−```
−
−```datasheet
−label: Nominal Stone Thickness
−type: range
−unit: in
−drawing_ref: true
−options:
− min: 0.375
− max: 0.75
− step: 0.125
− setpoints: [0.375, 0.5, 0.625, 0.75]
−default: 0.375
−```
−
−The stone form and thickness determine the setting method, the substrate flatness requirement, the handling, and the joint and lippage control. Gauged (calibrated) stone tile of uniform thickness is set by the thin-bed method like manufactured tile; cleft-finish stone such as slate varies in thickness and is set by a medium-bed or full mortar-bed method that accommodates the variation, because forcing variable-thickness cleft stone into a thin-bed produces severe lippage. Floor stone thinner than the stone's strength warrants will crack over any support gap; the thickness shall be coordinated with the stone strength, the span and support, and the anticipated load, and indicated in the [[drawing: stone schedule and details]].
−
−## Surface Finish
−
−```datasheet
−label: Surface Finish
−type: select
−drawing_ref: true
−options:
− - "Polished — high gloss (interior walls, low-traffic floors, countertops)"
− - "Honed — smooth matte (interior floors and walls, general)"
− - "Flamed (thermal) — coarse slip-resistant (granite floors, exterior)"
− - "Brushed / antiqued — textured low-sheen"
− - "Sandblasted — uniform matte texture"
− - "Cleft (natural split) — slate and quartzite"
− - "Tumbled — softened edges and surface"
−default: "Honed — smooth matte (interior floors and walls, general)"
−```
−
−The finish affects appearance, slip resistance, cleanability, maintenance, and durability. A polished finish maximizes color and reflectivity but minimizes slip resistance, shows etch and wear readily on soft stone, and is generally unsuited to wet floors and high-traffic circulation; it is best reserved for walls, countertops, and low-traffic feature floors. A honed finish is the general-purpose floor and wall finish, offering better slip resistance and concealing wear better than polish. Flamed (thermal) and brushed finishes texture the surface for slip resistance and are the standard for granite floors, stair treads, and exterior paving. Cleft finishes occur naturally on slate and some quartzite and provide inherent slip resistance. The finish shall be selected for the stone, the service, and the slip-resistance requirement, and shall be consistent with the approved mock-up.
−
−#### Polished finishes shall not be used on wet floors or sloped surfaces where the slip-resistance requirement cannot be met
−
−## Slip Resistance
−
−```datasheet
−label: Dynamic Coefficient of Friction (ANSI A326.3)
−type: range
−unit: DCOF
−options:
− min: 0.42
− max: 0.60
− step: 0.01
− setpoints: [0.42, 0.50, 0.60]
−default: 0.42
−```
−
−The dynamic coefficient of friction of floor stone in its specified finish shall be measured per ANSI A326.3 and shall meet the minimum for the applicable use classification. A minimum DCOF of 0.42 applies to a level interior floor intended to be walked upon when wet; wetter, sloped, and more demanding classifications require higher values, and the result is meaningful only for the use classification under which it was reported. Slip resistance is a property of the finished stone surface as installed and maintained — a polish, a film-forming sealer, or worn or contaminated conditions change it — and the value alone does not predict whether a slip will occur; it provides a comparative basis for selecting a finish appropriate to the wet, sloped, or contaminated condition. Ramps, shower floors, pool decks, entries subject to tracked-in water, and stair treads require classification-specific values and a textured finish and shall not be defaulted to the level-interior-wet minimum.
−
−# Setting Materials
−
−## Setting Method
−
−```datasheet
−label: Setting Method
−type: select
−drawing_ref: true
−options:
− - "Thin-bed (thin-set) — gauged stone over a flat, sound substrate"
− - "Medium-bed mortar — large units and slightly variable thickness, sloped floors"
− - "Thick-bed (full mortar bed) — variable-thickness cleft stone, leveling required, exterior"
−default: "Thin-bed (thin-set) — gauged stone over a flat, sound substrate"
−```
−
−The setting method shall match the stone form, the substrate flatness, and the service. The thin-bed method bonds gauged stone to a flat substrate with a notched-trowel mortar and is the standard for calibrated stone tile. The medium-bed method uses a mortar formulated to be applied in a thicker bed without excessive shrinkage and is appropriate for large units and modest thickness variation. The thick-bed (full mortar-bed) method places the stone on a thick Portland-cement mortar bed that accommodates variable-thickness cleft stone, establishes slope to drains, and isolates the stone from substrate irregularity; it remains the most robust method for cleft slate, sloped wet-area floors, and demanding exterior work. The method shall be drawn from the TCNA Handbook or NSI Dimension Stone Design Manual and shown on the [[drawing: details]].
−
−## Bonding Mortar Type
−
−The bonding mortar shall be selected for the stone type, the substrate, and the service, shall comply with the governing ANSI A118 specification, and shall be approved by its manufacturer for the specific stone. Mortar selection for stone is not interchangeable with tile practice: the stone's moisture sensitivity, translucency, and the staining risk from the mortar itself all govern the choice, and the wrong mortar produces warping, picture-framing, or staining that no later remedy can fully correct.
−
−```datasheet
−label: Bonding Mortar Type
−type: select
−drawing_ref: true
−options:
− - "Modified dry-set cement mortar (ANSI A118.4) — general durable stone, floors and walls"
− - "Improved modified dry-set cement mortar (ANSI A118.15) — large units, slabs, demanding bond"
− - "Epoxy mortar (ANSI A118.3) — moisture-sensitive stone, chemical exposure, maximum bond"
− - "Dry-set cement mortar (ANSI A118.1) — absorptive stone over a cured mortar bed"
−default: "Modified dry-set cement mortar (ANSI A118.4) — general durable stone, floors and walls"
−```
−
−Modified dry-set cement mortar conforming to ANSI A118.4 is the default for the majority of durable, non-sensitive stone on floors and walls. Improved modified dry-set mortar conforming to ANSI A118.15 provides the higher bond, non-sag, and coverage characteristics needed for large units, slabs, and demanding vertical work. Epoxy mortar conforming to ANSI A118.3 is required for moisture-sensitive stone (see below), for chemical-exposure environments, and where the maximum bond strength is needed. Unmodified dry-set mortar conforming to ANSI A118.1 is appropriate only for absorptive stone over a cured Portland-cement mortar bed. Where a fast-setting or rapid-cure mortar is needed, it shall be a product the stone manufacturer approves for the stone, because some rapid-set mortars develop heat or alkalinity that stains sensitive stone.
−
−#### Bonding mortar shall comply with the governing ANSI A118 specification and shall be approved by its manufacturer for the specific stone and substrate
−
−## Moisture-Sensitive Stone
−
−```datasheet
−label: Moisture-Sensitive Stone Setting Requirement
−type: radio
−options:
− - "Epoxy mortar (ANSI A118.3) with 100% coverage — required for serpentine 'green marble' and other moisture-sensitive stone"
− - "Manufacturer-approved non-water setting system for the specific sensitive stone"
− - "Not applicable — stone is not moisture-sensitive"
−default: "Not applicable — stone is not moisture-sensitive"
−```
−
−Moisture-sensitive stone — chiefly serpentine "green marble," and certain marbles, slates, and resin-backed stones identified by the fabricator — shall be set only with an epoxy mortar conforming to ANSI A118.3, or another non-water-bearing system the stone manufacturer approves, applied to achieve full (100 percent) coverage. Moisture-sensitive stone absorbs water from a water-based cement or latex mortar and warps, curling its edges away from the substrate as it cures and destroying the bond; because epoxy mortar contains no water, it sets these stones without driving the warping. Full coverage is required so no joint or edge is left to absorb water or to leave an unsupported edge. The Contractor shall confirm with the fabricator whether each stone is moisture-sensitive before selecting a mortar and shall not set a moisture-sensitive stone with any water-bearing cement or latex mortar under any circumstances.
−
−#### Moisture-sensitive stone shall be set only with epoxy mortar or a manufacturer-approved non-water-bearing system, with full coverage, and shall never be set with a water-bearing cement or latex mortar
−
−## White Mortar for Translucent and Light Stone
−
−```datasheet
−label: Mortar Color for Translucent / Light Stone
−type: radio
−options:
− - "White-pigmented setting mortar required — translucent, white, and light-colored stone"
− - "Standard (gray) mortar acceptable — opaque, dark, or dense stone"
−default: "White-pigmented setting mortar required — translucent, white, and light-colored stone"
−```
−
−White marble, onyx, light limestone, and other translucent or light-colored stone shall be set with a white-pigmented setting mortar. A gray cement mortar shows through a translucent or thin light stone and shadows or darkens its appearance unevenly — a defect known as telegraphing or shadowing that cannot be corrected after setting; only a white mortar preserves the true color of the stone. The Contractor shall verify the stone's translucency on the mock-up and select the mortar color accordingly.
−
−#### Translucent, white, and light-colored stone shall be set with a white-pigmented mortar to prevent shadowing of the stone color
−
−## Crack-Isolation Membrane
−
−```datasheet
−label: Crack-Isolation Membrane (ANSI A118.12)
−type: radio
−drawing_ref: true
−options:
− - "Required over the full floor — concrete subject to shrinkage cracking or minor in-plane movement"
− - "Required at existing cracks and joints only (spot membrane)"
− - "Not required — substrate sound and not subject to in-plane cracking"
−default: "Required at existing cracks and joints only (spot membrane)"
−```
−
−A crack-isolation membrane conforming to ANSI A118.12 and installed per ANSI A108.17 shall be provided where the substrate is subject to minor in-plane movement or shrinkage cracking that would otherwise telegraph through and crack the stone. A crack in a concrete substrate transmits directly into bonded stone unless a crack-isolation membrane uncouples the stone from that movement. A crack-isolation membrane addresses minor in-plane movement only; it does not substitute for the movement joints required by EJ171, and it does not bridge structural or moving joints, which shall be carried through the stone as movement joints regardless of any membrane.
−
−## Waterproof Membrane
−
−```datasheet
−label: Waterproof Membrane (ANSI A118.10)
−type: radio
−drawing_ref: true
−options:
− - "Required — showers, wet areas, exterior, and over occupied space"
− - "Required at shower receptors and pans only"
− - "Not required — interior dry application"
−default: "Required — showers, wet areas, exterior, and over occupied space"
−```
−
−A load-bearing bonded waterproof membrane conforming to ANSI A118.10 and installed per ANSI A108.13 shall be provided in showers, steam rooms, wet areas, exterior installations, and any stone assembly over occupied or moisture-sensitive space. Stone and cementitious joints are not waterproof — water passes through joints and through absorptive stone over time — and a continuous bonded waterproof membrane is what keeps water out of the structure and limits the moisture that drives efflorescence and staining in the stone above it. Many ANSI A118.10 membranes also satisfy the crack-isolation requirements of A118.12; where a single membrane is selected for both functions, the Contractor shall verify it is certified to both standards.
−
−# Joint Materials
−
−## Grout and Pointing
−
−```datasheet
−label: Joint Filler
−type: select
−drawing_ref: true
−options:
− - "High-performance cement grout (ANSI A118.7) — general stone floors and walls"
− - "Standard cement grout (ANSI A118.6) — interior light-duty"
− - "Epoxy grout (ANSI A118.3) — chemical exposure, food service, maximum stain resistance"
− - "Unsanded cement grout — narrow joints in polished stone (prevents scratching)"
−default: "High-performance cement grout (ANSI A118.7) — general stone floors and walls"
−```
−
−The joint filler shall be selected for the joint width, the stone finish, the service, and the stain- and chemical-resistance requirement, and shall comply with the governing ANSI specification. High-performance cement grout conforming to ANSI A118.7 is the general default for stone floors and walls. Epoxy grout conforming to ANSI A118.3 is used where chemical resistance, maximum stain resistance, or a non-absorptive joint is required. For narrow joints in polished stone, an unsanded grout shall be used because the sand in a sanded grout scratches a polished surface during tooling and cleaning. Grout containing pigments or aggressive constituents that could stain a sensitive or absorptive stone shall not be used without the stone manufacturer's confirmation; pre-sealing the stone before grouting is required where the stone would otherwise absorb grout pigment.
−
−#### Unsanded grout shall be used in narrow joints of polished stone to prevent scratching of the finish
−
−#### Absorptive and sensitive stone shall be pre-sealed before grouting where the grout would otherwise stain the stone
−
−## Grout Joint Width
−
−```datasheet
−label: Grout Joint Width
−type: range
−unit: in
−drawing_ref: true
−options:
− min: 0.0625
− max: 0.375
− setpoints: [0.0625, 0.125, 0.1875, 0.25, 0.375]
−default: 0.125
−```
−
−The joint width shall be selected for the stone size, edge type, and thickness variation, and shall not be less than the minimum the stone's dimensional variation warrants. Gauged stone with a precise edge can take a narrow joint; cleft and tumbled stone with irregular edges requires a wider joint to accommodate the variation. Running a joint narrower than the stone's dimensional and thickness variation produces visible lippage and uneven joints. The joint width shall be shown in the [[drawing: stone schedule and details]].
−
−# Movement Joints
−
−## Movement Joint Design
−
−Movement joints shall be provided throughout stone work in accordance with the TCNA movement-joint guideline EJ171, and their locations shall be shown on the [[drawing: stone shop drawings and details]] before any stone is set. Movement joints are open, sealant-filled, or preformed-profile joints — not grout — that allow the stone assembly to expand, contract, and accommodate substrate movement without building the compressive stress that causes stone to tent, debond, and crack. EJ171 requires movement joints at the perimeter of every stone area where it abuts restraining surfaces, over every structural, cold, and control joint in the substrate, at changes in substrate plane or material, at internal corners, and in the field at the spacing the guideline establishes for the exposure. Omitting field movement joints in a large floor is a leading cause of catastrophic failure; thermal and moisture expansion with no place to go lifts the stone off the floor in a ridge. Grout is rigid and does not function as a movement joint; a joint intended to move shall be left open of grout and filled with the specified sealant or fitted with a preformed movement-joint profile.
−
−```datasheet
−label: Field Movement Joint Spacing — Interior
−type: range
−unit: ft
−drawing_ref: true
−options:
− min: 20
− max: 25
− step: 1
− setpoints: [20, 25]
−default: 25
−```
−
−```datasheet
−label: Field Movement Joint Spacing — Exterior or Sunlight/Moisture Exposed
−type: range
−unit: ft
−drawing_ref: true
−options:
− min: 8
− max: 12
− step: 1
− setpoints: [8, 12]
−default: 12
−```
−
−Interior field movement joints shall be provided at the spacing EJ171 establishes for interior conditions, commonly on the order of 20 to 25 feet in each direction. Exterior installations, and interior installations exposed to direct sunlight or to moisture and wide temperature swings, shall have field movement joints at substantially closer spacing, commonly on the order of 8 to 12 feet in each direction, because the larger thermal and moisture movement of an exposed assembly builds destructive stress over a shorter run. The closer of the EJ171 requirement and any project-specific requirement governs.
−
−#### Perimeter movement joints shall be provided where stone abuts restraining surfaces, walls, columns, curbs, and dissimilar floors
−
−#### Movement joints shall be carried through over every structural, cold, and control joint in the substrate and at every change in substrate plane or material
−
−#### Movement joints shall be left open of grout and filled with the specified sealant or fitted with a preformed movement-joint profile
−
−## Movement Joint Filler
−
−```datasheet
−label: Movement Joint Filler
−type: radio
−drawing_ref: true
−options:
− - "Field-applied elastomeric sealant over backer rod / bond breaker"
− - "Preformed metal or rigid movement-joint profile"
− - "Preformed flexible movement-joint profile"
−default: "Field-applied elastomeric sealant over backer rod / bond breaker"
−```
−
−Movement joints shall be filled with an elastomeric sealant of the type and color specified, installed over a backer rod or bond breaker so the sealant adheres only to the two joint faces and can stretch and compress, or shall be fitted with a preformed movement-joint profile suited to the traffic and exposure. The sealant shall be a non-staining sealant compatible with the stone — many common sealants bleed plasticizers that stain absorptive stone at the joint edge, so a sealant tested non-staining on the specific stone shall be used. The sealant or profile shall be capable of the movement the joint will see.
−
−#### Movement-joint sealant in contact with absorptive stone shall be a non-staining sealant verified compatible with the specific stone
−
−# Substrate Preparation
−
−## General Substrate Requirements
−
−The substrate shall be structurally sound, clean, dimensionally stable, and free of dust, paint, oil, grease, curing and sealing compounds, sealers, laitance, efflorescence, and any other bond-inhibiting substance. Concrete substrates shall be fully cured and shall present an open, absorptive surface; troweled-smooth, sealed, or curing-compound-treated concrete shall be mechanically abraded or shot-blasted to an open profile before stone is set, because the setting mortar bonds mechanically and cannot grip a sealed or contaminated surface. The condition of the substrate is the Contractor's responsibility to verify before installation; setting stone over a noncompliant substrate transfers a known defect into the finished work.
−
−## Flatness Tolerance
−
−```datasheet
−label: Substrate Flatness Tolerance
−type: radio
−unit: in
−options:
− - "1/4 in in 10 ft and 1/16 in in 1 ft (gauged stone with all edges under 15 in)"
− - "1/8 in in 10 ft and 1/16 in in 2 ft (large units and slabs, any edge 15 in and over)"
− - "Per the requirement for the stone size, form, and method"
−default: "Per the requirement for the stone size, form, and method"
−```
−
−The substrate shall meet the flatness tolerance required for the stone size, form, and method. For gauged stone with all edges under 15 inches the recognized tolerance is a maximum of 1/4 inch in 10 feet and 1/16 inch in 1 foot; for large units and slabs with any edge 15 inches and over the tolerance tightens to a maximum of 1/8 inch in 10 feet and 1/16 inch in 2 feet, because a large rigid unit cannot conform to and will rock on a substrate undulation that a small unit would tolerate. High spots shall be ground down and low spots filled with a cementitious patching or self-leveling underlayment compatible with the setting system. Setting large units or slabs over a substrate held only to the small-format tolerance is a common cause of lippage and hollow-bonded floors. Where cleft variable-thickness stone is set by the thick-bed method, the mortar bed accommodates substrate variation, but the finished stone surface shall still meet the flatness and lippage tolerances of this standard.
−
−## Substrate Type Verification
−
−```datasheet
−label: Substrate Type
−type: select
−drawing_ref: true
−options:
− - "Concrete slab — cured, sound, profiled"
− - "Cementitious backer unit over framing — walls and floors"
− - "Cured Portland cement mortar bed (thick-bed)"
− - "Existing sound tile / terrazzo (bond-coat or membrane over)"
−default: "Concrete slab — cured, sound, profiled"
−```
−
−The setting system and method shall match the substrate type. Stone over wood-framed floors requires a structurally adequate, stiff floor and an appropriate backer board or uncoupling/crack-isolation membrane rated for the stone and the floor's deflection, because wood expands, contracts, and deflects with moisture and load and will crack stone bonded directly to it; heavy or large stone over wood framing requires verification that the floor deflection is within the limit the stone tolerates. Stone shall not be set over a deflecting floor regardless of the mortar.
−
−# Installation
−
−## Layout and Blending
−
−The Contractor shall establish the layout from the control lines and setting-out points shown on the [[drawing: finish plan and stone layout]] so that border and cut units are balanced and of adequate width, full units fall at the most prominent locations, vein and pattern align and match as the design requires, and movement joints fall where the design and EJ171 require. Because natural stone varies, the Contractor shall dry-lay and blend the stone from several crates at once, distributing the natural range of color, vein, and shade across the work so that no concentration of dark, light, or heavily veined pieces forms a blotch, and shall obtain the Architect's approval of the dry-laid blend and vein match before setting. Layout and blending shall be completed and approved before any mortar is spread.
−
−```datasheet
−label: Vein / Pattern Match
−type: select
−drawing_ref: true
−options:
− - "Blend / random — distribute natural variation evenly"
− - "Book-match — mirror-matched adjacent slabs"
− - "Slip-match (side-slide) — repeating vein run"
− - "Vein-directional — consistent vein direction"
− - "As detailed on drawings"
−default: "Blend / random — distribute natural variation evenly"
−```
−
−Where book-match, slip-match, or directional veining is specified, the stone shall be sequenced and oriented to achieve the match shown on the shop drawings, and the fabricator's numbered layout shall be followed. Book-matched and directional work is unforgiving — a single piece set out of sequence or rotated breaks the pattern — and is the reason approved, numbered shop drawings and crate sequencing are required.
−
−## Mortar Application and Coverage
−
−Bonding mortar shall be applied with the trowel notch, technique, and open time the mortar and stone require, combed in one direction with directional troweling, and the stone set with a slight perpendicular movement to collapse the ridges and eliminate voids. The mortar coverage achieved beneath the stone shall be not less than 80 percent for interior dry applications and not less than 95 percent for exterior, wet, and heavy-load applications, with full coverage at edges and corners and no voids beneath; moisture-sensitive stone shall achieve full (100 percent) coverage. Inadequate coverage is a leading cause of stone cracking, debonding, and hollow floors — a stone bridging a void fractures under load, and an edge void admits water and lets the edge break away. Large units, slabs, and all floor stone shall be back-buttered in addition to combing the substrate, because the required coverage cannot reliably be achieved on a large or floor unit by combing the substrate alone.
−
−```datasheet
−label: Minimum Mortar Coverage Beneath Stone
−type: radio
−unit: %
−options:
− - "80% — interior dry floors and walls (durable stone)"
− - "95% — exterior, wet areas, and heavy/rolling-load floors"
− - "100% — moisture-sensitive stone (epoxy-set)"
−default: "95% — exterior, wet areas, and heavy/rolling-load floors"
−```
−
−#### Floor stone, large units, and slabs shall be back-buttered in addition to combing the substrate to achieve the required coverage
−
−#### Stone shall be set with full mortar coverage at all edges and corners and with no voids beneath, verified by periodic removal and inspection of set stone
−
−## Beating-In and Lippage Control
−
−Floor stone shall be beaten in or rolled with a beating block or the manufacturer's tool, and large units and slabs shall be set with a mechanical lippage-control (leveling) system where required, to seat the stone fully into the mortar, collapse the ridges, and bring adjacent edges into plane within the lippage allowance. Polished and honed stone makes lippage conspicuous under reflected light, so the lippage tolerance is tighter and the leveling discipline more important than for textured tile.
−
−## Grouting and Pointing
−
−Grouting shall not begin until the bonding mortar has cured for the period the mortar manufacturer requires, typically not less than 24 to 72 hours. Absorptive and sensitive stone shall be sealed with an impregnating sealer before grouting where the grout would otherwise stain the stone face. Joints shall be cleaned of mortar and debris to a uniform depth, the grout worked fully into the joints to fill them solid, the excess struck off, and the surface cleaned promptly to remove grout residue before it cures onto the stone. For polished stone, an unsanded grout shall be used and the cleaning performed before any abrasive residue can scratch the finish. Joints intended to function as movement joints shall be left open of grout.
−
−#### Grouting shall not begin until the bonding mortar has cured for the period the mortar manufacturer requires
−
−#### Movement joints shall be left open of grout and shall not be filled with grout under any circumstances
−
−## Curing and Protection
−
−The completed stone shall be protected from traffic and from other trades during the cure period and shall not be exposed to water, washing, or traffic until the setting and grouting materials have cured for the period they require, typically not less than 7 days for cementitious materials. Floors shall be protected with a breathable covering that does not trap moisture against the stone, does not transfer color or adhesive, and does not stain the stone — many common protective films and tapes stain absorptive and polished stone, so only products verified non-staining on the specific stone shall be placed in contact with it. Heavy construction traffic, rolling loads, and point loads shall be kept off the floor until cure is complete.
−
−#### Protective coverings and tapes in contact with stone shall be verified non-staining for the specific stone
−
−# Field Testing and Inspection
−
−## Bond and Installation Inspection
−
−After installation and cure, the stone shall be inspected for full bond, with no hollow-sounding (unbonded) units, no lippage exceeding the allowance, no cracked, chipped, or warped units, uniform joints fully packed and free of voids, correct vein match and shade blend, the specified finish uniform and free of scratches and grout residue, and movement joints correctly formed and left open of grout, under the permanent or equivalent lighting. Stone shall be sounded — tapped to detect the hollow ring of an unbonded unit — across the floor; hollow or unbonded units shall be removed and reset. The Contractor shall confirm by periodic removal of set stone that the required mortar coverage was achieved across the work.
−
−```datasheet
−label: Post-Installation Inspection Required
−type: radio
−options:
− - "Yes — full-area sounding and visual inspection under permanent lighting"
− - "No"
−default: "Yes — full-area sounding and visual inspection under permanent lighting"
−```
−
−## Stone Property Verification
−
−Where required by the contract documents or where the stone source is unverified, samples of the supplied stone shall be tested by an independent laboratory for the physical properties of the governing ASTM specification (absorption per ASTM C97, compressive strength per ASTM C170, flexural strength per ASTM C880 or modulus of rupture per ASTM C99, and abrasion per ASTM C1353 for floor stone) to confirm that the delivered stone meets the certified values. Stone is a natural material whose properties vary across a quarry; verification testing of the actual supplied lot guards against substitution of a weaker or more absorptive stone than was certified.
−
−```datasheet
−label: Independent Stone Property Verification
−type: radio
−options:
− - "Required — test supplied lot against governing ASTM specification"
− - "Not required — manufacturer certification accepted"
−default: "Not required — manufacturer certification accepted"
−```
−
−# Cleaning, Sealing, and Protection
−
−## Cleaning
−
−After cure, the stone shall be cleaned of grout residue, construction soil, and marks using only cleaners the stone manufacturer permits for the specific stone and finish. Acidic cleaners shall not be used on calcareous stone (marble, limestone, travertine, serpentine) because acids etch and dissolve the surface, dulling polish and pitting the stone; abrasive pads and powders shall not be used on polished finishes because they scratch the surface. The permitted cleaners and the prohibited cleaners for each stone shall be recorded in the maintenance instructions.
−
−#### Acidic cleaners shall not be used on calcareous stone (marble, limestone, travertine, serpentine)
−
−## Sealing
−
−```datasheet
−label: Sealer / Impregnator
−type: select
−options:
− - "Penetrating impregnating sealer — absorptive interior stone (marble, limestone, travertine, slate)"
− - "Penetrating sealer rated for wet / exterior service"
− - "Pre-grout impregnating sealer plus final sealer — stain-prone absorptive stone"
− - "No sealer — dense low-absorption stone (most granite, dense quartzite) where not required"
−default: "Penetrating impregnating sealer — absorptive interior stone (marble, limestone, travertine, slate)"
−```
−
−Absorptive stone shall be sealed with a penetrating impregnating sealer compatible with the stone and finish, applied after the stone and grout have cured for the period the products require, to reduce absorption, staining, and etching susceptibility. A penetrating impregnating sealer is preferred over a film-forming (topical) sealer for floors because a topical film wears unevenly, can reduce slip resistance, and traps moisture in the stone; film-forming sealers shall be used only where the manufacturer recommends them for the specific stone and finish. Stain-prone absorptive stone may require a pre-grout sealer to prevent grout staining in addition to the final sealer. Sealing is part of the maintenance basis: the sealer, the resealing interval, and the application method shall be documented in the maintenance instructions, and dense low-absorption stone that does not benefit from sealing need not be sealed.
−
−#### Sealer shall be a penetrating impregnating type compatible with the stone and finish; film-forming sealers shall be used only where the manufacturer recommends them for the specific stone
−
−# Delivery, Storage, and Handling
−
−Stone, setting materials, grout, membranes, sealers, and accessories shall be delivered in the manufacturer's original packaging with labels and crate markings intact, identifying stone, finish, size, and block/lot. Stone shall be stored indoors where practicable, protected from weather, freezing, staining, and breakage, and kept off the ground on non-staining dunnage; cardboard, wood, and adhesives that stain absorptive stone when wet shall be kept from contact with the stone faces. Cementitious setting materials and grout shall be stored dry and off the floor, and material that has hardened or exceeded its shelf life shall be discarded; epoxy and polymer components have a limited shelf life and a storage-temperature window. Slabs shall be transported, stored, and handled in A-frames and moved with the clamps and frames the fabricator requires, because an unsupported slab cracks under its own weight. All stone for a continuous area should be from the same block or lot wherever possible, because color, vein, and shade vary between blocks and a block change within a single visual field is apparent.
−
−# Warranty
−
−```datasheet
−label: Stone and Setting-Material Manufacturer Warranty Period
−type: select
−unit: years
−options:
− - "1 year (materials)"
− - "As offered by the manufacturer for the products specified"
−default: "As offered by the manufacturer for the products specified"
−```
−
−The stone supplier and setting-material manufacturers shall warrant their products against manufacturing and material defects for the period offered, and where a setting-material manufacturer offers an owner-registered system warranty covering the membrane, mortar, and grout as an installed system, that warranty should be obtained and executed in the Owner's name. The Contractor shall warrant the installation — including substrate preparation, membrane and mortar selection and application, mortar coverage, vein match and shade blend, lippage and joint quality, grouting, movement-joint formation, and sealing — against defective workmanship for the project warranty period.
−
−```datasheet
−label: Installation Workmanship Warranty Period
−type: select
−options:
− - "1 year from substantial completion"
− - "2 years from substantial completion"
−default: "1 year from substantial completion"
−```
−
−The Contractor shall be aware that manufacturer system warranties are typically void unless the complete tested system was installed in accordance with the manufacturer's instructions and the cited TCNA method or NSI detail — including the epoxy and white-mortar requirements for moisture-sensitive and translucent stone — and that the installation record is part of the warranty basis. Failures arising from substrate movement at locations where required movement joints were omitted, from warping of moisture-sensitive stone set with a water-bearing mortar, from water intrusion where a required waterproof membrane was omitted, from staining or etching due to cleaning or sealing contrary to the manufacturer's instructions, or from loads exceeding the rated service are excluded from both warranties. Because natural stone varies, variation in color, vein, and shade within the approved range is an inherent characteristic of the material and not a defect.
−
−# Spare and Extra Materials
−
−```datasheet
−label: Attic Stock Quantity
−type: range
−unit: % of installed area
−options:
− min: 2
− max: 5
− step: 1
−default: 3
−```
−
−The Contractor shall deliver to the Owner spare stone of each type, finish, and size installed, in the percentage of installed area stated, in full crates labeled with the stone, finish, size, and block/lot. Attic stock from the same block or lot is especially important for natural stone because later-quarried replacement stone will differ in color, vein, and shade and cannot be matched; the spare material allows the Owner to repair damage with stone that matches the original installation. Spare stone shall be stored by the Owner in a dry, protected location on non-staining dunnage.
+---
+title: Natural Stone Tile
+category: Architectural / Finishes
+toc_depth: 3
+description: >
+ When to use: Interior and protected exterior natural dimension-stone tile and thin slab finishes — granite, marble, limestone, travertine, slate, quartzite, sandstone, and serpentine ("green marble") — installed on floors, walls, wainscots, stair treads, thresholds, and countertops in commercial, institutional, hospitality, retail, and high-end multi-family construction. Covers stone-type selection and the governing ASTM dimension-stone material specifications, physical-property testing (absorption, density, compressive and flexural strength, abrasion), surface finishes, slip resistance, setting-material selection including the epoxy and white-mortar requirements for moisture-sensitive and translucent stone, crack-isolation and waterproof membranes, movement-joint design, substrate flatness, sealing, and the failure modes peculiar to natural stone (efflorescence, picture-framing, warping, shade and vein variation).
+ Not intended for: Manufactured ceramic, porcelain, glass, and quarry tile, including stone-look porcelain (see [[sync/ceramic-tile]]); poured and precast terrazzo (see [[sync/terrazzo]]); resilient, vinyl, and rubber flooring (see [[sync/resilient-flooring]]); polished concrete floors (see [[sync/polished-concrete]]); exterior anchored or rainscreen stone cladding and stone veneer engineered as a structural envelope component; cast stone and agglomerate/engineered "quartz" countertops; structural slab design, placement, and curing; and below-grade building-envelope waterproofing (see [[sync/below-grade-waterproofing]]).
+---
+
+# Scope {toc}
+
+## This standard governs the materials and installation of natural dimension-stone tile and thin slabs — granite, marble, limestone, travertine, slate, quartzite, sandstone, and the serpentine stones commonly sold as "green marble" — set by the thin-bed, medium-bed, and thick-bed (full mortar-bed) methods on interior and protected exterior floors, walls, wainscots, stair treads, risers, thresholds, base, and countertops. {note}
+
+## The Contractor shall treat the installation as a coordinated system.
+## The Contractor shall select a method from the TCNA Handbook for Ceramic, Glass, and Stone Tile Installation and the Natural Stone Institute Dimension Stone Design Manual appropriate to the stone, substrate, and service.
+## The Contractor shall verify that the stone, setting material, membrane, and grout are mutually compatible and approved for the specific stone.
+## The Contractor shall not begin setting stone until the substrate has passed the flatness, soundness, and moisture acceptance criteria of this standard.
+## The Contractor shall coordinate the concrete substrate, its surface finish, its curing, and the location of structural and control joints with the structural and concrete work, so that every structural, cold, and control joint in the substrate and every change in substrate plane or material is carried through the stone as a movement joint.
+## The Contractor shall coordinate waterproofing of the building envelope and of wet areas with [[sync/below-grade-waterproofing]] where stone is applied over a waterproofed assembly.
+## The Contractor shall coordinate transitions to adjacent finishes with [[sync/ceramic-tile]], [[sync/terrazzo]], [[sync/resilient-flooring]], and [[sync/polished-concrete]] so that thresholds, transition profiles, and finish-floor elevations reconcile.
+## Natural stone is specified where the depth, movement, and individuality of a natural material are wanted, and because every piece is a sample of a geologic deposit whose color, vein, shade, density, porosity, and strength vary from piece to piece, the correct stone type, its governing ASTM material specification, and the service environment are the most important things to identify. {note}
+## A stone installation is a layered system whose durability is governed far more by the substrate, setting bed, membrane, and movement-joint design than by the stone itself, and the majority of field failures originate in substrate movement, wrong setting material, omitted movement joints, or unaccounted-for moisture rather than in a defect of the stone. {note}
+
+# Referenced Standards {toc}
+
+## The following standards are referenced in this document. {note}
+
+| Standard | Title |
+|----------|-------|
+| ASTM C503 / C503M | Specification for Marble Dimension Stone |
+| ASTM C568 / C568M | Specification for Limestone Dimension Stone |
+| ASTM C615 / C615M | Specification for Granite Dimension Stone |
+| ASTM C616 / C616M | Specification for Quartz-Based (Sandstone) Dimension Stone |
+| ASTM C629 / C629M | Specification for Slate Dimension Stone |
+| ASTM C1526 | Specification for Serpentine Dimension Stone |
+| ASTM C1527 / C1527M | Specification for Travertine Dimension Stone |
+| ASTM C97 / C97M | Test Methods for Absorption and Bulk Specific Gravity of Dimension Stone |
+| ASTM C99 / C99M | Test Method for Modulus of Rupture of Dimension Stone |
+| ASTM C170 / C170M | Test Method for Compressive Strength of Dimension Stone |
+| ASTM C880 / C880M | Test Method for Flexural Strength of Dimension Stone |
+| ASTM C241 / C241M | Test Method for Abrasion Resistance of Stone Subjected to Foot Traffic |
+| ASTM C1353 / C1353M | Test Method for Abrasion Resistance of Dimension Stone Subjected to Foot Traffic Using a Rotary Platform Abraser |
+| ASTM C1028 | Test Method for Static Coefficient of Friction (superseded by ANSI A326.3 for slip resistance) |
+| ANSI A137.1 | Specifications for Ceramic Tile (referenced for tile-form stone dimensional and DCOF requirements) |
+| ANSI A108.01 / A108.02 | General Requirements and Materials, Environmental, and Workmanship for Installation of Tile |
+| ANSI A108.5 | Installation with Dry-Set or Latex-Portland Cement Mortar |
+| ANSI A108.6 | Installation with Chemical-Resistant, Water-Cleanable Tile-Setting and -Grouting Epoxy |
+| ANSI A108.13 | Installation of Load-Bearing, Bonded, Waterproof Membranes for Thin-Set Ceramic Tile and Dimension Stone |
+| ANSI A108.17 | Installation of Crack-Isolation Membranes for Thin-Set Ceramic Tile and Dimension Stone |
+| ANSI A118.1 | Dry-Set Portland Cement Mortar |
+| ANSI A118.3 | Chemical-Resistant, Water-Cleanable Tile-Setting and -Grouting Epoxy |
+| ANSI A118.4 | Modified Dry-Set Cement Mortar |
+| ANSI A118.5 | Chemical-Resistant Furan Mortars and Grouts |
+| ANSI A118.6 | Standard Cement Grouts |
+| ANSI A118.7 | High-Performance Cement Grouts |
+| ANSI A118.10 | Load-Bearing, Bonded, Waterproof Membranes for Thin-Set Installation |
+| ANSI A118.12 | Crack-Isolation Membranes for Thin-Set Installation |
+| ANSI A118.15 | Improved Modified Dry-Set Cement Mortar |
+| ANSI A326.3 | Test Method for Measuring Dynamic Coefficient of Friction of Hard-Surface Flooring Materials |
+| TCNA Handbook | TCNA Handbook for Ceramic, Glass, and Stone Tile Installation (method designations and movement-joint guideline EJ171) |
+| NSI Dimension Stone Design Manual | Natural Stone Institute Dimension Stone Design Manual |
+| IBC | International Building Code (current edition adopted by jurisdiction) |
+
+## All materials, testing, and installation shall comply with the latest edition adopted by the Authority Having Jurisdiction for each of the standards listed above.
+## Where the contract documents, a referenced standard, the TCNA Handbook method called out, the Natural Stone Institute Dimension Stone Design Manual, or the stone or setting-material manufacturer's or fabricator's written instructions impose a more stringent requirement than the minimum of any other standard, the more stringent requirement governs unless the Architect of Record directs otherwise in writing.
+## For natural stone the fabricator's and setting-material manufacturer's written instructions for the specific stone are not merely advisory, because a moisture-sensitive or friable stone has handling, setting, and sealing requirements the generic standards do not capture, and disregarding them voids the installation warranty. {note}
+## The ASTM dimension-stone material specifications (C503, C568, C615, C616, C629, C1526, C1527) are the foundation of this standard, each defining for its stone type the minimum physical properties — absorption per ASTM C97, density, compressive strength per ASTM C170, modulus of rupture per ASTM C99 and flexural strength per ASTM C880, and abrasion resistance per ASTM C1353 — that a sound, durable stone must meet. {note}
+## The TCNA Handbook supplies the tested installation methods by designation and the movement-joint guideline EJ171, the NSI Dimension Stone Design Manual is the recognized source for stone-specific selection and tolerance guidance, and where stone is supplied in tile form the dimensional and slip-resistance provisions of ANSI A137.1 and ANSI A326.3 also apply. {note}
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following for the Architect's review prior to procurement and installation:
+
+- Stone material certification reporting, for each stone, the commercial and geologic name, the quarry source, the governing ASTM specification, and the measured physical properties (absorption and density per ASTM C97, compressive strength per ASTM C170, flexural strength per ASTM C880 or modulus of rupture per ASTM C99, and abrasion resistance per ASTM C1353 for floor stone), demonstrating compliance with the governing specification
+- Product data for each setting material, membrane, grout, and accessory, identifying the governing ANSI specification and a written statement that the selected setting material, membrane, and grout are approved by their manufacturer for the specific stone and substrate and for the service condition, including an explicit statement of suitability for moisture-sensitive or translucent stone where such stone is specified
+- The TCNA Handbook method designation, or the NSI Dimension Stone Design Manual detail, proposed for each stone location, identifying the substrate, membrane, setting bed, and movement-joint treatment
+- Full-range samples and, for stone with significant directional vein or shade variation, full-size sample sets or a reviewed approved range establishing the acceptable extremes of color, vein, shade, and finish
+- Slip-resistance (DCOF) test data per ANSI A326.3 for each floor stone in its specified finish, identifying the use classification for which the value qualifies the stone
+- Shop drawings showing stone layout, setting-out and control lines, vein direction and match (book-match, slip-match, blend), the location of every movement and perimeter joint, edge and trim profiles, stair and threshold details, and slab jointing, coordinated with the [[drawing: finish plans, elevations, stone layout, and details]]
+- For slabs on or below grade and for moisture-sensitive stone, the substrate moisture test result and the basis for the membrane and setting-material selection
+- Sealer and impregnator product data with the stone manufacturer's or fabricator's confirmation of compatibility, and a statement of whether a pre-installation impregnating sealer is required
+
+```datasheet
+label: Action Submittals Required
+type: checkbox
+options:
+ - "Stone material certification — name, source, ASTM spec, and measured physical properties (C97, C170, C880/C99, C1353)"
+ - "Product data — setting materials, membranes, grout (ANSI designation + stone-specific compatibility statement)"
+ - "TCNA method / NSI detail per location"
+ - "Samples — full color/vein/shade range and approved range set"
+ - "DCOF slip-resistance data per ANSI A326.3 (floor stone, specified finish)"
+ - "Shop drawings — layout, vein match, movement joints, edge profiles, stair/threshold details"
+ - "Substrate moisture test result (slabs on/below grade and moisture-sensitive stone)"
+ - "Sealer/impregnator product data with compatibility confirmation"
+default: "Stone material certification — name, source, ASTM spec, and measured physical properties (C97, C170, C880/C99, C1353)"
+```
+
+### Installation shall not begin until the stone material certification, the setting-material compatibility statement, and, where applicable, the substrate moisture report have been submitted and reviewed.
+### The stone type and substrate condition together determine the setting material, the membrane, the sealing requirement, and the freeze-thaw suitability. {note}
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following closeout documentation:
+
+- Manufacturer warranty documentation for the stone, setting materials, and sealer, executed in the Owner's name where an owner-registered warranty is offered
+- Maintenance instructions describing permitted cleaning agents, the resealing interval and product, and prohibited cleaners (acidic cleaners on calcareous stone, abrasive pads on polished finishes) for each stone and finish
+- Attic-stock transmittal documenting the quantity, stone, finish, size, and block/lot of spare stone delivered to the Owner
+
+```datasheet
+label: Closeout Submittals Required
+type: checkbox
+options:
+ - "Manufacturer warranty documentation for stone, setting materials, and sealer (executed in Owner's name where offered)"
+ - "Maintenance instructions (permitted cleaning agents, resealing interval and product, prohibited cleaners)"
+ - "Attic-stock transmittal (quantity, stone, finish, size, block/lot of spare stone)"
+default: "Manufacturer warranty documentation for stone, setting materials, and sealer (executed in Owner's name where offered)"
+```
+
+# Quality Assurance {toc}
+
+## Installer Qualifications {toc}
+
+```datasheet
+label: Installer Qualification
+type: radio
+options:
+ - "Credentialed stone / large-format installer required (slabs, polished, moisture-sensitive, or any edge over 15 in)"
+ - "Experienced commercial natural-stone installer"
+ - "Experienced commercial tile installer (calibrated stone tile, interior dry only)"
+default: "Experienced commercial natural-stone installer"
+```
+
+### Stone shall be installed by an installer with documented experience in commercial natural-stone installations of the specific stone type, finish, and method required.
+### The Contractor should employ installers credentialed under a recognized industry program for stone and large-format work.
+### The Contractor shall not assign stone work — particularly moisture-sensitive, friable, polished, or large-slab stone — to labor experienced only in manufactured tile.
+### Stone work demands skills that ordinary tile work does not, including matching vein and shade across a wall, setting moisture-sensitive stone with epoxy, controlling lippage on large gauged slabs, dry-laying and blending from multiple crates, and finishing field-cut edges to match factory edges. {note}
+
+## Mock-Up {toc}
+
+```datasheet
+label: Mock-Up Required
+type: radio
+options:
+ - "Yes — representative area of each stone, including a movement joint, an edge/trim condition, and a wet-area or stair detail where applicable"
+ - "No"
+default: "Yes — representative area of each stone, including a movement joint, an edge/trim condition, and a wet-area or stair detail where applicable"
+```
+
+### Where a mock-up is required, the Contractor shall install a representative area of each stone type and finish at a location directed by the Architect, including at least one movement or perimeter joint, one edge or trim condition, one internal or external corner, one transition to an adjacent finish, and a stair, threshold, or wet-area detail where such conditions occur.
+### The mock-up shall remain available for comparison throughout the work.
+### For stone the mock-up establishes the accepted standard for the natural range of color, vein, and shade, the joint width and grout color, the lippage, the finish, and the sealer appearance, and because natural variation is intrinsic the approved range, not a single sample, defines acceptance. {note}
+
+## Lippage and Joint Acceptance {toc}
+
+```datasheet
+label: Maximum Allowable Lippage
+type: radio
+unit: in
+options:
+ - "1/32 in plus inherent warpage (joints under 1/4 in; gauged/calibrated stone)"
+ - "1/16 in plus inherent warpage (joints 1/4 in and wider)"
+ - "Per ANSI A108 / NSI for the joint width, stone, and finish"
+default: "Per ANSI A108 / NSI for the joint width, stone, and finish"
+```
+
+### Lippage — the difference in elevation between the edges of two adjacent units — shall not exceed the allowance of ANSI A108 and the NSI Dimension Stone Design Manual for the joint width, stone, and finish, plus any inherent warpage permitted for the stone.
+### The grout-joint width shall not be less than the minimum the stone's dimensional and thickness variation warrants.
+### Lippage is more conspicuous on stone than on tile because polished and honed stone reflects light across the joint and cleft and calibrated stone vary in thickness, and it becomes harder to control as unit size increases and joint width decreases, which is why large slabs demand a flatter substrate and a controlled minimum joint. {note}
+
+## Pre-Installation Conference {toc}
+
+### Before installation begins, the Contractor shall hold a pre-installation conference with the Architect, the stone fabricator, and the installer to review the stone type and its moisture sensitivity and friability, the substrate condition, flatness, and moisture, the TCNA method or NSI detail and the setting materials selected, the layout, vein-match, and blending plan, the movement-joint plan, the sealing requirement and sequence, and the environmental conditions in the space.
+### Most stone disputes trace to a property of the stone or a condition of the substrate that was known but not acted upon before setting, and the conference exists to surface and resolve those conditions before any stone is set. {note}
+
+# Environmental and Service Conditions {toc}
+
+## Service Environment Classification {toc}
+
+### The service environment determines the stone type and finish, the freeze-thaw suitability, the slip-resistance requirement, the membrane requirement, the setting and grouting materials, and the sealing regimen. {note}
+
+```datasheet
+label: Service Environment
+type: select
+drawing_ref: true
+options:
+ - "Interior dry — floors and walls not regularly wetted"
+ - "Interior wet — restrooms, showers, food service, fountains"
+ - "Interior heavy-duty — high-traffic lobbies, retail, transit floors"
+ - "Exterior, freeze-thaw exposed — protected exterior floors, walls, and paving"
+ - "Submerged / continuous-wet — pools, fountains, water features"
+default: "Interior dry — floors and walls not regularly wetted"
+```
+
+### The service environment shall be established for each stone location before materials are selected.
+### Calcareous stone in freeze-thaw exterior service shall be used only where the specific stone has demonstrated freeze-thaw durability.
+### The Contractor shall confirm the service classification for each location from the contract documents before selecting materials.
+### Interior dry applications tolerate the broadest range of stone and finishes, while interior wet applications require a waterproof assembly, slip-resistant floor stone, an appropriate setting material, and attention to efflorescence and staining in absorptive stone. {note}
+### Exterior and freeze-thaw applications require a dense, low-absorption stone because an absorptive stone — most limestone, most marble, many travertines and slates — will spall, delaminate, or deteriorate when absorbed water freezes, and submerged or continuous-wet service requires a non-staining low-absorption stone, an epoxy or non-efflorescing setting system, and engineering beyond this standard. {note}
+
+## Temperature During Installation and Cure {toc}
+
+```datasheet
+label: Minimum Ambient and Substrate Temperature During Installation and Cure
+type: range
+unit: °F
+options:
+ min: 50
+ max: 60
+ step: 5
+default: 50
+```
+
+### The installation area and the substrate shall be maintained at a minimum of 50 °F (10 °C) and a maximum of 100 °F (38 °C) during installation and for the cure period required by the setting and grouting materials, typically not less than 7 days for cementitious materials before exposure to water or traffic.
+### Cementitious mortars and grouts gain strength through hydration, which slows or stops below approximately 50 °F and which can flash-set or shrink-crack in excessive heat, epoxy materials have a still narrower temperature window, and stone set or grouted outside the window or trafficked before cure debonds or cracks at the bond line. {note}
+
+## Substrate Moisture {toc}
+
+```datasheet
+label: Substrate Moisture Management (slabs on/below grade)
+type: radio
+drawing_ref: true
+options:
+ - "Bonded waterproof membrane (ANSI A118.10) over slab — wet areas, moisture-sensitive or absorptive stone"
+ - "Vapor-managing / moisture-tolerant assembly with cementitious setting bed — durable non-sensitive stone only"
+ - "Standard thin-set over sound dry slab — interior dry, above-grade, durable stone only"
+default: "Bonded waterproof membrane (ANSI A118.10) over slab — wet areas, moisture-sensitive or absorptive stone"
+```
+
+### Where stone is installed over concrete slabs on or below grade, the substrate moisture condition shall be evaluated and a bonded waterproof or vapor-managing membrane provided where moisture would otherwise drive efflorescence, staining, debonding, or warping through the assembly.
+### Where the assembly includes moisture-sensitive stone or a moisture-sensitive membrane or adhesive, the substrate moisture shall be measured (the relative-humidity method of ASTM F2170 being the recognized measure) and the membrane and setting materials selected for the measured condition.
+### Natural stone is far more vulnerable to substrate moisture than manufactured tile, because residual slab moisture and alkalinity carry mineral salts that deposit as efflorescence on and within absorptive stone, stain light and translucent stone, and in moisture-sensitive stone supply the water that causes warping and bond loss. {note}
+
+## Lighting for Inspection {toc}
+
+### Permanent or equivalent temporary lighting shall be operating during installation and inspection so that lippage, shade and vein match, joint alignment, hollow-bonded areas, finish uniformity, and surface defects can be evaluated under realistic conditions.
+### The finished work shall be evaluated under the lighting in which it will be viewed in service, except that critical-light conditions called out in the contract documents shall be evaluated under raking light if specified.
+### Polished and honed stone is highly sensitive to raking light, which exaggerates lippage and finish variation. {note}
+
+# Stone Products {toc}
+
+## Stone Type and Governing Specification {toc}
+
+### The stone type and its governing ASTM specification determine the service environment, the freeze-thaw suitability, the strength, the absorption and staining behavior, the moisture sensitivity, the appropriate finishes, and the maintenance regimen. {note}
+
+```datasheet
+label: Stone Type
+type: select
+drawing_ref: true
+options:
+ - "Granite (ASTM C615) — dense igneous; floors, exterior, high-traffic, wet"
+ - "Marble (ASTM C503) — calcareous metamorphic; interior floors and walls"
+ - "Limestone (ASTM C568) — calcareous sedimentary; interior, protected exterior"
+ - "Travertine (ASTM C1527) — porous calcareous; interior floors and walls (filled/unfilled)"
+ - "Slate (ASTM C629) — fissile metamorphic; floors, treads, exterior paving"
+ - "Quartzite / quartz-based sandstone (ASTM C616) — siliceous; durable floors and exterior"
+ - "Serpentine 'green marble' (ASTM C1526) — moisture-sensitive; interior, epoxy-set"
+default: "Marble (ASTM C503) — calcareous metamorphic; interior floors and walls"
+```
+
+### The stone type shall be selected for the use, traffic, exposure, and maintenance expectations of each space, shall be identified by both commercial and geologic name and quarry source, and shall be indicated in the [[drawing: stone schedule]].
+### Each stone shall comply with its governing ASTM dimension-stone specification (C503, C568, C615, C616, C629, C1526, or C1527) and shall be certified by measured physical properties.
+### Stone used in exterior, freeze-thaw, or submerged service shall be a dense, low-absorption stone demonstrated to be durable in that service.
+### Calcareous stone shall not be used in freeze-thaw exterior service unless the specific stone is documented as freeze-thaw durable.
+### Granite (ASTM C615) is a dense igneous stone of very low absorption (typically not more than about 0.40 percent) and high strength, the most durable common stone and the default for high-traffic, wet, and exterior freeze-thaw floors, while marble (ASTM C503) is a calcareous metamorphic interior stone, soft and acid-sensitive, etched by acids and unsuitable in most cases for exterior freeze-thaw service. {note}
+### Limestone (ASTM C568) is a calcareous sedimentary stone classified by density into three types whose use is governed by the class, travertine (ASTM C1527) is a porous calcareous stone with natural voids that may be filled or unfilled, slate (ASTM C629) is a fissile cleft stone whose absorption and iron content require attention to staining, quartz-based sandstone and quartzite (ASTM C616) are durable siliceous stones, and serpentine "green marble" (ASTM C1526) is the archetypal moisture-sensitive stone. {note}
+
+## Limestone Density Classification {toc}
+
+```datasheet
+label: Limestone Density Class (ASTM C568)
+type: radio
+options:
+ - "Type I — low density (interior, light service)"
+ - "Type II — medium density (interior floors and walls, general)"
+ - "Type III — high density (high-traffic floors, protected exterior)"
+ - "Not applicable — stone is not limestone"
+default: "Type II — medium density (interior floors and walls, general)"
+```
+
+### Where limestone is specified, the density class of ASTM C568 shall be selected for the service.
+### Because absorption, density, compressive strength, and modulus of rupture all rise with the class, a low-density Type I limestone suited to a protected interior wall will absorb, stain, and wear unacceptably as a high-traffic floor where a high-density Type III is required, so selecting limestone without specifying the class invites the wrong stone. {note}
+
+## Physical Properties {toc}
+
+```datasheet
+label: Minimum Abrasion Hardness (Ha) for Floor Stone (ASTM C1353)
+type: select
+options:
+ - "Ha 10 — light residential / very light commercial"
+ - "Ha 12 — moderate commercial floor traffic"
+ - "Ha 15 — heavy commercial / institutional floor traffic"
+ - "Per governing ASTM specification for the stone"
+default: "Per governing ASTM specification for the stone"
+```
+
+### Each floor stone, and each stone in structural or exterior service, shall meet the minimum physical properties of its governing ASTM specification for absorption, density, compressive strength, flexural strength or modulus of rupture, and (for floors) abrasion resistance, verified by the test methods cited and reported in the stone certification.
+### Water absorption shall be determined per ASTM C97 and shall not exceed the maximum of the governing specification for the stone and class.
+### Low absorption shall be confirmed for any stone in wet or freeze-thaw service.
+### Compressive strength shall be determined per ASTM C170 and flexural strength per ASTM C880 (or modulus of rupture per ASTM C99), each meeting the minimum of the governing specification.
+### Abrasion resistance of floor stone shall be determined per ASTM C1353 and the abrasion hardness shall be appropriate to the traffic (light, moderate, or heavy commercial).
+### These properties are not interchangeable between stones nor assumable from the commercial name, because two stones sold as "marble" or "quartzite" can differ by an order of magnitude in absorption and strength, and only the measured values against the governing specification establish suitability. {note}
+
+## Stone Form and Thickness {toc}
+
+### The stone form and thickness determine the setting method, the substrate flatness requirement, the handling, and the joint and lippage control. {note}
+
+```datasheet
+label: Stone Form
+type: select
+drawing_ref: true
+options:
+ - "Gauged / calibrated stone tile — uniform thickness, thin-bed set"
+ - "Cleft-finish tile (slate, quartzite) — variable thickness"
+ - "Cut-to-size dimension stone — fabricator-cut to plan"
+ - "Thin slab — large-format gauged slab"
+ - "As scheduled"
+default: "Gauged / calibrated stone tile — uniform thickness, thin-bed set"
+```
+
+```datasheet
+label: Nominal Stone Thickness
+type: range
+unit: in
+drawing_ref: true
+options:
+ min: 0.375
+ max: 0.75
+ step: 0.125
+ setpoints: [0.375, 0.5, 0.625, 0.75]
+default: 0.375
+```
+
+### The stone thickness shall be coordinated with the stone strength, the span and support, and the anticipated load, and indicated in the [[drawing: stone schedule and details]].
+### Gauged calibrated stone tile of uniform thickness is set by the thin-bed method, cleft-finish stone such as slate varies in thickness and is set by a medium-bed or full mortar-bed method that accommodates the variation, and floor stone thinner than the stone's strength warrants will crack over any support gap. {note}
+
+## Surface Finish {toc}
+
+### The finish affects appearance, slip resistance, cleanability, maintenance, and durability. {note}
+
+```datasheet
+label: Surface Finish
+type: select
+drawing_ref: true
+options:
+ - "Polished — high gloss (interior walls, low-traffic floors, countertops)"
+ - "Honed — smooth matte (interior floors and walls, general)"
+ - "Flamed (thermal) — coarse slip-resistant (granite floors, exterior)"
+ - "Brushed / antiqued — textured low-sheen"
+ - "Sandblasted — uniform matte texture"
+ - "Cleft (natural split) — slate and quartzite"
+ - "Tumbled — softened edges and surface"
+default: "Honed — smooth matte (interior floors and walls, general)"
+```
+
+### The finish shall be selected for the stone, the service, and the slip-resistance requirement, and shall be consistent with the approved mock-up.
+### Polished finishes shall not be used on wet floors or sloped surfaces where the slip-resistance requirement cannot be met.
+### A polished finish maximizes color and reflectivity but minimizes slip resistance and is best reserved for walls, countertops, and low-traffic feature floors, a honed finish is the general-purpose floor and wall finish, flamed and brushed finishes are the standard for granite floors and exterior paving, and cleft finishes occur naturally on slate and some quartzite. {note}
+
+## Slip Resistance {toc}
+
+```datasheet
+label: Dynamic Coefficient of Friction (ANSI A326.3)
+type: range
+unit: DCOF
+options:
+ min: 0.42
+ max: 0.60
+ step: 0.01
+ setpoints: [0.42, 0.50, 0.60]
+default: 0.42
+```
+
+### The dynamic coefficient of friction of floor stone in its specified finish shall be measured per ANSI A326.3 and shall meet the minimum for the applicable use classification.
+### Ramps, shower floors, pool decks, entries subject to tracked-in water, and stair treads require classification-specific values and a textured finish and shall not be defaulted to the level-interior-wet minimum.
+### A minimum DCOF of 0.42 applies to a level interior floor walked upon when wet while wetter and sloped classifications require higher values, the result is meaningful only for the classification under which it was reported, and because slip resistance is a property of the finished surface as installed and maintained the value alone does not predict whether a slip will occur but provides a comparative basis for selecting a finish. {note}
+
+# Setting Materials {toc}
+
+## Setting Method {toc}
+
+```datasheet
+label: Setting Method
+type: select
+drawing_ref: true
+options:
+ - "Thin-bed (thin-set) — gauged stone over a flat, sound substrate"
+ - "Medium-bed mortar — large units and slightly variable thickness, sloped floors"
+ - "Thick-bed (full mortar bed) — variable-thickness cleft stone, leveling required, exterior"
+default: "Thin-bed (thin-set) — gauged stone over a flat, sound substrate"
+```
+
+### The setting method shall match the stone form, the substrate flatness, and the service.
+### The method shall be drawn from the TCNA Handbook or NSI Dimension Stone Design Manual and shown on the [[drawing: details]].
+### The thin-bed method bonds gauged stone to a flat substrate and is the standard for calibrated stone tile, the medium-bed method uses a mortar applied in a thicker bed for large units and modest thickness variation, and the thick-bed full mortar-bed method accommodates variable-thickness cleft stone, establishes slope to drains, and remains the most robust method for cleft slate, sloped wet-area floors, and demanding exterior work. {note}
+
+## Bonding Mortar Type {toc}
+
+```datasheet
+label: Bonding Mortar Type
+type: select
+drawing_ref: true
+options:
+ - "Modified dry-set cement mortar (ANSI A118.4) — general durable stone, floors and walls"
+ - "Improved modified dry-set cement mortar (ANSI A118.15) — large units, slabs, demanding bond"
+ - "Epoxy mortar (ANSI A118.3) — moisture-sensitive stone, chemical exposure, maximum bond"
+ - "Dry-set cement mortar (ANSI A118.1) — absorptive stone over a cured mortar bed"
+default: "Modified dry-set cement mortar (ANSI A118.4) — general durable stone, floors and walls"
+```
+
+### The bonding mortar shall be selected for the stone type, the substrate, and the service, shall comply with the governing ANSI A118 specification, and shall be approved by its manufacturer for the specific stone.
+### Where a fast-setting or rapid-cure mortar is needed, it shall be a product the stone manufacturer approves for the stone, because some rapid-set mortars develop heat or alkalinity that stains sensitive stone.
+### Mortar selection for stone is not interchangeable with tile practice, because the stone's moisture sensitivity, translucency, and the staining risk from the mortar itself all govern the choice, and the wrong mortar produces warping, picture-framing, or staining that no later remedy can fully correct. {note}
+### Modified dry-set cement mortar (ANSI A118.4) is the default for durable non-sensitive stone, improved modified mortar (ANSI A118.15) provides higher bond and coverage for large units and slabs, epoxy mortar (ANSI A118.3) is required for moisture-sensitive stone and chemical exposure, and unmodified dry-set mortar (ANSI A118.1) suits absorptive stone over a cured Portland-cement mortar bed. {note}
+
+## Moisture-Sensitive Stone {toc}
+
+```datasheet
+label: Moisture-Sensitive Stone Setting Requirement
+type: radio
+options:
+ - "Epoxy mortar (ANSI A118.3) with 100% coverage — required for serpentine 'green marble' and other moisture-sensitive stone"
+ - "Manufacturer-approved non-water setting system for the specific sensitive stone"
+ - "Not applicable — stone is not moisture-sensitive"
+default: "Not applicable — stone is not moisture-sensitive"
+```
+
+### Moisture-sensitive stone — chiefly serpentine "green marble," and certain marbles, slates, and resin-backed stones identified by the fabricator — shall be set only with an epoxy mortar conforming to ANSI A118.3, or another non-water-bearing system the stone manufacturer approves, applied to achieve full (100 percent) coverage.
+### The Contractor shall confirm with the fabricator whether each stone is moisture-sensitive before selecting a mortar.
+### The Contractor shall not set a moisture-sensitive stone with any water-bearing cement or latex mortar under any circumstances.
+### Moisture-sensitive stone absorbs water from a water-based cement or latex mortar and warps, curling its edges away from the substrate and destroying the bond, whereas epoxy mortar contains no water and sets these stones without driving the warping, and full coverage prevents any joint or edge from absorbing water or being left unsupported. {note}
+
+## White Mortar for Translucent and Light Stone {toc}
+
+```datasheet
+label: Mortar Color for Translucent / Light Stone
+type: radio
+options:
+ - "White-pigmented setting mortar required — translucent, white, and light-colored stone"
+ - "Standard (gray) mortar acceptable — opaque, dark, or dense stone"
+default: "White-pigmented setting mortar required — translucent, white, and light-colored stone"
+```
+
+### White marble, onyx, light limestone, and other translucent or light-colored stone shall be set with a white-pigmented setting mortar to prevent shadowing of the stone color.
+### The Contractor shall verify the stone's translucency on the mock-up and select the mortar color accordingly.
+### A gray cement mortar shows through a translucent or thin light stone and shadows or darkens its appearance unevenly, a defect known as telegraphing that cannot be corrected after setting, and only a white mortar preserves the true color of the stone. {note}
+
+## Crack-Isolation Membrane {toc}
+
+```datasheet
+label: Crack-Isolation Membrane (ANSI A118.12)
+type: radio
+drawing_ref: true
+options:
+ - "Required over the full floor — concrete subject to shrinkage cracking or minor in-plane movement"
+ - "Required at existing cracks and joints only (spot membrane)"
+ - "Not required — substrate sound and not subject to in-plane cracking"
+default: "Required at existing cracks and joints only (spot membrane)"
+```
+
+### A crack-isolation membrane conforming to ANSI A118.12 and installed per ANSI A108.17 shall be provided where the substrate is subject to minor in-plane movement or shrinkage cracking that would otherwise telegraph through and crack the stone.
+### Structural and moving joints shall be carried through the stone as movement joints regardless of any membrane, because a crack-isolation membrane addresses minor in-plane movement only and does not substitute for the movement joints required by EJ171.
+
+## Waterproof Membrane {toc}
+
+```datasheet
+label: Waterproof Membrane (ANSI A118.10)
+type: radio
+drawing_ref: true
+options:
+ - "Required — showers, wet areas, exterior, and over occupied space"
+ - "Required at shower receptors and pans only"
+ - "Not required — interior dry application"
+default: "Required — showers, wet areas, exterior, and over occupied space"
+```
+
+### A load-bearing bonded waterproof membrane conforming to ANSI A118.10 and installed per ANSI A108.13 shall be provided in showers, steam rooms, wet areas, exterior installations, and any stone assembly over occupied or moisture-sensitive space.
+### Where a single membrane is selected for both the waterproofing and crack-isolation functions, the Contractor shall verify it is certified to both standards.
+### Stone and cementitious joints are not waterproof, since water passes through joints and through absorptive stone over time, and a continuous bonded waterproof membrane keeps water out of the structure and limits the moisture that drives efflorescence and staining, while many ANSI A118.10 membranes also satisfy the crack-isolation requirements of A118.12. {note}
+
+# Joint Materials {toc}
+
+## Grout and Pointing {toc}
+
+```datasheet
+label: Joint Filler
+type: select
+drawing_ref: true
+options:
+ - "High-performance cement grout (ANSI A118.7) — general stone floors and walls"
+ - "Standard cement grout (ANSI A118.6) — interior light-duty"
+ - "Epoxy grout (ANSI A118.3) — chemical exposure, food service, maximum stain resistance"
+ - "Unsanded cement grout — narrow joints in polished stone (prevents scratching)"
+default: "High-performance cement grout (ANSI A118.7) — general stone floors and walls"
+```
+
+### The joint filler shall be selected for the joint width, the stone finish, the service, and the stain- and chemical-resistance requirement, and shall comply with the governing ANSI specification.
+### For narrow joints in polished stone, an unsanded grout shall be used because the sand in a sanded grout scratches a polished surface during tooling and cleaning.
+### Grout containing pigments or aggressive constituents that could stain a sensitive or absorptive stone shall not be used without the stone manufacturer's confirmation.
+### Absorptive and sensitive stone shall be pre-sealed before grouting where the grout would otherwise stain the stone.
+### High-performance cement grout (ANSI A118.7) is the general default for stone floors and walls, and epoxy grout (ANSI A118.3) is used where chemical resistance, maximum stain resistance, or a non-absorptive joint is required. {note}
+
+## Grout Joint Width {toc}
+
+```datasheet
+label: Grout Joint Width
+type: range
+unit: in
+drawing_ref: true
+options:
+ min: 0.0625
+ max: 0.375
+ setpoints: [0.0625, 0.125, 0.1875, 0.25, 0.375]
+default: 0.125
+```
+
+### The joint width shall be selected for the stone size, edge type, and thickness variation, and shall not be less than the minimum the stone's dimensional variation warrants.
+### The joint width shall be shown in the [[drawing: stone schedule and details]].
+### Gauged stone with a precise edge can take a narrow joint while cleft and tumbled stone with irregular edges requires a wider joint, because running a joint narrower than the stone's dimensional and thickness variation produces visible lippage and uneven joints. {note}
+
+# Movement Joints {toc}
+
+## Movement Joint Design {toc}
+
+```datasheet
+label: Field Movement Joint Spacing — Interior
+type: range
+unit: ft
+drawing_ref: true
+options:
+ min: 20
+ max: 25
+ step: 1
+ setpoints: [20, 25]
+default: 25
+```
+
+```datasheet
+label: Field Movement Joint Spacing — Exterior or Sunlight/Moisture Exposed
+type: range
+unit: ft
+drawing_ref: true
+options:
+ min: 8
+ max: 12
+ step: 1
+ setpoints: [8, 12]
+default: 12
+```
+
+### Movement joints shall be provided throughout stone work in accordance with the TCNA movement-joint guideline EJ171, and their locations shall be shown on the [[drawing: stone shop drawings and details]] before any stone is set.
+### Interior field movement joints shall be provided at the spacing EJ171 establishes for interior conditions, commonly on the order of 20 to 25 feet in each direction.
+### Exterior installations, and interior installations exposed to direct sunlight or to moisture and wide temperature swings, shall have field movement joints at substantially closer spacing, commonly on the order of 8 to 12 feet in each direction, because the larger thermal and moisture movement of an exposed assembly builds destructive stress over a shorter run.
+### The closer of the EJ171 requirement and any project-specific requirement governs.
+### Perimeter movement joints shall be provided where stone abuts restraining surfaces, walls, columns, curbs, and dissimilar floors.
+### Movement joints shall be carried through over every structural, cold, and control joint in the substrate and at every change in substrate plane or material.
+### Movement joints shall be left open of grout and filled with the specified sealant or fitted with a preformed movement-joint profile.
+### Movement joints allow the assembly to expand and contract without building the compressive stress that causes stone to tent, debond, and crack, and omitting field movement joints in a large floor is a leading cause of catastrophic failure because thermal and moisture expansion with no place to go lifts the stone off the floor in a ridge. {note}
+
+## Movement Joint Filler {toc}
+
+```datasheet
+label: Movement Joint Filler
+type: radio
+drawing_ref: true
+options:
+ - "Field-applied elastomeric sealant over backer rod / bond breaker"
+ - "Preformed metal or rigid movement-joint profile"
+ - "Preformed flexible movement-joint profile"
+default: "Field-applied elastomeric sealant over backer rod / bond breaker"
+```
+
+### Movement joints shall be filled with an elastomeric sealant of the type and color specified, installed over a backer rod or bond breaker so the sealant adheres only to the two joint faces and can stretch and compress, or shall be fitted with a preformed movement-joint profile suited to the traffic and exposure.
+### The sealant shall be a non-staining sealant compatible with the stone, verified non-staining on the specific stone where the joint is in contact with absorptive stone.
+### The sealant or profile shall be capable of the movement the joint will see.
+### A movement-joint sealant must adhere only to the two joint faces so it can stretch and compress freely, because bonding to the joint bottom restrains and tears it, and many common sealants bleed plasticizers that stain absorptive stone, so a sealant tested non-staining on the specific stone is required. {note}
+
+# Substrate Preparation {toc}
+
+## General Substrate Requirements {toc}
+
+### The substrate shall be structurally sound, clean, dimensionally stable, and free of dust, paint, oil, grease, curing and sealing compounds, sealers, laitance, efflorescence, and any other bond-inhibiting substance.
+### Concrete substrates shall be fully cured and shall present an open, absorptive surface; troweled-smooth, sealed, or curing-compound-treated concrete shall be mechanically abraded or shot-blasted to an open profile before stone is set, because the setting mortar bonds mechanically and cannot grip a sealed or contaminated surface.
+### The Contractor shall verify the condition of the substrate before installation and shall not set stone over a noncompliant substrate.
+### Setting stone over a noncompliant substrate transfers a known defect into the finished work, which is why the condition of the substrate is the Contractor's responsibility to verify before installation. {note}
+
+## Flatness Tolerance {toc}
+
+```datasheet
+label: Substrate Flatness Tolerance
+type: radio
+unit: in
+options:
+ - "1/4 in in 10 ft and 1/16 in in 1 ft (gauged stone with all edges under 15 in)"
+ - "1/8 in in 10 ft and 1/16 in in 2 ft (large units and slabs, any edge 15 in and over)"
+ - "Per the requirement for the stone size, form, and method"
+default: "Per the requirement for the stone size, form, and method"
+```
+
+### The substrate shall meet the flatness tolerance required for the stone size, form, and method.
+### High spots shall be ground down and low spots filled with a cementitious patching or self-leveling underlayment compatible with the setting system.
+### Where cleft variable-thickness stone is set by the thick-bed method, the mortar bed accommodates substrate variation, but the finished stone surface shall still meet the flatness and lippage tolerances of this standard.
+### For gauged stone with all edges under 15 inches the recognized tolerance is 1/4 inch in 10 feet and 1/16 inch in 1 foot, while for large units and slabs with any edge 15 inches and over it tightens to 1/8 inch in 10 feet and 1/16 inch in 2 feet, because a large rigid unit will rock on an undulation a small unit would tolerate. {note}
+
+## Substrate Type Verification {toc}
+
+```datasheet
+label: Substrate Type
+type: select
+drawing_ref: true
+options:
+ - "Concrete slab — cured, sound, profiled"
+ - "Cementitious backer unit over framing — walls and floors"
+ - "Cured Portland cement mortar bed (thick-bed)"
+ - "Existing sound tile / terrazzo (bond-coat or membrane over)"
+default: "Concrete slab — cured, sound, profiled"
+```
+
+### The setting system and method shall match the substrate type.
+### Stone over wood-framed floors shall be set over an appropriate backer board or uncoupling/crack-isolation membrane rated for the stone, and the floor deflection shall be verified within the limit the stone tolerates.
+### Stone shall not be set over a deflecting floor regardless of the mortar.
+### Stone over wood-framed floors requires a stiff floor and an appropriate backer board or membrane because wood expands, contracts, and deflects with moisture and load and will crack stone bonded directly to it, and heavy or large stone over wood framing requires verifying the floor deflection is within the limit the stone tolerates. {note}
+
+# Installation {toc}
+
+## Layout and Blending {toc}
+
+```datasheet
+label: Vein / Pattern Match
+type: select
+drawing_ref: true
+options:
+ - "Blend / random — distribute natural variation evenly"
+ - "Book-match — mirror-matched adjacent slabs"
+ - "Slip-match (side-slide) — repeating vein run"
+ - "Vein-directional — consistent vein direction"
+ - "As detailed on drawings"
+default: "Blend / random — distribute natural variation evenly"
+```
+
+### The Contractor shall establish the layout from the control lines and setting-out points shown on the [[drawing: finish plan and stone layout]] so that border and cut units are balanced and of adequate width, full units fall at the most prominent locations, vein and pattern align and match as the design requires, and movement joints fall where the design and EJ171 require.
+### Because natural stone varies, the Contractor shall dry-lay and blend the stone from several crates at once, distributing the natural range of color, vein, and shade across the work so that no concentration of dark, light, or heavily veined pieces forms a blotch, and shall obtain the Architect's approval of the dry-laid blend and vein match before setting.
+### Layout and blending shall be completed and approved before any mortar is spread.
+### Where book-match, slip-match, or directional veining is specified, the stone shall be sequenced and oriented to achieve the match shown on the shop drawings, and the fabricator's numbered layout shall be followed.
+### Book-matched and directional work is unforgiving, since a single piece set out of sequence or rotated breaks the pattern, which is the reason approved numbered shop drawings and crate sequencing are required. {note}
+
+## Mortar Application and Coverage {toc}
+
+```datasheet
+label: Minimum Mortar Coverage Beneath Stone
+type: radio
+unit: %
+options:
+ - "80% — interior dry floors and walls (durable stone)"
+ - "95% — exterior, wet areas, and heavy/rolling-load floors"
+ - "100% — moisture-sensitive stone (epoxy-set)"
+default: "95% — exterior, wet areas, and heavy/rolling-load floors"
+```
+
+### Bonding mortar shall be applied with the trowel notch, technique, and open time the mortar and stone require, combed in one direction with directional troweling, and the stone set with a slight perpendicular movement to collapse the ridges and eliminate voids.
+### The mortar coverage achieved beneath the stone shall be not less than 80 percent for interior dry applications and not less than 95 percent for exterior, wet, and heavy-load applications, with full coverage at edges and corners and no voids beneath.
+### Moisture-sensitive stone shall achieve full (100 percent) coverage.
+### Large units, slabs, and all floor stone shall be back-buttered in addition to combing the substrate to achieve the required coverage.
+### Stone shall be set with full mortar coverage at all edges and corners and with no voids beneath, verified by periodic removal and inspection of set stone.
+### Inadequate coverage is a leading cause of stone cracking, debonding, and hollow floors, because a stone bridging a void fractures under load and an edge void admits water, and the required coverage cannot reliably be achieved on a large or floor unit by combing the substrate alone, which is why such units are back-buttered. {note}
+
+## Beating-In and Lippage Control {toc}
+
+### Floor stone shall be beaten in or rolled with a beating block or the manufacturer's tool, and large units and slabs shall be set with a mechanical lippage-control (leveling) system where required, to seat the stone fully into the mortar, collapse the ridges, and bring adjacent edges into plane within the lippage allowance.
+### Polished and honed stone makes lippage conspicuous under reflected light, so the lippage tolerance is tighter and the leveling discipline more important than for textured tile. {note}
+
+## Grouting and Pointing {toc}
+
+### Grouting shall not begin until the bonding mortar has cured for the period the mortar manufacturer requires, typically not less than 24 to 72 hours.
+### Absorptive and sensitive stone shall be sealed with an impregnating sealer before grouting where the grout would otherwise stain the stone face.
+### Joints shall be cleaned of mortar and debris to a uniform depth, the grout worked fully into the joints to fill them solid, the excess struck off, and the surface cleaned promptly to remove grout residue before it cures onto the stone.
+### For polished stone, an unsanded grout shall be used and the cleaning performed before any abrasive residue can scratch the finish.
+### Joints intended to function as movement joints shall be left open of grout and shall not be filled with grout under any circumstances.
+### Grouting before the bonding mortar has cured disturbs the bond, and grouting absorptive or sensitive stone without first sealing it lets grout pigment stain the stone face permanently. {note}
+
+## Curing and Protection {toc}
+
+### The completed stone shall be protected from traffic and from other trades during the cure period and shall not be exposed to water, washing, or traffic until the setting and grouting materials have cured for the period they require, typically not less than 7 days for cementitious materials.
+### Floors shall be protected with a breathable covering that does not trap moisture against the stone, does not transfer color or adhesive, and does not stain the stone.
+### Protective coverings and tapes in contact with stone shall be verified non-staining for the specific stone.
+### Heavy construction traffic, rolling loads, and point loads shall be kept off the floor until cure is complete.
+### Many common protective films and tapes stain absorptive and polished stone, so only products verified non-staining on the specific stone may be placed in contact with it. {note}
+
+# Field Testing and Inspection {toc}
+
+## Bond and Installation Inspection {toc}
+
+```datasheet
+label: Post-Installation Inspection Required
+type: radio
+options:
+ - "Yes — full-area sounding and visual inspection under permanent lighting"
+ - "No"
+default: "Yes — full-area sounding and visual inspection under permanent lighting"
+```
+
+### After installation and cure, the stone shall be inspected for full bond, with no hollow-sounding (unbonded) units, no lippage exceeding the allowance, no cracked, chipped, or warped units, uniform joints fully packed and free of voids, correct vein match and shade blend, the specified finish uniform and free of scratches and grout residue, and movement joints correctly formed and left open of grout, under the permanent or equivalent lighting.
+### Stone shall be sounded — tapped to detect the hollow ring of an unbonded unit — across the floor, and hollow or unbonded units shall be removed and reset.
+### The Contractor shall confirm by periodic removal of set stone that the required mortar coverage was achieved across the work.
+### Sounding the stone to detect the hollow ring of an unbonded unit, and periodic removal of set stone, are the means by which bond and the achieved mortar coverage are confirmed after cure. {note}
+
+## Stone Property Verification {toc}
+
+### Stone is a natural material whose properties vary across a quarry; verification testing of the actual supplied lot guards against substitution of a weaker or more absorptive stone than was certified. {note}
+
+```datasheet
+label: Independent Stone Property Verification
+type: radio
+options:
+ - "Required — test supplied lot against governing ASTM specification"
+ - "Not required — manufacturer certification accepted"
+default: "Not required — manufacturer certification accepted"
+```
+
+### Where required by the contract documents or where the stone source is unverified, samples of the supplied stone shall be tested by an independent laboratory for the physical properties of the governing ASTM specification (absorption per ASTM C97, compressive strength per ASTM C170, flexural strength per ASTM C880 or modulus of rupture per ASTM C99, and abrasion per ASTM C1353 for floor stone) to confirm that the delivered stone meets the certified values.
+
+# Cleaning, Sealing, and Protection {toc}
+
+## Cleaning {toc}
+
+### After cure, the stone shall be cleaned of grout residue, construction soil, and marks using only cleaners the stone manufacturer permits for the specific stone and finish.
+### Acidic cleaners shall not be used on calcareous stone (marble, limestone, travertine, serpentine) because acids etch and dissolve the surface, dulling polish and pitting the stone.
+### Abrasive pads and powders shall not be used on polished finishes because they scratch the surface.
+### The permitted cleaners and the prohibited cleaners for each stone shall be recorded in the maintenance instructions.
+### Acids etch and dissolve calcareous stone and abrasive pads and powders scratch polished finishes, and because the permitted and prohibited cleaners differ by stone and finish they must be recorded so the Owner does not damage the stone in service. {note}
+
+## Sealing {toc}
+
+```datasheet
+label: Sealer / Impregnator
+type: select
+options:
+ - "Penetrating impregnating sealer — absorptive interior stone (marble, limestone, travertine, slate)"
+ - "Penetrating sealer rated for wet / exterior service"
+ - "Pre-grout impregnating sealer plus final sealer — stain-prone absorptive stone"
+ - "No sealer — dense low-absorption stone (most granite, dense quartzite) where not required"
+default: "Penetrating impregnating sealer — absorptive interior stone (marble, limestone, travertine, slate)"
+```
+
+### Absorptive stone shall be sealed with a penetrating impregnating sealer compatible with the stone and finish, applied after the stone and grout have cured for the period the products require, to reduce absorption, staining, and etching susceptibility.
+### The sealer shall be a penetrating impregnating type compatible with the stone and finish; film-forming sealers shall be used only where the manufacturer recommends them for the specific stone.
+### The sealer, the resealing interval, and the application method shall be documented in the maintenance instructions.
+### A penetrating impregnating sealer is preferred over a film-forming sealer for floors because a topical film wears unevenly, can reduce slip resistance, and traps moisture, stain-prone absorptive stone may require a pre-grout sealer in addition to the final sealer, and dense low-absorption stone that does not benefit from sealing need not be sealed. {note}
+
+# Delivery, Storage, and Handling {toc}
+
+## Stone, setting materials, grout, membranes, sealers, and accessories shall be delivered in the manufacturer's original packaging with labels and crate markings intact, identifying stone, finish, size, and block/lot.
+## Stone shall be stored indoors where practicable, protected from weather, freezing, staining, and breakage, and kept off the ground on non-staining dunnage.
+## Cardboard, wood, and adhesives that stain absorptive stone when wet shall be kept from contact with the stone faces.
+## Cementitious setting materials and grout shall be stored dry and off the floor, and material that has hardened or exceeded its shelf life shall be discarded.
+## Epoxy and polymer components shall be stored within their storage-temperature window and discarded when their limited shelf life is exceeded.
+## Slabs shall be transported, stored, and handled in A-frames and moved with the clamps and frames the fabricator requires, because an unsupported slab cracks under its own weight.
+## All stone for a continuous area should be from the same block or lot wherever possible, because color, vein, and shade vary between blocks and a block change within a single visual field is apparent.
+## An unsupported slab cracks under its own weight, cardboard, wood, and adhesives that contact stone faces when wet stain absorptive stone, and color, vein, and shade vary between blocks, so material handling and lot control protect both the integrity and the appearance of the stone. {note}
+
+# Warranty {toc}
+
+```datasheet
+label: Stone and Setting-Material Manufacturer Warranty Period
+type: select
+unit: years
+options:
+ - "1 year (materials)"
+ - "As offered by the manufacturer for the products specified"
+default: "As offered by the manufacturer for the products specified"
+```
+
+```datasheet
+label: Installation Workmanship Warranty Period
+type: select
+options:
+ - "1 year from substantial completion"
+ - "2 years from substantial completion"
+default: "1 year from substantial completion"
+```
+
+## The stone supplier and setting-material manufacturers shall warrant their products against manufacturing and material defects for the period offered, and where a setting-material manufacturer offers an owner-registered system warranty covering the membrane, mortar, and grout as an installed system, that warranty should be obtained and executed in the Owner's name.
+## The Contractor shall warrant the installation — including substrate preparation, membrane and mortar selection and application, mortar coverage, vein match and shade blend, lippage and joint quality, grouting, movement-joint formation, and sealing — against defective workmanship for the project warranty period.
+## Manufacturer system warranties are typically void unless the complete tested system was installed per the manufacturer's instructions and the cited TCNA method or NSI detail, including the epoxy and white-mortar requirements for moisture-sensitive and translucent stone, and the installation record is part of the warranty basis. {note}
+## Failures arising from substrate movement where required movement joints were omitted, from warping of moisture-sensitive stone set with a water-bearing mortar, from water intrusion where a required waterproof membrane was omitted, from cleaning or sealing contrary to the manufacturer's instructions, or from loads exceeding the rated service are excluded from both warranties, and variation in color, vein, and shade within the approved range is an inherent characteristic of natural stone and not a defect. {note}
+
+# Spare and Extra Materials {toc}
+
+```datasheet
+label: Attic Stock Quantity
+type: range
+unit: % of installed area
+options:
+ min: 2
+ max: 5
+ step: 1
+default: 3
+```
+
+## The Contractor shall deliver to the Owner spare stone of each type, finish, and size installed, in the percentage of installed area stated, in full crates labeled with the stone, finish, size, and block/lot.
+## Spare stone shall be stored by the Owner in a dry, protected location on non-staining dunnage.
+## Attic stock from the same block or lot is especially important for natural stone because later-quarried replacement stone will differ in color, vein, and shade and cannot be matched, and the spare material allows the Owner to repair damage with stone that matches the original installation. {note}