+---
+title: Portland Cement Plaster and Stucco
+category: Architectural
+toc_depth: 3
+description: >
+ When to use: Portland cement-based plaster (stucco) wall cladding and interior
+ finish systems for commercial, institutional, healthcare, education, multifamily,
+ and residential construction. Covers three-coat hard-coat systems (scratch, brown,
+ finish), two-coat systems over rigid substrates, and one-coat fiber-reinforced
+ proprietary systems applied over metal or fiber-cement lath on wood or steel stud
+ framing, over concrete/masonry backup, and at soffits, including basecoat and finish
+ mixes, aggregate, lath and furring selection and attachment, weather-resistive
+ barrier integration, accessories (weep screeds, control and expansion joints, corner
+ and casing beads), mixing, application, and curing.
+ Not intended for: polymer-based exterior insulation and finish systems (see
+ [[sync/exterior-insulation-and-finish-systems]]); gypsum veneer plaster and gypsum
+ board assemblies (see [[sync/gypsum-board-assemblies]]); primary air and vapor
+ barrier membranes (see [[sync/air-barriers]]); topcoat and elastomeric coatings
+ over cured stucco (see [[sync/exterior-painting]]); ceramic or porcelain tile over
+ a scratch coat (see [[sync/ceramic-tile]]); masonry unit construction and mortar
+ joints; and below-grade waterproofed parging (see [[sync/below-grade-waterproofing]]).
+---
+
+# Scope {toc}
+
+## This standard governs the materials, lath and furring, accessories, mixing, application, and curing of portland cement-based plaster (stucco) for exterior cladding and interior finish. {note}
+
+## Portland cement plaster is a field-applied cementitious cladding built up in successive coats over a rigid base. Its weather performance depends less on the plaster itself than on the assembly behind it: the weather-resistive barrier, the drainage plane, the lath attachment, and the accessories that terminate, drain, and relieve the cladding. This standard treats the stucco as one layer of a coordinated wall assembly and binds the decisions that most often drive moisture and cracking claims. {note}
+
+## Stucco is a reservoir cladding that absorbs and stores water; it is not a barrier system, and the assembly behind it must be designed to drain. {note}
+
+## The three coat-system families covered here are three-coat hard-coat, two-coat over rigid substrates, and one-coat fiber-reinforced proprietary systems. {note}
+
+### Three-coat systems consist of a scratch coat, a brown coat, and a finish coat applied over metal or fiber-cement lath, and are the default for cladding over framed walls. {note}
+
+### Two-coat systems consist of a basecoat (combined scratch and brown) and a finish coat applied directly over a rigid, absorptive substrate such as concrete or concrete masonry. {note}
+
+### One-coat systems are proprietary factory-blended fiber-reinforced basecoats applied at nominal 3/8 in. thickness in a single pass, followed by a finish coat, and are evaluated under a product evaluation report rather than ASTM C926 coat thicknesses. {note}
+
+## The following are outside this standard and are governed elsewhere. {note}
+
+- Polymer-based exterior insulation and finish systems (EIFS) with EPS foam-board base and polymer finish coat: see [[sync/exterior-insulation-and-finish-systems]].
+- Gypsum veneer plaster and gypsum board base assemblies: see [[sync/gypsum-board-assemblies]].
+- Air and vapor barrier membranes as the primary weather-resistive system: see [[sync/air-barriers]]. The weather-resistive barrier behind stucco is coordinated here but specified there.
+- Exterior topcoat and elastomeric coatings over cured stucco: see [[sync/exterior-painting]].
+- Thin-set ceramic or porcelain tile over a scratch coat: see [[sync/ceramic-tile]].
+- Masonry unit construction and mortar joints: not addressed.
+- Below-grade waterproofed parging: see [[sync/below-grade-waterproofing]].
+
+## Coordination with adjacent assemblies is required where stucco terminates against other work. {note}
+
+### Sealant joints at casing beads, control joints, and penetrations shall be specified and detailed under [[sync/joint-sealants]]. {note}
+
+### Cold-formed steel stud framing that receives lath shall comply with [[sync/cold-formed-metal-framing]] for gauge, spacing, and deflection limits. {note}
+
+### Thermal insulation within the wall cavity behind stucco shall be specified under [[sync/building-thermal-insulation]]. {note}
+
+# Referenced Standards {toc}
+
+## Materials, lath and furring, accessories, mixing, application, and curing shall comply with the latest adopted edition of each of the following unless a specific edition is cited or an adopted building code mandates a particular edition. {note}
+
+### Where referenced standards conflict, the more stringent requirement shall govern unless the Architect or Engineer of Record directs otherwise in writing.
+
+| Standard | Title |
+|----------|-------|
+| ASTM C926 | Application of Portland Cement-Based Plaster |
+| ASTM C1063 | Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster |
+| ASTM C847 | Metal Lath |
+| ASTM C897 | Aggregates for Job-Mixed Portland Cement-Based Plasters |
+| ASTM C1861 | Lathing and Furring Accessories, and Fasteners, for Interior and Exterior Portland Cement-Based Plaster |
+| ASTM C1787 | Installation of Fiber-Reinforced Cement Panels Used as Backing for Exterior Portland Cement-Based Plaster |
+| ASTM C1788 | Fiber-Reinforced Cement Panels Used as Backing for Exterior Portland Cement-Based Plaster |
+| ASTM C150/C150M | Portland Cement |
+| ASTM C206 | Finishing Hydrated Lime |
+| ASTM C35 | Inorganic Aggregates for Use in Gypsum Plaster |
+| ASTM C1780 | Installation Methods for Exterior Cement Plaster Accessories |
+| IBC Section 2510 | Lathing and Furring for Cement Plaster (Stucco) |
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following action submittals for review before fabrication, ordering, or installation:
+
+- Product data for portland cement, hydrated lime, aggregate, pre-blended basecoat and finish products, and water-repellent admixtures.
+- Product data for metal lath or fiber-cement panel base, furring, fasteners, and all accessories.
+- Product data for the weather-resistive barrier and any self-adhered flashing.
+- Shop drawings showing control joint and expansion joint layout, accessory locations, weep screed elevations, and termination details at openings and penetrations.
+- A finish coat color and texture schedule keyed to the approved sample panels.
+- Mix design for each job-mixed coat stating cement, lime, and aggregate proportions and water-repellent admixture dosage.
+
+```datasheet
+label: Action submittals required
+type: checkbox
+options:
+ - Cement, lime, aggregate product data
+ - Pre-blended basecoat / finish product data
+ - Water-repellent admixture data
+ - Lath, furring, fastener product data
+ - Accessory product data
+ - Weather-resistive barrier and flashing data
+ - Control / expansion joint and accessory shop drawings
+ - Weep screed elevation details
+ - Finish color and texture schedule
+ - Coat mix designs
+default:
+ - Cement, lime, aggregate product data
+ - Pre-blended basecoat / finish product data
+ - Lath, furring, fastener product data
+ - Accessory product data
+ - Weather-resistive barrier and flashing data
+ - Control / expansion joint and accessory shop drawings
+ - Finish color and texture schedule
+```
+
+### The Contractor shall submit sample panels for each finish coat color and texture prior to production.
+
+### Each sample panel shall be a minimum of 4 ft × 4 ft and shall be built up using the same coats, mix, aggregate, and tools proposed for the work.
+
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following informational submittals:
+
+- Manufacturer installation instructions for proprietary one-coat or pre-blended systems.
+- Product evaluation report (for example an ICC-ES report) for any proprietary system used in lieu of an ASTM C926 prescriptive system.
+- Applicator qualification records demonstrating completed projects of comparable scope.
+- Manufacturer certification that the proposed finish coat is compatible with any specified coating under [[sync/exterior-painting]].
+
+```datasheet
+label: Informational submittals required
+type: checkbox
+options:
+ - Manufacturer installation instructions
+ - Product evaluation report (one-coat / proprietary)
+ - Applicator qualifications
+ - Coating compatibility certification
+default:
+ - Manufacturer installation instructions
+ - Applicator qualifications
+```
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following closeout submittals:
+
+- Maintenance data describing cleaning, recoating, and crack-repair procedures.
+- Record of finish coat color, texture, and source for each elevation to support future repairs.
+- Warranty documentation as required by this standard.
+
+```datasheet
+label: Closeout submittals required
+type: checkbox
+options:
+ - Maintenance data
+ - Finish color / texture / source record
+ - Warranty documentation
+default:
+ - Maintenance data
+ - Finish color / texture / source record
+ - Warranty documentation
+```
+
+# Quality Assurance {toc}
+
+## Plastering quality depends on applicator skill, controlled mixes, and disciplined curing far more than on material selection alone, so qualification and mock-up requirements carry real weight. {note}
+
+### The plastering applicator shall have completed at least three projects of comparable system, scope, and exposure within the preceding five years.
+
+### A mock-up shall be constructed showing the full assembly from substrate through finish coat, including a control joint, an inside and outside corner, a weep screed, and a casing bead at an opening.
+
+### The mock-up shall be reviewed and accepted by the Architect before production plastering begins, and the accepted mock-up shall establish the standard of workmanship, color, and texture for the work.
+
+### The accepted mock-up may remain as part of the permanent work if it is indistinguishable from the surrounding finish and is located within the scope of work.
+
+## Single-source responsibility reduces the interface risk between basecoat, finish, and accessories. {note}
+
+### Basecoat, finish coat, and water-repellent admixture for any proprietary or pre-blended system shall be obtained from a single manufacturer.
+
+### The applicator shall not substitute finish coat products of a different manufacturer for any portion of the work without a new color sample approval.
+
+## Field quality control verifies that the as-built assembly matches the approved mock-up. {note}
+
+### The Contractor shall verify and document weep screed elevation above grade and above paved surfaces before basecoat application.
+
+### The Contractor shall verify weather-resistive barrier layer count, lap direction, and flashing integration before lath installation.
+
+### The Contractor shall verify lath type, fastener type, and fastener spacing against the approved shop drawings before basecoat application.
+
+# Environmental and Service Conditions {toc}
+
+## Portland cement plaster cures by hydration, so application temperature and moisture control directly govern strength and crack resistance. {note}
+
+### Plaster shall not be applied when the ambient or surface temperature is below 4 °C (40 °F) unless enclosure and heat are provided to maintain the minimum temperature throughout application and curing.
+
+### Plaster shall not be applied to a frozen, frost-coated, or sun-heated substrate.
+
+### When ambient temperature exceeds 32 °C (90 °F) or under drying wind, the Contractor shall protect the work and provide moist curing to prevent premature drying of the basecoat.
+
+```datasheet
+label: Minimum application and curing temperature
+type: range
+unit: °C
+min: 4
+max: 10
+step: 1
+default: 4
+```
+
+## The weather-resistive barrier requirement behind stucco varies by climate zone, and getting it wrong is a common source of code non-compliance. {note}
+
+### Over wood-based sheathing, the number of weather-resistive barrier layers shall comply with the adopted edition of IBC Section 2510 for the project climate zone.
+
+### In moist (zone marine C) and marine climate zones, a minimum of two layers of weather-resistive barrier shall be provided over wood-based sheathing where required by IBC Section 2510.
+
+### A single layer of weather-resistive barrier specified where the code requires two layers shall be corrected before lath installation.
+
+```datasheet
+label: Weather-resistive barrier configuration over wood-based sheathing
+type: radio
+options:
+ - Single layer Grade D building paper (dry climate zones)
+ - Two layers Grade D building paper (moist / marine climate zones)
+ - Self-adhered water-resistive barrier membrane
+default: Two layers Grade D building paper (moist / marine climate zones)
+```
+
+# Coat Systems and Thickness {toc}
+
+## Coat thickness and the number of coats are the backbone of stucco performance; thin or skipped coats are a direct cause of cracking and water intrusion. {note}
+
+### The coat system shall be selected for the substrate: three-coat over metal or fiber-cement lath on framing, two-coat over rigid absorptive substrates, and one-coat only where covered by a product evaluation report.
+
+```datasheet
+label: Coat system
+type: radio
+options:
+ - Three-coat (scratch, brown, finish) over lath
+ - Two-coat (basecoat, finish) over rigid substrate
+ - One-coat fiber-reinforced proprietary system
+default: Three-coat (scratch, brown, finish) over lath
+```
+
+### For a three-coat system over metal lath, the nominal total basecoat thickness measured from the face of the lath shall be 7/8 in., with the scratch and brown coats proportioned per ASTM C926.
+
+### For a two-coat system over a rigid absorptive substrate, the nominal total basecoat thickness shall be 1/2 in. unless the substrate manufacturer requires greater thickness.
+
+### The finish coat shall be a nominal 1/8 in. thick unless a thinner factory-blended finish is used in accordance with its product data.
+
+```datasheet
+label: Nominal total basecoat thickness (three-coat over metal lath)
+type: range
+unit: in
+min: 0.75
+max: 1.0
+step: 0.125
+default: 0.875
+```
+
+```datasheet
+label: Nominal finish coat thickness
+type: range
+unit: in
+min: 0.0625
+max: 0.25
+step: 0.0625
+default: 0.125
+```
+
+## Curing intervals between coats allow shrinkage to occur before the next coat locks the surface, which is why fast-tracking the schedule causes cracking claims. {note}
+
+### The scratch coat shall cure for a minimum of 48 hours before the brown coat is applied, with moist curing as required by ambient conditions.
+
+### The brown coat shall cure for a minimum of 7 days before the finish coat is applied.
+
+### Each coat shall be moist-cured as required by ASTM C926 to develop strength and limit shrinkage cracking.
+
+```datasheet
+label: Minimum cure interval, scratch to brown coat
+type: range
+unit: h
+min: 48
+max: 72
+step: 12
+default: 48
+```
+
+```datasheet
+label: Minimum cure interval, brown coat to finish coat
+type: range
+unit: d
+min: 7
+max: 14
+step: 1
+default: 7
+```
+
+# Materials {toc}
+
+## Material selection binds the mix chemistry; loose specifications let contractors over-sand weak coats or under-lime brittle coats. {note}
+
+### Portland cement shall comply with ASTM C150/C150M, Type I or Type II.
+
+```datasheet
+label: Portland cement type
+type: radio
+options:
+ - Type I
+ - Type II
+ - Type I/II
+default: Type I/II
+```
+
+### Hydrated lime used as a plasticizer shall comply with ASTM C206, Type S.
+
+### Aggregate for job-mixed basecoat and finish plaster shall comply with ASTM C897 for gradation and cleanliness.
+
+### Aggregate for interior plaster basecoats in mixed-use gypsum assemblies shall comply with ASTM C35 where applicable.
+
+### Water shall be potable and free of deleterious amounts of acids, alkalis, salts, and organic material.
+
+## Basecoat mix proportions {toc}
+
+### The basecoat mix shall be either a factory pre-blended bagged product or job-mixed to the cement-lime-aggregate proportions of ASTM C926 Table 1 for the selected base. {note}
+
+### Where the basecoat is job-mixed, the cement, lime, and aggregate proportions for the scratch and brown coats shall be stated in the approved mix design and shall conform to ASTM C926 Table 1.
+
+### Aggregate shall not exceed the maximum volume per part of cementitious material permitted by ASTM C926 for the coat being mixed.
+
+```datasheet
+label: Basecoat mix source
+type: radio
+options:
+ - Factory pre-blended bagged basecoat
+ - Job-mixed per ASTM C926 Table 1
+default: Factory pre-blended bagged basecoat
+```
+
+```datasheet
+label: Lightweight aggregate basecoat
+type: radio
+options:
+ - Standard sand aggregate
+ - Lightweight EPS / perlite aggregate
+default: Standard sand aggregate
+```
+
+## Finish coat {toc}
+
+### The finish coat type shall be selected for the project appearance, exposure, and recoating intent. {note}
+
+### A portland cement sand finish coat shall be job-mixed or pre-blended and may be integrally colored or left unpigmented for field coating under [[sync/exterior-painting]].
+
+### An acrylic-modified factory-blended finish coat shall be integrally colored and applied in accordance with its product data.
+
+### Where integral color is specified, the finish coat color shall match the approved sample panel for the corresponding elevation.
+
+```datasheet
+label: Finish coat type
+type: radio
+options:
+ - Portland cement sand finish, integrally colored
+ - Portland cement sand finish, unpigmented for field coating
+ - Acrylic-modified factory-blended color finish
+ - Lime putty trowel finish
+default: Acrylic-modified factory-blended color finish
+```
+
+```datasheet
+label: Integral color in finish coat
+type: radio
+options:
+ - Integrally colored finish coat
+ - Unpigmented finish coat, painted under exterior-painting standard
+default: Integrally colored finish coat
+```
+
+### The finish texture shall be specified by name and confirmed by an approved sample panel; texture names alone without a sample shall not be relied upon for acceptance. {note}
+
+```datasheet
+label: Finish texture
+type: radio
+options:
+ - Smooth trowel
+ - Sand float
+ - Dash
+ - Skip trowel
+ - Cat face
+default: Sand float
+```
+
+## Water-repellent admixture improves the cladding's resistance to absorption but is not a substitute for the drainage plane. {note}
+
+### Where a water-repellent admixture is specified, it shall be added at the manufacturer's dosage and shall be compatible with the finish coat and any specified coating.
+
+```datasheet
+label: Integral water-repellent admixture
+type: radio
+options:
+ - None
+ - Basecoat only
+ - Basecoat and finish coat
+default: Basecoat and finish coat
+```
+
+# Lath, Furring, and Plaster Base {toc}
+
+## The plaster base anchors the stucco; lath type and attachment determine whether the cladding deflects and cracks under load. {note}
+
+### The plaster base shall be selected for the substrate and exposure: expanded metal lath, welded wire lath, fiber-cement backer panel, or direct application over concrete or concrete masonry.
+
+```datasheet
+label: Plaster base / lath type
+type: radio
+options:
+ - Expanded metal diamond-mesh lath
+ - Rib metal lath
+ - Welded wire lath
+ - Fiber-cement backer panel
+ - Direct over concrete / CMU
+default: Expanded metal diamond-mesh lath
+```
+
+### Expanded metal lath shall comply with ASTM C847.
+
+### Self-furred metal lath shall be used over a solid substrate so that the lath is held off the weather-resistive barrier to allow full embedment.
+
+```datasheet
+label: Metal lath weight
+type: radio
+options:
+ - 2.5 lb/yd²
+ - 3.4 lb/yd²
+default: 3.4 lb/yd²
+```
+
+### Fiber-cement panels used as a nonmetallic plaster base shall comply with ASTM C1788 and shall be installed in accordance with ASTM C1787.
+
+## Lath and furring installation shall comply with ASTM C1063, which governs the fastener schedule, stud spacing limits, and accessory installation. {note}
+
+### Lath shall be installed with the long dimension of the sheet across the supports and with end and side laps as required by ASTM C1063.
+
+### Lath shall be attached to framing with fasteners of the type, length, and corrosion resistance required by ASTM C1063 and ASTM C1861.
+
+### Fasteners shall penetrate framing members and shall be spaced not more than the maximum permitted by ASTM C1063 for the support type.
+
+```datasheet
+label: Lath fastener spacing (max), at supports
+type: range
+unit: in
+min: 6
+max: 7
+step: 1
+default: 6
+```
+
+## Stud spacing limits imposed by ASTM C1063 prevent over-deflection of the lath and the basecoat cracking that follows. {note}
+
+### For exterior plaster over cold-formed steel framing, stud spacing shall not exceed the limit set by ASTM C1063 for the framing gauge, with 16 in. on center maximum for 20-gauge studs and 24 in. on center maximum for 18-gauge studs.
+
+### Framing deflection under design wind load shall be limited to L/360 measured at the lath to control finish cracking.
+
+```datasheet
+label: Stud spacing (exterior, cold-formed steel)
+type: radio
+options:
+ - 16 in. o.c. (20-gauge)
+ - 24 in. o.c. (18-gauge or heavier)
+default: 16 in. o.c. (20-gauge)
+```
+
+```datasheet
+label: Framing deflection limit at lath
+type: radio
+options:
+ - L/360
+ - L/600
+default: L/360
+```
+
+# Accessories {toc}
+
+## Accessories terminate, drain, and relieve the cladding; their selection and placement are where most stucco moisture defects originate. {note}
+
+### Weep screeds, control joints, expansion joints, corner beads, and casing beads shall comply with ASTM C1861 for material and corrosion resistance, and shall be installed in accordance with ASTM C1063 and ASTM C1780.
+
+```datasheet
+label: Accessory base metal / corrosion resistance
+type: radio
+options:
+ - Galvanized steel
+ - Zinc alloy
+ - PVC
+default: Zinc alloy
+```
+
+## Weep screed {toc}
+
+### A weep screed is the drainage and termination accessory at the base of an exterior stucco wall over framing; omitting or blocking it is among the leading causes of moisture intrusion claims. {note}
+
+### A weep screed shall be installed at the base of all exterior stucco walls over wood or steel framing.
+
+### The weep screed shall be located a minimum of 4 in. (102 mm) above finished grade and a minimum of 2 in. (51 mm) above paved or hardscape surfaces.
+
+### The weather-resistive barrier shall lap over the attachment flange of the weep screed so that incidental water drains to the exterior.
+
+### The weep screed shall not be buried, sealed, or blocked by landscaping, paving, or subsequent finishes.
+
+```datasheet
+label: Weep screed minimum clearance above finished grade
+type: range
+unit: in
+min: 4
+max: 6
+step: 1
+default: 4
+```
+
+```datasheet
+label: Weep screed minimum clearance above paved surfaces
+type: range
+unit: in
+min: 2
+max: 4
+step: 1
+default: 2
+```
+
+## Control and expansion joints {toc}
+
+### Control joints relieve drying shrinkage and thermal movement; without them, panel cracking is not a defect but an inevitability. {note}
+
+### Control joints shall be located so that no individual stucco panel exceeds the maximum area permitted by the project specification, not exceeding 144 ft² for vertical surfaces.
+
+### The maximum distance between control joints in any direction shall not exceed 18 ft.
+
+### The ratio of length to width of any unjointed panel shall not exceed 2.5 to 1.
+
+### Control joints shall be provided at all changes in substrate, at floor lines in multistory framed construction, and at re-entrant corners of openings.
+
+### Control and expansion joint locations shall be shown on the drawings and shall not be left to field determination by the applicator. [[drawing: control joint layout plan]]
+
+```datasheet
+label: Maximum stucco panel area between control joints
+type: range
+unit: ft²
+min: 100
+max: 144
+step: 4
+default: 144
+```
+
+```datasheet
+label: Maximum spacing between control joints
+type: range
+unit: ft
+min: 10
+max: 18
+step: 1
+default: 18
+```
+
+### Expansion joints shall be provided where the stucco crosses a building expansion joint or a structural movement joint and shall be detailed to accommodate the design movement under [[sync/joint-sealants]].
+
+## Corner and casing beads {toc}
+
+### Corner beads reinforce and straighten outside corners; casing beads form a clean, sealable termination where stucco meets dissimilar materials. {note}
+
+### Corner beads shall be installed at all external corners to align the plaster and resist edge chipping.
+
+### Casing beads shall be installed where stucco terminates against windows, doors, dissimilar materials, and at the top of walls.
+
+### A sealant joint shall be provided between the casing bead and the adjacent material, with sealant type and joint design specified under [[sync/joint-sealants]].
+
+### Casing beads and their flashing integration at openings shall be detailed to direct water to the exterior. [[drawing: window head and jamb stucco termination detail]]
+
+# Installation {toc}
+
+## Application sequence and workmanship determine whether the coats bond and cure as a monolithic cladding. {note}
+
+### The scratch coat shall be applied with sufficient pressure to fully embed the lath and shall be raked or scored horizontally to provide a key for the brown coat.
+
+### The brown coat shall be applied to the full nominal thickness, rodded straight and true, and floated to a uniform open texture to receive the finish coat.
+
+### The finish coat shall be applied uniformly to the approved texture and color and shall be worked to match the accepted sample panel.
+
+### Plaster shall not be retempered after it has begun to set, and partially set material shall be discarded.
+
+## Application over different substrates requires substrate-specific preparation. {note}
+
+### Concrete and concrete masonry substrates shall be clean, free of form-release agents and laitance, and shall be dampened or treated with a bonding agent as required to develop bond.
+
+### Where mechanical bond to concrete or masonry cannot be assured, self-furred metal lath shall be installed and a three-coat system applied.
+
+### Soffit plaster shall be installed over metal lath with attachment and joint spacing as required by ASTM C1063 for horizontal and overhead surfaces.
+
+## Crack control and continuity at penetrations limit the entry points for water. {note}
+
+### Diagonal lath reinforcement shall be installed at the corners of openings to resist stress-concentration cracking.
+
+### Penetrations through the stucco shall be flashed and sealed so that water draining within the assembly is directed to the exterior and not into the wall cavity.
+
+# Delivery, Storage, and Handling {toc}
+
+## Cementitious materials lose performance when exposed to moisture or contamination before use. {note}
+
+### Cement, lime, and pre-blended products shall be delivered in unopened original packaging bearing the manufacturer's identification.
+
+### Cementitious materials shall be stored off the ground, under cover, and protected from moisture, and any material that has hydrated, lumped, or partially set shall be discarded.
+
+### Aggregate shall be stored to prevent contamination by soil, organic material, and other deleterious substances.
+
+### Accessories shall be stored to prevent bending, corrosion, and distortion of attachment flanges.
+
+# Warranty {toc}
+
+## The warranty allocates responsibility for early-life cracking and water intrusion to the installer and, where applicable, the system manufacturer. {note}
+
+### The Contractor shall warrant the stucco assembly against defects in materials and workmanship, including delamination, excessive cracking beyond shrinkage tolerances, and water intrusion attributable to the plastering work, for the period specified.
+
+### Where a proprietary one-coat or pre-blended system is used, the manufacturer's system warranty shall be provided in addition to the Contractor's warranty.
+
+```datasheet
+label: Contractor workmanship warranty period
+type: range
+unit: yr
+min: 1
+max: 5
+step: 1
+default: 2
+```
+
+```datasheet
+label: Manufacturer system warranty (proprietary systems)
+type: range
+unit: yr
+min: 5
+max: 15
+step: 5
+default: 10
+```
+
+# Maintenance and Spare Materials {toc}
+
+## Stucco repairs depend on matching the original color, texture, and source, so a small reserve of finish material and an accurate record prevent visible patches. {note}
+
+### The Contractor shall deliver a record of finish coat color, texture, and source for each elevation to support future repairs.
+
+### The Contractor shall deliver spare finish coat material of each color sufficient for incidental repair, stored in sealed, labeled containers.
+
+```datasheet
+label: Spare finish coat material delivered (per color)
+type: range
+unit: bag
+min: 1
+max: 4
+step: 1
+default: 2
+```
+
+# Copyright {toc}
+
+## This standard was independently authored from public consensus standards, building codes, and professional knowledge. {note}
+
+### This standard is licensed CC BY-SA and contains no proprietary guide-specification prose.