1 Scope
NOTE This standard governs the materials and installation of ceramic tile — including glazed and unglazed ceramic, porcelain, quarry, glazed wall, and mosaic tile, and gauged porcelain tile panels and slabs — applied by the thin-bed (thin-set) method to floors, walls, wainscots, wet-area surrounds, and countertops in commercial and institutional construction. (1.1)
1.2Tile is specified across nearly every building type because it is durable, impervious or near-impervious when porcelain, cleanable, dimensionally stable, fire-resistant, and available in an enormous range of sizes, finishes, and visuals; it is the default finish for restrooms, kitchens, food-service areas, locker rooms, healthcare wet areas, building lobbies, and any space that must be repeatedly washed or that is routinely exposed to water.
NOTE The durability of the finished tile assembly, however, is governed far more by the substrate, the setting bed, the membrane, and the movement-joint design than by the tile itself: the overwhelming majority of tile failures in the field — debonding, cracking, lippage, grout failure, and efflorescence — originate in substrate movement, inadequate mortar coverage, omitted movement joints, or moisture that was never accounted for, not in a defect of the tile. (1.3)
NOTE A tile installation is a layered system consisting of the structural substrate, any cleavage membrane or backer board, the crack-isolation or waterproof membrane where required, the bonding mortar, the tile, the grout, and the movement and perimeter joints. (1.4)
1.5Each layer must be selected to be compatible with the layers above and below it and with the service condition, and the assembly as a whole must be selected from a recognized installation method that has been tested as a system.
NOTE Coordination of the substrate establishes conditions that are fixed long before tile work begins. (1.6)
1.7The concrete substrate, its surface finish, its curing, and the location of structural joints are coordinated with Cast In Place Concrete, because every structural and cold joint in the substrate and every change in substrate plane or material must be carried through the tile as a movement joint. NOTE Waterproofing of the building envelope is coordinated with
Below Grade Waterproofing where tile is applied over a waterproofed assembly.
(1.8) NOTE Transitions to adjacent finishes are coordinated with
Resilient Flooring and
Terrazzo so that thresholds, transition profiles, and finish-floor elevations reconcile, and tile applied over framed wall assemblies is coordinated with
Gypsum Board Assemblies so that the correct backer board — not standard gypsum board — is provided in wet areas.
(1.9) 1.10The Contractor shall treat the installation as a coordinated system.
1.11The Contractor shall select a method from the TCNA Handbook for Ceramic, Glass, and Stone Tile Installation appropriate to the substrate and service.
1.12The Contractor shall verify that the tile, mortar, membrane, and grout are mutually compatible and rated for the measured substrate condition.
1.13The Contractor shall not begin setting tile until the substrate has passed the flatness, soundness, and (where applicable) moisture acceptance criteria of this standard.
2 Referenced Standards
| Standard |
Title |
| ANSI A137.1 |
American National Standard Specifications for Ceramic Tile |
| ANSI A137.3 |
American National Standard Specifications for Gauged Porcelain Tiles and Gauged Porcelain Tile Panels/Slabs |
| ANSI A108.1A |
Installation of Ceramic Tile in the Wet-Set Method, with Portland Cement Mortar |
| ANSI A108.1B |
Installation of Ceramic Tile on a Cured Portland Cement Mortar Setting Bed with Dry-Set or Latex-Portland Cement Mortar |
| ANSI A108.4 |
Installation of Ceramic Tile with Organic Adhesives or Water Cleanable Tile-Setting Epoxy Adhesive |
| ANSI A108.5 |
Installation of Ceramic Tile with Dry-Set Portland Cement Mortar or Latex-Portland Cement Mortar |
| ANSI A108.6 |
Installation of Ceramic Tile with Chemical-Resistant, Water Cleanable Tile-Setting and -Grouting Epoxy |
| ANSI A108.10 |
Installation of Grout in Tilework |
| ANSI A108.12 |
Installation of Ceramic Tile with EGP (Exterior Glue Plywood) Latex-Portland Cement Mortar |
| 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 A108.19 |
Interior Installation of Gauged Porcelain Tiles and Gauged Porcelain Tile Panels/Slabs by the Thin-Bed Method |
| ANSI A118.1 |
Dry-Set Portland Cement Mortar |
| ANSI A118.3 |
Chemical-Resistant, Water Cleanable Tile-Setting and -Grouting Epoxy and Water Cleanable Tile-Setting Epoxy Adhesive |
| ANSI A118.4 |
Modified Dry-Set Cement Mortar |
| ANSI A118.6 |
Standard Cement Grouts |
| ANSI A118.7 |
High-Performance Cement Grouts |
| ANSI A118.10 |
Load Bearing, Bonded, Waterproof Membranes for Thin-Set Ceramic Tile and Dimension Stone Installation |
| ANSI A118.11 |
EGP (Exterior Glue Plywood) Latex-Portland Cement Mortar |
| ANSI A118.12 |
Crack Isolation Membranes for Thin-Set Ceramic Tile and Dimension Stone Installation |
| ANSI A118.15 |
Improved Modified Dry-Set Cement Mortar |
| ANSI A136.1 |
Organic Adhesives for Installation of Ceramic Tile |
| ANSI A326.3 |
Test Method for Measuring Dynamic Coefficient of Friction of Hard Surface Flooring Materials |
| ASTM C373 |
Test Methods for Determination of Water Absorption of Fired Ceramic Tile (Classification Basis) |
| ASTM C627 |
Test Method for Evaluating Ceramic Floor Tile Installation Systems Using the Robinson-Type Floor Tester |
| ASTM C648 |
Test Method for Breaking Strength of Ceramic Tile |
| ASTM C1027 |
Test Method for Determining Visible Abrasion Resistance of Glazed Ceramic Tile |
| ASTM C1028 |
Test Method for Static Coefficient of Friction (superseded by ANSI A326.3 for slip resistance) |
| ASTM F710 |
Practice for Preparing Concrete Floors to Receive Resilient Flooring (moisture-test reference for membrane selection) |
| ASTM C840 / ASTM C1178 / ASTM C1325 |
Backer Board and Cementitious Backer Unit Specifications |
| TCNA Handbook |
TCNA Handbook for Ceramic, Glass, and Stone Tile Installation (method designations and movement-joint guideline EJ171) |
| IBC |
International Building Code (current edition adopted by jurisdiction) |
2.1All materials, testing, and installation shall comply with the latest edition adopted by the Authority Having Jurisdiction for each of the following referenced standards.
2.2Where the contract documents, a referenced standard, the TCNA Handbook method called out, or the manufacturer'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.
2.3The Contractor shall follow the manufacturer's written installation instructions and the cited TCNA method in addition to this standard.
NOTE For tile, the manufacturer's written installation instructions and the cited TCNA method are not merely advisory — together they define the tested system and the conditions under which the product and installation warranties are valid. ANSI A137.1 is the foundational material specification that classifies tile by type and by water absorption (measured per ASTM C373) and is referenced by every major tile manufacturer; the TCNA Handbook is the recognized source of tested installation methods, identified by method designation (for example a generic floor method or a wet-area wall method), and the method called out in the contract documents defines the tested assembly. The TCNA movement-joint guideline EJ171 governs the location and detailing of movement joints and is the single most frequently ignored requirement in tile work; omitting the movement joints EJ171 requires is the leading cause of tenting and cracking in large tile floors. (2.4)
3 Submittals
3.1 Action Submittals
3.1.1The Contractor shall submit the following for the Architect's review prior to procurement and installation:
- Product data for each tile, identifying the governing tile type per ANSI A137.1, the water-absorption classification per ASTM C373, the nominal size and thickness, the surface finish, the abrasion (PEI) rating where glazed, and the breaking strength
- Product data for each setting material, membrane, grout, and accessory, identifying the governing ANSI specification (for example A118.4 modified dry-set mortar, A118.10 waterproof membrane, A118.6 or A118.7 cement grout, A118.3 epoxy), and a written statement that the selected mortar, membrane, and grout are compatible with the specified tile and substrate and are approved for the service condition
- The TCNA Handbook method designation proposed for each tile location, identifying the substrate, membrane, bonding mortar, and movement-joint treatment
- Samples of each tile in the full range of colors, sizes, and finishes specified, of sufficient quantity to show the range of shade variation, and grout color samples cured to represent the installed appearance
- Slip-resistance (DCOF) test data per ANSI A326.3 for each floor tile, identifying the use classification for which the value qualifies the tile
- Shop drawings showing tile layout, setting-out lines, pattern, the location of every movement and perimeter joint, transitions, trim and edge profiles, and large-format or gauged-panel jointing, coordinated with the finish plans, elevations, and details
- For substrate moisture-sensitive membrane selection over slabs on or below grade, the substrate moisture test result and the basis for the membrane selected
☐ Product data — each tile (type, ASTM C373 classification, size, finish, PEI, breaking strength)
☐ Product data — setting materials, membranes, grout, accessories (with ANSI designation and compatibility statement)
☐ TCNA Handbook method designation per location
☐ Samples — tile (full color/size/finish and shade range) and cured grout colors
☐ DCOF slip-resistance data per ANSI A326.3 (floor tile)
☐ Shop drawings — layout, movement joints, transitions, trim profiles
☐ Substrate moisture test result (membrane basis, slabs on/below grade)
3.1.2Installation shall not begin until the setting-material compatibility statement and, where applicable, the substrate moisture report have been submitted and reviewed.
NOTE The substrate condition determines both the membrane requirement and the bonding-mortar selection. (3.1.3)
3.2 Closeout Submittals
- Manufacturer warranty documentation for the tile and setting materials, executed in the Owner's name where the manufacturer offers an owner-registered warranty
- Maintenance instructions describing recommended cleaning agents, sealing requirements (for unglazed and porous tile and for cementitious grout), and prohibited cleaners for each tile and grout type
- Attic-stock transmittal documenting the quantity, product, color, size, and shade/caliber lot of spare tile and grout delivered to the Owner
☐ Manufacturer warranty documentation for tile and setting materials (executed in Owner's name where offered)
☐ Maintenance instructions (recommended cleaning agents, sealing requirements, prohibited cleaners)
☐ Attic-stock transmittal (quantity, product, color, size, shade/caliber lot of spare tile and grout)
4 Quality Assurance
4.1 Installer Qualifications
○ Credentialed large-format / gauged-panel installer required (panels/slabs or tile with any edge over 15 in)
○ Experienced commercial tile installer (standard-format tile)
○ Not applicable — small-format / mosaic only
4.1.1Tile shall be installed by an installer with documented experience in commercial installations of the specific tile type and method required.
4.1.2Large-format tile, gauged porcelain panels and slabs, and tested wet-area and membrane assemblies shall be installed by mechanics trained in the specific method.
4.1.3The Contractor should employ installers credentialed under a recognized industry program (such as the Certified Tile Installer or Advanced Certifications for Tile Installers programs) for large-format and gauged-panel work.
4.1.4The Contractor shall not assign large-format or gauged-panel work to labor experienced only in small-format tile.
NOTE Large-format tile and gauged panels are unforgiving of substrate irregularity and of inadequate mortar coverage; lippage and hollow-sounding voids that would be tolerable in small mosaic become installation defects in large units, and handling a thin gauged slab without the correct frames and tooling cracks it before it reaches the wall. (4.1.5)
4.2 Mock-Up
○ Yes — install a representative area of each tile type, including a movement joint, a trim/edge condition, and a wet-area detail where applicable
○ No
4.2.1Where a mock-up is required, the Contractor shall install a representative area of each tile type and pattern at a location directed by the Architect, including at least one movement or perimeter joint, one trim or edge condition, one internal or external corner, and one transition to an adjacent finish, and a wet-area detail (curb, drain, or cove) where wet-area tile is specified.
4.2.2The mock-up shall remain available for comparison throughout the work.
NOTE The mock-up establishes the accepted standard for shade range, lippage, joint width, grout color and tooling, and trim detailing. (4.2.3)
4.3 Lippage and Joint Acceptance
○ 1/32 in plus inherent warpage (joints under 1/4 in, rectified tile)
○ 1/16 in plus inherent warpage (joints 1/4 in and wider)
○ Per ANSI A108 for the joint width and tile type
4.3.1Lippage shall not exceed the allowance of ANSI A108 for the grout-joint width and tile type, plus the tile's inherent warpage as permitted by ANSI A137.1.
4.3.2The grout-joint width shall be not less than the minimum the tile's edge and warpage warrant.
NOTE Lippage — the difference in elevation between the edges of two adjacent tiles — is governed by both the flatness of the substrate and the warpage of the tile, and it becomes more conspicuous and more difficult to control as tile size increases and joint width decreases; this is why large-format tile demands a flatter substrate and a minimum joint width. Running a hairline joint with a tile that has any edge variation guarantees visible lippage. (4.3.3)
4.4 Pre-Installation Conference
4.4.1Before installation begins, the Contractor shall hold a pre-installation conference with the Architect and the tile installer to review the substrate condition and flatness, the moisture condition where membranes are moisture-sensitive, the TCNA method and setting materials selected, the layout and pattern, the movement-joint plan, the grout and sealing requirements, and the environmental conditions in the space.
NOTE Most tile disputes trace to a condition that was known but not acted upon before setting — a substrate out of flatness tolerance, a structural joint not carried up as a movement joint, or an incompatible mortar-and-tile combination. The conference exists to surface and resolve those conditions before any tile is set. (4.4.2)
5 Environmental and Service Conditions
5.1 Service Environment Classification
NOTE The service environment determines the tile water-absorption class, the slip-resistance requirement, the membrane requirement, the mortar and grout selection, and the freeze-thaw and chemical-resistance requirements. (5.1.1)
Interior dry — floors and walls not regularly wetted
Interior wet — restrooms, kitchens, shower/tub surrounds, food service
Interior heavy-duty / commercial floor — high traffic, rolling loads
Exterior, freeze-thaw exposed — protected exterior floors and walls
Chemical-exposure — laboratory, industrial, commercial kitchen with aggressive agents
5.1.2The service environment shall be established for each tile location before materials are selected.
5.1.3The Contractor shall confirm the service classification for each location from the contract documents before selecting materials.
5.1.4Ceramic tile in the semi-vitreous or non-vitreous range shall not be used where freeze-thaw cycling can occur.
NOTE Interior dry applications tolerate the broadest range of tile and the simplest setting systems; interior wet applications require a waterproof or water-resistant assembly, slip-resistant floor tile, and backer board rather than standard gypsum board behind wall tile; exterior and freeze-thaw applications require impervious (porcelain) tile, because a tile that absorbs water will spall when that water freezes; chemical-exposure environments require epoxy setting materials and grout and a chemical-resistant tile body; a material selection valid for one environment is a defect in another. (5.1.5)
5.2 Temperature During Installation and Cure
5.2.1The 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.
NOTE 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 likewise have a temperature window for working time and cure. Tile set or grouted outside the temperature window, or exposed to water or traffic before cure, debonds or cracks at the bond line, and this is a frequent and avoidable early failure. (5.2.2)
5.3 Substrate Moisture (Membrane Selection over Slabs)
○ Bonded waterproof membrane (ANSI A118.10) over slab — wet areas and moisture-sensitive assemblies
○ Vapor-managing / moisture-tolerant assembly with cementitious mortar — no moisture-sensitive layers
○ Standard thin-set over sound dry slab — interior dry above-grade only
5.3.1Where tile 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, debonding, or staining through the assembly.
5.3.2Where the assembly includes a moisture-sensitive membrane, organic adhesive, or moisture-sensitive tile, the substrate moisture shall be measured (the relative-humidity method of ASTM F2170 referenced by ASTM F710 being the recognized measure) and the membrane and setting materials selected for the measured condition.
NOTE Unlike resilient flooring, tile bonded with cementitious mortar tolerates substantial substrate moisture and does not require the strict relative-humidity limits of a resilient floor; however, residual slab moisture and alkalinity migrating through the assembly can produce efflorescence in cementitious grout, can debond moisture-sensitive membranes and adhesives, and can stain moisture-sensitive tile and stone. (5.3.3)
5.4 Lighting for Inspection
5.4.1Permanent or equivalent temporary lighting shall be operating during installation and inspection so that lippage, shade variation, grout-joint alignment, hollow-bonded areas, and surface defects can be evaluated under realistic conditions.
5.4.2The 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 where specified.
NOTE Tile is frequently accepted under raking construction lighting that either exaggerates or conceals lippage, which is why the lighting condition for inspection must be controlled. (5.4.3)
6 Tile Products
6.1 Tile Type and Water-Absorption Classification
Porcelain tile — impervious, water absorption 0.5% or less (ASTM C373)
Ceramic / glazed wall tile — non-vitreous to semi-vitreous, walls and interior dry floors
Quarry tile — unglazed, extruded, commercial floors and food service
Glazed ceramic floor tile — vitreous to semi-vitreous, interior floors
Mosaic tile — porcelain or glass, mounted on sheets
Gauged porcelain tile panel / slab (ANSI A137.3)
6.1.1The tile type shall be selected for the use, traffic, exposure, and maintenance expectations of each space and shall be indicated in the finish schedule. 6.1.2Porcelain tile shall comply with ANSI A137.1 with a water absorption of 0.5 percent or less per ASTM C373 where used in exterior, freeze-thaw, or submerged service.
6.1.3Tile water-absorption classification shall be documented per ASTM C373 and shall be appropriate to the service environment.
NOTE The tile type and its water-absorption classification per ASTM C373, as classified by ANSI A137.1, determine the appropriate service environment, the freeze-thaw suitability, the strength, and the maintenance regimen. (6.1.4)
NOTE Porcelain tile, defined by ANSI A137.1 as impervious with a water absorption of 0.5 percent or less measured per ASTM C373, is the dominant commercial tile because its low absorption makes it dense, strong, frost-resistant, and stain-resistant, and it is the only common tile suitable for exterior and freeze-thaw service. The ASTM C373 classification ranges — impervious at 0.5 percent or less, vitreous from 0.5 to 3 percent, semi-vitreous from 3 to 7 percent, and non-vitreous from 7 to 20 percent — directly govern where a tile may be used; a non-vitreous glazed wall tile is correct on an interior dry wall and a defect on an exterior floor. Quarry tile is an unglazed extruded tile valued for its slip resistance and durability in commercial kitchens and food-service floors. Mosaic tile, mounted on sheets, is used for small-module floors and walls and for its slip resistance from the high proportion of grout joints. Gauged porcelain tile panels and slabs, governed by the separate material standard ANSI A137.3 and installation standard ANSI A108.19, are large thin porcelain units one square meter or larger that require their own setting methods, tooling, and substrate flatness and are not interchangeable in installation with conventional tile. (6.1.5)
Mosaic — nominal 2 in or smaller
Small format — nominal 4 in to under 8 in
Standard format — nominal 8 in to under 15 in
Large format — any edge 15 in and over
Plank — long rectangular (wood-look) format
Gauged panel / slab — 1 m² and larger
As scheduled
NOTE Tile format drives the substrate flatness requirement, the minimum mortar coverage, the trowel size, and the lippage control. Large-format tile (any edge 15 inches and over) and gauged panels require a flatter substrate, a larger-notch or flat-and-back-buttered trowel to achieve full coverage, and frequently a tighter lippage-control system, because a large rigid unit will rock on, and telegraph, any substrate high spot or coverage void. (6.2.2)
6.3 Surface Finish and Abrasion Resistance
○ Glazed — gloss
○ Glazed — matte / satin
○ Unglazed — through-body (porcelain, quarry)
○ Polished
○ Textured / structured (slip-resistant)
PEI III — light to moderate commercial floors
PEI IV — moderate to heavy commercial floors
PEI V — heavy commercial and institutional floors
Not applicable — wall tile or through-body unglazed
6.3.1For glazed floor tile, the visible abrasion resistance class determined per ASTM C1027 (commonly cited as the PEI class) shall be appropriate to the traffic.
6.3.2Where a polished floor is specified in a circulation area, the slip-resistance requirement shall still be met.
NOTE The glaze and surface texture affect appearance, slip resistance, cleanability, and abrasion durability. A Class III tile suited to a residential or light-commercial floor will show traffic wear in a commercial corridor, where Class IV or V is appropriate. Polished porcelain is attractive but reduces slip resistance and shows wear and scratching in high traffic. Through-body unglazed porcelain and quarry tile carry no glaze to wear through and are well suited to the highest-traffic floors. (6.3.3)
6.4 Slip Resistance
0.420.6
0.420.50.6
Default: 0.42 DCOF
6.4.1The dynamic coefficient of friction of floor tile shall be measured per ANSI A326.3 (the test method referenced by ANSI A137.1) and shall meet the minimum for the applicable use classification.
6.4.2Ramps, shower floors, pool decks, commercial kitchens, and entries subject to tracked-in water require classification-specific values and shall not be defaulted to the level-interior-wet minimum.
NOTE ANSI A137.1 establishes a minimum DCOF of 0.42 for tile in a level interior space intended to be walked upon when wet; wetter, sloped, and more demanding classifications in the 2022 revision of ANSI A326.3 require higher values, and the test result is meaningful only for the use classification under which it was reported. Slip resistance is a property of the tile surface as installed and as maintained — a polish, a coating, or worn or contaminated conditions change the result — and the DCOF value alone does not predict whether a slip will occur; it provides a comparative basis for selecting a surface appropriate to the wet, sloped, or contaminated condition expected. (6.4.3)
6.5 Breaking Strength
250 lbf — wall tile minimum (ANSI A137.1)
250 lbf — floor tile under 6 in (ANSI A137.1 minimum)
Per ANSI A137.1 for tile type and size
6.5.1Floor tile shall meet the minimum breaking strength of ANSI A137.1 for its type and size, measured per ASTM C648.
6.5.2The breaking strength shall be coordinated with the anticipated load where heavy rolling or point loads occur.
NOTE Breaking strength is the tile's resistance to flexural fracture and is most relevant on floors with concentrated or rolling loads and on tile spanning a substrate that is not fully supported; the most common cause of floor-tile fracture in service, however, is not inadequate breaking strength but inadequate mortar coverage that leaves the tile bridging a void. (6.5.3)
7 Setting Materials
7.1 Bonding Mortar Type
Modified dry-set cement mortar (ANSI A118.4) — general porcelain and ceramic, floors and walls
Improved modified dry-set cement mortar (ANSI A118.15) — large-format, gauged panels, demanding bond
Dry-set cement mortar (ANSI A118.1) — absorptive tile over cured mortar bed
Epoxy adhesive / mortar (ANSI A118.3) — chemical exposure and high-bond applications
Organic adhesive (ANSI A136.1) — interior dry wall tile, limited size
7.1.1The bonding (setting) mortar shall be selected for the tile type, the substrate, and the service environment.
7.1.2Bonding mortar shall comply with the governing ANSI A118 specification for the type selected and shall be approved by the tile manufacturer for the specific tile and substrate.
7.1.3Epoxy setting material conforming to ANSI A118.3, where used, shall be installed per ANSI A108.6.
7.1.4Organic adhesive shall not be used on floors, in wet areas, or with tile exceeding the size the adhesive is rated for.
NOTE Mortar selection is not interchangeable: a dry-set mortar correct for absorptive ceramic over a cured mortar bed will not reliably bond impervious porcelain, and a mortar that lacks the polymer modification of A118.4 or A118.15 will not develop adequate bond to a low-absorption porcelain on a wall. (7.1.5)
NOTE Modified dry-set cement mortar conforming to ANSI A118.4 is the default for the great majority of commercial porcelain and ceramic installations on floors and walls, because its polymer modification develops the bond strength that impervious porcelain requires. Improved modified dry-set mortar conforming to ANSI A118.15 provides higher bond and the non-sag and coverage characteristics needed for large-format tile, gauged porcelain panels and slabs, and demanding vertical and overhead work. Unmodified dry-set mortar conforming to ANSI A118.1 is appropriate for absorptive tile over a cured Portland cement mortar bed. Epoxy setting material conforming to ANSI A118.3 is required where chemical resistance or the highest bond strength is needed — commercial kitchens, laboratories, and industrial floors. Organic adhesive (mastic) conforming to ANSI A136.1 is limited to interior dry walls with tile within the size the adhesive is rated for, because it does not cure to the strength or moisture tolerance other applications demand. (7.1.6)
7.2 Crack-Isolation Membrane
○ 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
7.2.1A 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 tile.
7.2.2A crack-isolation membrane shall not be substituted for the movement joints required by EJ171.
NOTE A crack in a concrete substrate transmits directly into bonded tile unless a crack-isolation membrane uncouples the tile from the substrate movement; ANSI A118.12 recognizes two performance levels by the crack width the membrane bridges. A crack-isolation membrane addresses minor in-plane movement only; it does not bridge structural or moving joints, which must be carried through the tile as movement joints regardless of any membrane. (7.2.3)
7.3 Waterproof Membrane
○ Required — showers, wet areas, exterior, and over occupied space
○ Required at shower receptors and pans only
○ Not required — interior dry application
7.3.1A 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 tile assembly over occupied or moisture-sensitive space.
7.3.2Where a single membrane is selected to serve both the waterproofing and crack-isolation functions, the Contractor shall verify that it is certified to both ANSI A118.10 and ANSI A118.12.
NOTE Tile and cementitious grout are water-resistant but not waterproof — water passes through grout joints and through the assembly over time — so a continuous bonded waterproof membrane behind and beneath wet-area tile is what actually keeps water out of the structure. Many ANSI A118.10 membranes also satisfy the crack-isolation requirements of A118.12, in which case a single membrane serves both functions. (7.3.3)
7.4 Backer Board for Wall Assemblies
Cementitious backer unit (ANSI A118.9 / ASTM C1325) — wet-area walls
Coated glass-mat water-resistant gypsum backer — limited wet exposure
Bonded waterproof membrane over backer — showers and steam
Standard gypsum board — interior dry walls only
7.4.1Tile on framed walls in wet areas shall be set over a cementitious backer unit or an approved water-resistant backer, not over standard gypsum board.
7.4.2Showers and steam rooms shall additionally receive a bonded waterproof membrane.
7.4.3The wall backing shall be coordinated with Gypsum Board Assemblies so that the framing, fastening, and joint treatment of the backer are correct for tile. 7.4.4Interior dry walls may receive tile over standard gypsum board set with an appropriate adhesive or mortar.
NOTE Standard gypsum board deteriorates when repeatedly wetted and loses its ability to hold tile; this is one of the most common causes of wet-area wall-tile failure and is entirely avoided by specifying the correct backer. (7.4.5)
8 Grout
8.1 Grout Type
High-performance cement grout (ANSI A118.7) — standard commercial floors and walls
Standard cement grout (ANSI A118.6) — interior light-duty
Epoxy grout (ANSI A118.3) — chemical exposure, food service, stain resistance
As scheduled
8.1.1The grout shall be selected for the joint width, the service environment, the stain- and chemical-resistance requirement, and the cleanability, and shall comply with the governing ANSI specification.
8.1.2Cementitious grout shall comply with ANSI A118.7 (high-performance) or ANSI A118.6 (standard) as scheduled.
8.1.3Epoxy grout shall comply with ANSI A118.3 and shall be used where chemical or maximum stain resistance is required.
8.1.4Cementitious grout should be sealed where stain resistance matters, whereas epoxy grout is inherently non-absorptive and does not require sealing.
NOTE High-performance cement grout conforming to ANSI A118.7 is the default for commercial floors and walls because it resists shrinkage cracking and water absorption better than standard cement grout and does not require a separate latex additive at mixing. Standard cement grout conforming to ANSI A118.6 is suited to interior light-duty applications. Epoxy grout conforming to ANSI A118.3 is required where chemical resistance, the maximum stain resistance, or a non-absorptive joint is needed — commercial kitchens, food-processing areas, laboratories, and high-stain public restrooms — and it is more difficult and more time-sensitive to install, which is why it is reserved for applications that justify it rather than used universally. (8.1.5)
8.2 Grout Joint Width
0.06250.375
0.06250.1250.18750.250.375
Default: 0.1875 in
8.2.1The grout-joint width shall be selected for the tile size, the tile edge type, and the tile warpage, and shall not be less than the minimum the tile warrants.
NOTE Industry practice sets the minimum joint width at not less than three times the average variation in facial dimension of the tile, and for rectified tile a minimum nominal joint of about 1/16 inch and for non-rectified (cushion-edge) tile a wider joint; running a joint narrower than the tile's dimensional and warpage variation produces visible lippage and uneven joints. Wider joints accommodate larger dimensional variation and provide slip resistance from the grout itself, but very wide cementitious joints are more prone to shrinkage cracking and require a sanded high-performance grout. (8.2.3)
8.3 Grout Sealing
○ Penetrating sealer applied to cementitious grout after cure — stain-prone areas
○ No sealer — epoxy grout (non-absorptive)
○ No sealer required for the application
8.3.1Where cementitious grout is used in stain-prone areas — restrooms, food service, public floors — a penetrating sealer shall be applied to the cured grout to reduce absorption and staining, following the grout manufacturer's required cure period before sealing.
8.3.2Where grout is sealed, the sealer shall be documented in the maintenance instructions.
NOTE Epoxy grout is non-absorptive and does not require sealing. Sealer applied before the grout has cured traps moisture and prevents proper hydration. Sealer is part of the maintenance basis. (8.3.3)
9 Movement Joints
9.1 Movement Joint Design
9.1.1Movement joints shall be provided throughout tile work in accordance with the TCNA movement-joint guideline EJ171, and their locations shall be shown on the tile shop drawings and details before any tile is set. 9.1.2Interior 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.
9.1.3Exterior installations, and interior installations exposed to direct sunlight or to moisture and wide temperature swings, shall have field movement joints at the closer spacing EJ171 establishes for those exposures, commonly on the order of 8 to 12 feet in each direction.
9.1.4The closer of the EJ171 requirement and any project-specific requirement governs.
9.1.5Perimeter movement joints shall be provided where tile abuts restraining surfaces, walls, columns, curbs, and dissimilar floors.
9.1.6Movement joints shall be carried through over every structural joint, cold joint, and control joint in the substrate and at every change in substrate plane or material.
9.1.7Movement joints shall be left open of grout and filled with the specified sealant or fitted with a preformed movement-joint profile.
NOTE Movement joints are open, sealant-filled, or preformed-profile joints — not grout — that allow the tile assembly to expand, contract, and accommodate substrate movement without building the compressive stress that causes tile to tent, debond, and crack. EJ171 requires movement joints at the perimeter of every tiled area where it abuts restraining surfaces, over every structural and cold joint and control joint in the substrate, at changes in substrate plane or material, at internal corners, and in the field of the tile at the spacing the guideline establishes for the exposure. Omitting field movement joints in a large floor is the leading cause of catastrophic tile failure; thermal and moisture expansion with no place to go will lift the tile off the floor in a ridge. Grout is rigid and does not function as a movement joint. (9.1.8)
9.2 Movement Joint Sealant
○ Field-applied elastomeric sealant over backer rod / bond breaker
○ Preformed metal or rigid movement-joint profile
○ Preformed flexible movement-joint profile
9.2.1Movement 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.
9.2.2The sealant or profile shall be capable of the movement the joint will see and shall be compatible with the tile edge and the grout.
NOTE A sealant that bonds to the joint bottom as well as the sides cannot accommodate movement and tears, which is why the bond breaker is essential. (9.2.3)
10 Substrate Preparation
10.1 General Substrate Requirements
10.1.1The 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.
10.1.2Concrete 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 tile is set.
10.1.3The Contractor shall verify the substrate condition before installation.
NOTE Thin-set mortar bonds mechanically to the substrate and cannot grip a sealed or contaminated surface. Setting tile over a noncompliant substrate transfers a known defect into the finished work and is not a tile defect. (10.1.4)
10.2 Flatness Tolerance
○ 1/4 in in 10 ft and 1/16 in in 1 ft (tile with all edges under 15 in)
○ 1/8 in in 10 ft and 1/16 in in 2 ft (large-format tile, any edge 15 in and over)
○ Per the requirement for the tile size and method
10.2.1The substrate shall meet the flatness tolerance required for the tile size and method — for tile with all edges under 15 inches, a maximum of 1/4 inch in 10 feet and 1/16 inch in 1 foot, and for large-format tile and gauged panels with any edge 15 inches and over, a maximum of 1/8 inch in 10 feet and 1/16 inch in 2 feet.
10.2.2High spots shall be ground down and low spots filled with a cementitious patching or self-leveling underlayment compatible with the setting system.
NOTE A large rigid unit cannot conform to and will rock on a substrate undulation that a small tile would tolerate, which is why the tolerance tightens for large-format tile; setting large-format tile over a substrate held only to the small-format tolerance is the single most common cause of lippage and hollow-bonded large-format floors. (10.2.3)
10.3 Substrate Type Verification
Concrete slab — cured, sound, profiled
Cementitious backer unit over framing — walls and floors
Cured Portland cement mortar bed
Existing tile / terrazzo (bond-coat or membrane over)
Exterior glue plywood (interior dry, EGP method, ANSI A118.11)
10.3.1The setting system and TCNA method shall match the substrate type.
10.3.2Tile over wood subfloors shall use only methods and materials rated for wood movement — exterior glue plywood with the EGP latex-Portland cement mortar of ANSI A118.11 for interior dry conditions, or a backer board or uncoupling/crack-isolation membrane over a structurally adequate floor.
10.3.3Single-layer wood subfloors that deflect under load shall be stiffened or receive an approved underlayment before tile is set.
NOTE Wood expands, contracts, and deflects with moisture and load and will crack tile bonded directly to it, and tile cracks over a deflecting floor regardless of the mortar. (10.3.4)
11 Installation
11.1 Layout
Straight (stacked / grid)
Running bond / brick (offset limited per tile size)
Diagonal
Herringbone
As detailed on drawings
11.1.1The Contractor shall establish the layout from the control lines and setting-out points shown on the finish plan so that border and cut tiles are balanced and of adequate width, full tiles fall at the most prominent locations, patterns align across the space and through openings, and movement joints fall where the design and EJ171 require. 11.1.2Layout shall be dry-laid and approved before any mortar is spread.
11.1.3Where a running-bond (offset) pattern is used with rectangular and large-format tile, the offset shall be limited as the tile manufacturer and the TCNA recommend — commonly to not more than one-third of the tile length for tile with any edge 15 inches and over.
NOTE A floor set without a planned layout produces slivers at one wall, misaligned grout lines at thresholds, and cut tiles in the most visible locations. A 50-percent offset of a long tile places the center of each tile against the high point of the warped edge of its neighbor and produces unavoidable lippage, which is why a running-bond offset must be limited for large-format and rectangular tile. (11.1.5)
11.2 Mortar Application and Coverage
11.2.1Bonding mortar shall be applied with the trowel notch, the technique, and the open time the mortar and tile require to achieve the specified coverage, and the mortar shall be combed in one direction with directional troweling and the tile set with a slight perpendicular movement to collapse the ridges and eliminate voids.
11.2.2The mortar coverage achieved beneath the tile 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 tile edges and corners and with no voids beneath.
11.2.3Tile 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 tile.
11.2.4Large-format tile and gauged panels shall be back-buttered in addition to combing the substrate to achieve the required coverage.
NOTE Inadequate mortar coverage is the leading cause of tile cracking, debonding, and hollow-sounding floors; a tile bridging a void has no support beneath it and fractures under load, and an edge void at a grout joint admits water and lets the edge break away. The required coverage cannot reliably be achieved on a large unit by combing the substrate alone, which is why large-format tile and gauged panels are also back-buttered. (11.2.5)
11.3 Beating-In and Lippage Control
11.3.1Floor tile shall be beaten in or rolled with a beating block or the manufacturer's tool, and large-format tile shall be set with a mechanical lippage-control (leveling) system where required, to seat the tile fully into the mortar, collapse the ridges, and bring adjacent tile edges into plane within the lippage allowance.
NOTE Mortar ridges that are not collapsed leave voids and produce a hollow floor; adjacent tiles not brought into plane produce lippage that becomes a trip hazard on floors and a conspicuous defect on walls. (11.3.2)
11.4 Grouting
11.4.1Joints shall be cleaned of mortar and debris to a uniform depth before grouting, the grout worked fully into the joints to fill them solid, the excess struck off, and the surface cleaned and tooled to a uniform, slightly concave joint without smearing grout haze onto the tile face.
11.4.2Grouting shall not begin until the bonding mortar has cured for the period the mortar manufacturer requires, typically not less than 24 to 72 hours, so that grouting does not disturb the uncured bond.
11.4.3Joints intended to function as movement joints shall be left open of grout and shall not be filled with grout under any circumstances.
NOTE Grout that is not packed solid into clean joints leaves voids that admit water and break out under traffic; grout haze that is not removed while workable cures onto the tile face and is difficult to remove later. (11.4.4)
11.5 Curing and Protection
11.5.1The completed tile 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 mortar and grout have cured for the period the materials require, typically not less than 7 days for cementitious materials.
11.5.2Floors shall be protected with a breathable covering that does not trap moisture against the tile or transfer color.
11.5.3Heavy construction traffic, rolling loads, and point loads shall be kept off the floor until cure is complete.
NOTE Trafficking or washing tile before the setting bed and grout have cured debonds and cracks the work at the bond line and is a frequent, avoidable early failure. (11.5.4)
12 Field Testing
Light commercial
Moderate commercial
Heavy commercial
Extra-heavy commercial
Residential / per design
12.1.1Where the floor will carry heavy commercial or institutional service — high pedestrian traffic, rolling loads, or institutional duty — the selected installation system (substrate, membrane, mortar, tile, and grout as an assembly) shall be one rated for the service classification of ASTM C627, the Robinson-type floor-tester method used to classify tile installation systems from residential through extra-heavy commercial.
NOTE ASTM C627 evaluates the assembly, not the tile alone, which is why the method, mortar, and substrate matter as much as the tile; selecting a residential-rated assembly for a commercial floor produces a floor that fails under the traffic regardless of the tile's own strength. (12.1.2)
12.2 Bond and Installation Inspection
○ Yes — full-area sounding and visual inspection under permanent lighting
○ No
12.2.1After installation and cure, the tile shall be inspected for full bond, with no hollow-sounding (unbonded) tile, no lippage exceeding the allowance, no cracked or chipped tile, uniform grout joints fully packed and free of voids and haze, correct shade range, and movement joints correctly formed and left open of grout, under the permanent or equivalent lighting.
12.2.2Tile shall be sounded — tapped to detect the hollow ring of an unbonded unit — across the floor; hollow or unbonded tile shall be removed and reset.
12.2.3The Contractor shall confirm by periodic removal of set tile that the required mortar coverage was achieved across the work and not only at the points first inspected.
13 Cleaning and Sealing
13.1After the grout has cured for the period the manufacturer requires, the tile shall be cleaned of grout haze, construction soil, and marks by the method and cleaners the tile and grout manufacturers permit, and prohibited cleaners (such as acids on cementitious grout or polished marble-look porcelain, where the manufacturer prohibits them) shall not be used.
13.2Where cementitious grout in a stain-prone area is to be sealed, the penetrating sealer shall be applied after grout cure following the manufacturer's instructions.
13.3The cleaning agents and sequence shall follow the manufacturer's program and shall be recorded in the maintenance instructions.
NOTE Acid cleaning of cementitious grout before it has cured etches and weakens the joint. (13.4)
14 Delivery, Storage, and Handling
14.1Tile, setting materials, grout, membranes, and accessories shall be delivered in the manufacturer's original unopened packaging with labels intact, identifying product, color, size, and shade/caliber lot.
14.2Tile shall be stored indoors, protected from weather, freezing, and breakage, and shall be kept dry; cementitious setting materials and grout absorb moisture from the air and shall be stored off the floor in a dry space, and material that has hardened, lumped, or exceeded its shelf life shall be discarded.
14.3Gauged porcelain panels and slabs shall be transported, stored, and handled in the manufacturer's frames or A-frames and moved with the suction-cup and frame tooling the manufacturer requires.
14.4All tile for a continuous area should be from the same shade and caliber lot wherever possible.
NOTE Epoxy and polymer components have a limited shelf life and a storage-temperature window below or above which they are damaged; an unsupported thin gauged slab cracks under its own weight; and shade and dimension vary between lots, so a lot change within a single visual field is apparent. (14.5)
15 Warranty
1 year (materials)
Lifetime — limited (porcelain tile body, residential-grade)
As offered by the manufacturer for the products specified
1 year from substantial completion
2 years from substantial completion
15.1The tile and setting-material manufacturers shall warrant their products against manufacturing defects for the period offered, and where a 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.
15.2The Contractor shall warrant the installation — including substrate preparation, membrane and mortar application, mortar coverage, lippage and joint quality, grouting, movement-joint formation, and sealing — against defective workmanship for the project warranty period.
NOTE Manufacturer system warranties are typically void unless the complete tested system — substrate condition, membrane, mortar, grout, and movement joints — was installed in accordance with the manufacturer's instructions and the cited TCNA method, and the installation record (method, materials, and any substrate moisture results) is therefore part of the warranty basis. Failures arising from substrate movement at locations where required movement joints were omitted, from water intrusion where a required waterproof membrane was omitted, from cleaning or maintenance contrary to the manufacturer's instructions, or from loads exceeding the rated installation-system service classification are excluded from both warranties. (15.3)
16 Spare and Extra Materials
16.1The Contractor shall deliver to the Owner spare tile of each type, color, size, and finish installed, and spare grout of each color, in the percentage of installed area stated, in full unopened cartons labeled with the product, color, size, and shade/caliber lot.
16.2Spare material shall be from the same lots as the installed tile and shall be stored by the Owner in a dry, protected location.
NOTE Attic stock allows the Owner to repair damaged areas with tile from the same shade and caliber lot as the original installation, which is essential because later-purchased replacement tile will be from a different lot and will not match in shade or dimension. (16.3)