Exterior Painting and Coatings

Revision 3 · SynC Standards Team — Specifier, SynC (SynC Platform Team / Platform Standards) ✓ Official · Jun 4, 2026 +753 −557

Granular element model: citable clauses + {note} rationale
Showing changes from Rev 2 to Rev 3 in Exterior Painting and Coatings.
---
title: Exterior Painting and Coatings
category: Architectural / Finishes
toc_depth: 3
description: >
When to use: Field-applied protective and decorative coating systems on exterior building substrates in commercial, institutional, and multi-family residential construction. Covers surface preparation, priming, and finish coating of exposed exterior concrete, concrete masonry and stucco, structural and miscellaneous steel, galvanized and other non-ferrous metals, exterior wood, and previously-painted exterior surfaces. Includes acrylic latex, elastomeric, water-based and high-build epoxy, polyurethane, and alkyd coating systems applied to walls, soffits, fascia, exposed structure, railings, doors and frames, and exterior mechanical and electrical work scheduled to be field-painted.
Not intended for: Interior finishes (see [[sync/interior-painting]]); shop priming and shop finish coating of structural steel performed at the fabricator (see [[sync/structural-steel-framing]]); factory finishes on architectural metals, storefront, and curtain wall (see [[sync/aluminum-entrances-and-storefronts]]); below-grade waterproofing and dampproofing (see [[sync/below-grade-waterproofing]]); fluid-applied air and water-resistive barriers within the wall assembly; traffic-bearing deck coatings and parking structure coatings; roof coatings and roof membranes (see [[sync/membrane-roofing]]); intumescent fireproofing (see [[sync/fireproofing]]); concrete curing compounds and penetrating water repellents that leave no film; and pavement marking paints.
---
# Scope
This standard governs surface preparation, priming, and finish coating of exposed exterior architectural substrates in commercial and institutional construction. The work includes furnishing all materials, equipment, scaffolding, and labor required to deliver a uniform, durable, weather-resistant, and properly identified coating on exterior concrete, concrete masonry and cement plaster (stucco), structural and miscellaneous steel, galvanized and non-ferrous metal, exterior wood, and previously-painted exterior surfaces scheduled to be coated. Exterior coatings are the building's first line of defense against ultraviolet degradation, wind-driven rain, freeze-thaw cycling, and atmospheric corrosion; unlike interior paint, an exterior coating is a protective system whose failure exposes the substrate to deterioration, not merely a cosmetic blemish.
The Contractor shall treat the work as a coating system, not a sequence of coats. The substrate, the surface preparation grade, the primer, and the finish coats shall be selected and applied together so that the cured film bonds tenaciously to the substrate, achieves the specified dry film thickness, resists the service environment, and presents the specified sheen and color uniformly. A finish coat is only as good as the preparation and primer beneath it; the most common cause of premature exterior coating failure is inadequate surface preparation, not defective coating material. The second most common cause is application outside the manufacturer's environmental limits — coating applied to a damp, hot, or cold substrate, or applied when dew, rain, or frost arrives before the film has cured.
Coordinate substrate readiness with [[sync/cast-in-place-concrete]] and [[sync/unit-masonry]] for cure time and surface condition of cementitious substrates, with [[sync/structural-steel-framing]] for the boundary between shop-applied prime coats and field finish coats, with [[sync/sheet-metal-flashing-and-trim]] and [[sync/aluminum-entrances-and-storefronts]] for factory-finished metals that are not to be field-painted, and with [[sync/membrane-roofing]] for the termination of coatings at roof edges and parapets. Where coatings are applied over substrates governed by other standards, the surface preparation and finish requirements of this standard control unless the referenced standard imposes a more stringent requirement.
# Referenced Standards
All materials, surface preparation, and application shall comply with the latest edition adopted by the Authority Having Jurisdiction for each of the following standards. Where the contract documents or a referenced standard 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. The surface-preparation standards formerly published by SSPC and NACE are now maintained by AMPP (Association for Materials Protection and Performance); the original SSPC-SP and NACE numbers remain in active use and are retained here for clarity.
| Standard | Title |
|----------|-------|
| MPI Architectural Painting Specification Manual | Master Painters Institute — exterior (EXT) coating system numbers, product (MPI) numbers, and Approved Products List |
| MPI Gloss and Sheen Standards | Master Painters Institute — gloss levels G1 through G7 |
| ASTM D16 | Standard Terminology for Paint, Related Coatings, Materials, and Applications |
| SSPC-SP 1 | Solvent Cleaning |
| SSPC-SP 2 | Hand Tool Cleaning |
| SSPC-SP 3 | Power Tool Cleaning |
| SSPC-SP 6 / NACE No. 3 | Commercial Blast Cleaning |
| SSPC-SP 10 / NACE No. 2 | Near-White Metal Blast Cleaning |
| SSPC-SP 13 / NACE No. 6 | Surface Preparation of Concrete |
| SSPC-PA 2 | Procedure for Determining Conformance to Dry Coating Thickness Requirements |
| ASTM D4258 | Standard Practice for Surface Cleaning Concrete for Coating |
| ASTM D4259 | Standard Practice for Abrading Concrete |
| ASTM D4263 | Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet Method |
| ASTM D3359 | Standard Test Methods for Rating Adhesion by Tape Test |
| ASTM D6904 | Standard Practice for Resistance to Wind-Driven Rain for Exterior Coatings Applied on Masonry |
| ASTM D6237 | Standard Guide for Painting Inspectors (Concrete and Masonry Substrates) |
| SCAQMD Rule 1113 | Architectural Coatings (volatile organic compound content limits) |
| EPA 40 CFR 59, Subpart D | National Volatile Organic Compound Emission Standards for Architectural Coatings (AIM rule) |
The MPI Architectural Painting Specification Manual is the manufacturer-agnostic reference for exterior coating systems in North American commercial construction. MPI assigns a system number to each generic combination of substrate, primer, and finish (for example, the latex-over-alkali-resistant-primer systems for exterior concrete and masonry, and the high-performance systems for exterior steel), and assigns a product (MPI) number to each generic coating type with defined minimum performance. MPI product numbers and system numbers are an open reference standard and may be cited to define performance without naming any manufacturer. The MPI Approved Products List identifies which commercially available products meet each MPI product number, and selecting from it lets the specifier require a performance level without anchoring the specification to a single brand.
# Submittals
## Action Submittals
The Contractor shall submit the following for the Architect's review prior to procurement and application. Application of any coating system shall not begin until the corresponding submittals have been reviewed and returned, and until the field mock-up, where required, has been accepted.
**Product Data:** Manufacturer's technical data sheets for every coating product, identifying the generic resin type, the MPI product number where applicable, the recommended substrates, the wet and dry film thickness per coat, the recommended number of coats, the minimum and maximum recoat windows, the application temperature and humidity limits, and the VOC content in grams per liter.
**Coating System Schedule:** A schedule cross-referencing each scheduled exterior substrate and surface condition to the proposed primer and finish products, the MPI EXT system number, the number of coats, the total system dry film thickness, and the specified gloss level, organized by substrate type.
**Color Samples:** Manufacturer's standard color fan decks for initial color selection, followed by drawdown samples of each final selected color, formula, and gloss on a representative substrate for the Architect's approval before bulk material is ordered.
**Surface Preparation Plan:** A written description of the surface preparation method proposed for each substrate, referenced to the applicable SSPC-SP or ASTM standard, including dust control, containment, and disposal provisions where abrasive blasting or coating removal is required.
```datasheet
label: Action Submittals Required
type: checkbox
options:
- "Product data — all primers and finish coats"
- "Coating system schedule by substrate (MPI EXT system numbers)"
- "Manufacturer color fan decks and final drawdown samples"
- "Surface preparation plan referenced to SSPC-SP / ASTM grades"
- "Field mock-up identification and schedule"
- "Safety data sheets (SDS) for all products"
- "VOC content statements for VOC-regulated areas"
default: "Product data — all primers and finish coats"
```
## Closeout Submittals
- A final coating schedule recording the actual products, colors, formulas, gloss levels, and dry film thicknesses applied to each substrate, suitable for future maintenance and recoating
- Manufacturer warranty documentation for all coating products carrying a warranty
- Maintenance instructions describing recommended cleaning methods, touch-up procedures, and the recoat interval for each coating system
# Quality Assurance
## Applicator Qualifications
Exterior coating work shall be performed by an applicator who is experienced in commercial exterior painting of the substrate types and coating systems required on this project, and who is acceptable to the coating manufacturer for application of the specified high-performance systems. High-performance systems — elastomeric, epoxy, and polyurethane coatings — require controlled mixing ratios, induction times, pot-life management, and wet-film monitoring that general painting labor is frequently not trained to execute; the consequences of error are coating failure under weather exposure rather than a touch-up.
## Manufacturer's Approved Products
Each coating product shall meet the performance of the MPI product number assigned to its position in the coating system, and where the contract documents require MPI-listed products, each product shall appear on the current MPI Approved Products List for that MPI number. Specifying by MPI number lets the Contractor select from competing approved products while guaranteeing the minimum performance the system requires.
```datasheet
label: MPI Approved Products List Compliance Required
type: radio
options:
- "Yes — all products shall be MPI-listed for the assigned MPI product number"
- "No — products to meet performance described, MPI listing not mandatory"
default: "Yes — all products shall be MPI-listed for the assigned MPI product number"
```
## Single Manufacturer per System
All coats within a single coating system — primer, intermediate, and finish — shall be furnished by one manufacturer and shall be confirmed by that manufacturer as compatible for use together over the specified substrate and surface preparation. Mixing primers and finishes from different manufacturers transfers the risk of intercoat adhesion failure to the Contractor and voids the system warranty; the manufacturer will not warrant a film it did not formulate as a system.
```datasheet
label: Coating System Sourcing
type: radio
options:
- "Single manufacturer for primer through finish of each system"
- "Primer and finish from different manufacturers — manufacturer-confirmed compatibility required"
default: "Single manufacturer for primer through finish of each system"
```
## Field Mock-Up
Where the contract documents require a mock-up, the Contractor shall prepare and coat a representative area of each major substrate and coating system at a location directed by the Architect. The mock-up shall demonstrate the surface preparation, the primer, the full number of finish coats, the final color and gloss, the application method, and the achieved appearance under exterior daylight. The accepted mock-up establishes the minimum standard of appearance and workmanship for the production work and shall remain in place and protected for comparison until the work is accepted.
```datasheet
label: Field Mock-Up Required
type: radio
options:
- "Yes — one mock-up per major substrate and coating system"
- "No"
default: "Yes — one mock-up per major substrate and coating system"
```
```datasheet
label: Mock-Up Minimum Area per Substrate
type: range
unit: sq ft
options:
min: 50
max: 200
step: 25
default: 100
```
# Environmental and Service Conditions
## Service Environment Classification
The coating system shall be selected for the service environment to which the building is exposed, because the environment governs which generic resin will retain color, gloss, and film integrity over the design service life. Acrylic latex retains color and resists chalking far better than alkyd in ultraviolet exposure; epoxy resists chemical and abrasion exposure but chalks rapidly under ultraviolet and is therefore used as an intermediate or primer beneath a polyurethane topcoat in exterior steel systems; polyurethane provides the best combination of ultraviolet, abrasion, and chemical resistance for exposed metal.
```datasheet
label: Exterior Service Environment
type: select
drawing_ref: true
options:
- "Normal atmospheric — suburban or rural, low pollution"
- "Urban / industrial atmospheric — elevated pollutants and grime"
- "Coastal / marine — chloride-laden air within several miles of saltwater"
- "Chemical / process-adjacent — periodic exposure to chemical splash or fumes"
default: "Normal atmospheric — suburban or rural, low pollution"
```
## Temperature Limits During Application
Coatings shall not be applied when the ambient air temperature or the substrate surface temperature is below the minimum or above the maximum stated on the manufacturer's technical data sheet, and these limits shall be maintained throughout the application and the initial cure period. Most conventional waterborne coatings require a minimum of 50 °F (10 °C); some low-temperature-cure formulations are rated to 35 °F (2 °C). Below the minimum, waterborne films fail to coalesce — the polymer particles do not fuse into a continuous film — and the result is a weak, porous, prematurely failing coating that may appear acceptable when first applied. Above the maximum, solvent or water flashes off too rapidly, causing dry spray, lap marks, and poor wet edge.
```datasheet
label: Minimum Air and Surface Temperature During Application
type: range
unit: °F
options:
min: 35
max: 50
step: 5
default: 50
```
## Dew Point and Substrate Moisture
Coatings shall not be applied unless the substrate surface temperature is at least 5 °F (3 °C) above the measured dew point and the surface is dry, and application shall stop if conditions change such that condensation forms during application or before the film has cured. Coating applied to a surface at or below the dew point traps a film of condensed moisture between the coating and the substrate, which prevents adhesion and produces blistering, blushing, and delamination. The Contractor shall measure and record air temperature, relative humidity, surface temperature, and dew point at the start of each application period and at intervals during the work.
```datasheet
label: Minimum Surface Temperature Above Dew Point
type: range
unit: °F
options:
min: 5
max: 10
step: 1
default: 5
```
## Wind, Rain, and Drying Window
Coatings shall not be applied when rain, fog, frost, or condensation is present or imminent within the manufacturer's stated drying window for the coat being applied. Exterior coatings shall not be applied in wind conditions that cause dry spray, overspray drift, or contamination of the wet film by airborne dust and debris. The Contractor shall confirm the local weather forecast before beginning each day's exterior coating and shall not apply a coat that cannot achieve its minimum dry-to-rain time before the next precipitation event.
# Coating Systems by Substrate
## Concrete and Cementitious Substrates
Exterior cast-in-place concrete, precast concrete, cement plaster (stucco), and concrete masonry are alkaline, porous, and prone to efflorescence and alkali attack on coatings that are not formulated to resist it. The standard system for these substrates is an alkali-resistant primer followed by acrylic latex finish coats; where the wall must bridge hairline cracks and resist wind-driven rain, an elastomeric coating system is used instead. The coating selected shall match the MPI EXT system number for the substrate and the chosen performance.
```datasheet
label: Concrete / Masonry / Stucco Coating System
type: select
drawing_ref: true
options:
- "Acrylic latex over alkali-resistant primer (standard breathable decorative system)"
- "Elastomeric over masonry primer (crack-bridging, wind-driven-rain resistant)"
- "High-build acrylic over block filler (concrete masonry — fills and decorates)"
- "Water-based epoxy (high-traffic, washdown, or chemical-adjacent surfaces)"
default: "Acrylic latex over alkali-resistant primer (standard breathable decorative system)"
```
## Block Filler for Concrete Masonry
Exposed concrete masonry shall receive a block filler before the primer and finish coats unless the masonry has been factory-prefilled. Concrete masonry is deeply porous and open-celled; without a high-build block filler to bridge and fill the open texture, the finish coats sink into the surface, leave pinholes, and provide no continuous film for weather protection. Block filler shall be applied to fill the surface voids completely and provide a uniform base for the finish system.
```datasheet
label: Block Filler on Concrete Masonry
type: radio
options:
- "Required — high-build block filler before primer/finish"
- "Not required — masonry is factory-prefilled or substrate is not CMU"
drawing_ref: true
default: "Required — high-build block filler before primer/finish"
```
## Ferrous Metal — Structural and Miscellaneous Steel
Exposed ferrous metal scheduled to be field-painted shall receive a corrosion-inhibiting primer followed by finish coats appropriate to the service environment. The coating system for exposed steel in normal atmospheric exposure is typically an acrylic or alkyd direct-to-metal system over a rust-inhibiting primer; for corrosive, coastal, or high-durability exposure, a three-coat high-performance system of a zinc-rich or epoxy primer, an epoxy intermediate, and an aliphatic polyurethane finish is used. Where the steel was shop-primed under [[sync/structural-steel-framing]], the field system shall be compatible with the shop primer; incompatible field coats over an unknown shop primer is a frequent cause of lifting and delamination, and the Contractor shall confirm compatibility or apply a tie-coat before finishing.
```datasheet
label: Ferrous Metal Coating System
type: select
drawing_ref: true
options:
- "Acrylic DTM over rust-inhibiting primer (normal atmospheric, decorative)"
- "Alkyd enamel over rust-inhibiting primer (normal atmospheric, traditional)"
- "Epoxy primer / epoxy intermediate / polyurethane finish (corrosive, coastal, high-durability)"
- "Zinc-rich primer / epoxy / polyurethane (maximum corrosion protection)"
default: "Acrylic DTM over rust-inhibiting primer (normal atmospheric, decorative)"
```
## Galvanized and Non-Ferrous Metal
Galvanized steel, aluminum, and other non-ferrous metals scheduled to be field-painted shall receive a primer specifically formulated for the metal, applied after solvent cleaning and any required passivation or etch. New galvanized surfaces carry residual rolling oils and a passivating treatment that cause ordinary primers to peel; a galvanized-compatible bonding primer (or an acrylic direct-to-metal product listed for galvanized) is required. Oil-based and alkyd primers shall not be applied directly to galvanized steel, because the zinc surface saponifies the alkyd binder and the coating fails by peeling.
```datasheet
label: Galvanized / Non-Ferrous Metal Primer
type: radio
options:
- "Waterborne bonding primer formulated for galvanized / non-ferrous"
- "Acrylic direct-to-metal listed for galvanized"
- "Not applicable — no galvanized or non-ferrous metal scheduled"
drawing_ref: true
default: "Waterborne bonding primer formulated for galvanized / non-ferrous"
```
## Exterior Wood
Exterior wood scheduled to be coated shall receive a primer suited to the finish — an alkali-resistant, stain-blocking primer for opaque (paint) finishes, or a penetrating finish for transparent and semi-transparent finishes — followed by the specified topcoats. Knots and resinous areas shall receive a stain-blocking spot primer to prevent bleed-through. Exterior wood expands and contracts with moisture, so finish coats shall remain flexible; a brittle, high-gloss film over dimensionally active wood cracks and peels.
```datasheet
label: Exterior Wood Finish Type
type: select
drawing_ref: true
options:
- "Opaque (paint) — acrylic latex over stain-blocking exterior primer"
- "Semi-transparent stain — penetrating, lets grain show"
- "Transparent / clear — film-forming exterior varnish or clear sealer"
- "Not applicable — no exterior wood scheduled to be coated"
default: "Opaque (paint) — acrylic latex over stain-blocking exterior primer"
```
## Previously-Painted Surfaces
Previously-painted exterior surfaces scheduled for recoating shall be assessed for the soundness and the adhesion of the existing coating before recoating. All loose, peeling, blistered, and chalking coating shall be removed; the remaining sound coating shall be cleaned and dulled to provide a mechanical key; and the compatibility of the new coating with the existing aged film shall be confirmed by a test patch and adhesion test where the existing coating type is unknown. Recoating over a failing or incompatible existing film simply transfers the failure to the new coating.
```datasheet
label: Existing Coating Treatment
type: select
drawing_ref: true
options:
- "Spot-repair — remove failed areas, clean and dull sound coating, recoat"
- "Full removal to substrate — existing coating unsound or incompatible"
- "Not applicable — new substrate"
default: "Spot-repair — remove failed areas, clean and dull sound coating, recoat"
```
# Surface Preparation by Substrate
## General Surface Preparation Requirements
Surface preparation is the single most important determinant of exterior coating performance and shall be completed and accepted before any primer is applied. All surfaces shall be clean, dry, and free of dirt, dust, oil, grease, form-release agents, efflorescence, laitance, loose or failing coating, rust, mill scale, mildew, and any other contaminant that would impair adhesion. The preparation grade for each substrate shall be as specified below and shall conform to the cited SSPC-SP or ASTM standard.
## Solvent Cleaning of All Metals
All ferrous, galvanized, and non-ferrous metal shall be solvent cleaned in accordance with SSPC-SP 1 to remove oil, grease, and soluble contaminants before any further preparation. SSPC-SP 1 is a prerequisite for every other metal-preparation grade; abrasive or mechanical cleaning performed over oil or grease merely drives the contaminant into the surface profile and guarantees adhesion failure regardless of the cleanliness achieved afterward.
## Ferrous Metal Preparation Grade
The preparation grade for exposed ferrous metal shall be selected to match the coating system and the service environment. Hand-tool cleaning (SSPC-SP 2) and power-tool cleaning (SSPC-SP 3) remove loose rust, loose mill scale, and loose coating and are appropriate for touch-up and for mild environments under tolerant coatings; commercial blast cleaning (SSPC-SP 6 / NACE No. 3) and near-white blast cleaning (SSPC-SP 10 / NACE No. 2) remove essentially all mill scale and rust and establish the surface profile that high-performance epoxy and zinc-rich systems require for adhesion. High-performance systems applied over hand- or power-tool preparation will fail; the preparation grade is part of the coating system, not an independent choice.
```datasheet
label: Ferrous Metal Surface Preparation Grade
type: select
drawing_ref: true
options:
- "SSPC-SP 2 — Hand Tool Cleaning (touch-up, mild exposure)"
- "SSPC-SP 3 — Power Tool Cleaning (light rust, tolerant coatings)"
- "SSPC-SP 6 / NACE No. 3 — Commercial Blast (standard for epoxy systems)"
- "SSPC-SP 10 / NACE No. 2 — Near-White Blast (coastal, immersion-adjacent, zinc-rich)"
default: "SSPC-SP 3 — Power Tool Cleaning (light rust, tolerant coatings)"
```
## Concrete and Masonry Preparation
Concrete, masonry, and stucco shall be prepared in accordance with SSPC-SP 13 / NACE No. 6 and cleaned in accordance with ASTM D4258, removing laitance, form-release agents, efflorescence, curing compounds, dust, and any unsound material. Where the surface profile is too smooth or too contaminated to clean adequately, the surface shall be abraded in accordance with ASTM D4259 to expose a sound, slightly textured surface that the coating can key into. Efflorescence shall be removed and its source addressed; coating applied over efflorescence is pushed off the wall as the salts continue to migrate and crystallize beneath the film.
```datasheet
label: Concrete / Masonry Surface Preparation Method
type: select
drawing_ref: true
options:
- "Clean only per ASTM D4258 (sound, slightly porous surface)"
- "Clean and abrade per ASTM D4259 (smooth or contaminated surface)"
- "Mechanical / abrasive prep per SSPC-SP 13 (heavy contamination, recoat over failed coating)"
default: "Clean only per ASTM D4258 (sound, slightly porous surface)"
```
## Concrete Cure Before Coating
New concrete and masonry shall be allowed to cure before coating so that excess moisture and surface alkalinity have subsided to levels the coating can tolerate. A minimum cure of 28 days is the conventional requirement for film-forming coatings on new concrete unless the coating manufacturer's technical data sheet and a moisture test establish that a shorter interval is acceptable. Coating applied to green, high-moisture, high-alkalinity concrete blisters, delaminates, and suffers alkali attack on the binder.
```datasheet
label: Minimum Concrete Cure Before Coating
type: range
unit: days
options:
min: 14
max: 28
step: 7
default: 28
```
## Galvanized and Non-Ferrous Preparation
After SSPC-SP 1 solvent cleaning, galvanized and non-ferrous metals shall be prepared as required by the bonding primer manufacturer — typically a light abrasion or a chemical etch to remove the passivating layer and rolling oils and to provide a mechanical key. Weathered galvanized surfaces that have lost their passivation through outdoor exposure may require only solvent cleaning, while new, bright galvanized surfaces almost always require additional treatment for the primer to bond.
## Mildew Removal
Surfaces showing mildew shall be cleaned to remove all mildew before coating, because mildew continues to grow beneath a new coating and lifts it from the surface. Mildew shall be killed and removed by washing, and the dead mildew and its staining shall be removed from the surface before priming. Coating over live mildew is a recurring exterior failure in shaded, humid, and north-facing locations.
```datasheet
label: Mildewcide Additive in Finish Coats
type: radio
options:
- "Required — mildewcide added to finish coats (shaded, humid, or mildew-prone exposure)"
- "Not required — manufacturer's standard formulation"
drawing_ref: true
default: "Required — mildewcide added to finish coats (shaded, humid, or mildew-prone exposure)"
```
# Number of Coats and Dry Film Thickness
## Number of Coats
Each coating system shall consist of a primer plus the number of finish coats required to achieve the specified total dry film thickness, complete hide, and uniform appearance, and in no case fewer than one primer coat and two finish coats over previously uncoated substrates. The number of coats is a function of the substrate porosity, the color and hide of the finish, and the film build of the product; a deep or saturated color over a porous masonry substrate frequently requires an additional finish coat to achieve uniform hide and the specified film thickness.
```datasheet
label: Number of Finish Coats Over Primer
type: select
drawing_ref: true
options:
- "1 finish coat"
- "2 finish coats (standard)"
- "3 finish coats (deep colors, porous substrates, high-build systems)"
default: "2 finish coats (standard)"
```
## Total System Dry Film Thickness
The total system dry film thickness shall meet the minimum specified for the coating system and shall be verified in the field. Dry film thickness is the primary determinant of the protection and service life a coating delivers; a film applied too thin provides inadequate barrier protection and fails early, while a film applied too thick — particularly in a single coat — can mud-crack, sag, and cure improperly. The specified DFT shall fall within the manufacturer's recommended range for the product and the number of coats.
```datasheet
label: Minimum Total System Dry Film Thickness
type: range
unit: mils
options:
min: 3
max: 16
step: 1
default: 5
```
# Gloss and Sheen
## Gloss Level
The gloss level of the finish coat shall be as specified for each surface, expressed by the MPI gloss level designation (G1 through G7), which defines the gloss measured at 60 degrees and the sheen measured at 85 degrees. Gloss is both an appearance and a performance property: higher-gloss exterior finishes are generally harder, more washable, and more stain-resistant, but they telegraph surface imperfections and substrate texture more readily; lower-gloss finishes hide surface irregularities but soil more easily and are harder to clean. Flat and low-sheen finishes are common for large stucco and masonry wall fields where hiding texture matters; satin and semi-gloss are common for trim, metal, and doors where washability and a crisp appearance matter.
```datasheet
label: Finish Coat Gloss Level (MPI)
type: select
drawing_ref: true
options:
- "G1 — Matte / Flat (60° gloss max 5)"
- "G2 — Velvet (60° gloss max 10)"
- "G3 — Eggshell (60° gloss 10–25)"
- "G4 — Satin (60° gloss 20–35)"
- "G5 — Semi-Gloss (60° gloss 35–70)"
- "G6 — Gloss (60° gloss 70–85)"
- "G7 — High-Gloss (60° gloss above 85)"
default: "G4 — Satin (60° gloss 20–35)"
```
# Volatile Organic Compound Content
## VOC Compliance
All coatings shall comply with the VOC content limits in force at the project location. The applicable limits are the EPA national AIM rule (40 CFR 59, Subpart D) at minimum, and the more stringent state or regional limit where one applies — most notably SCAQMD Rule 1113 in Southern California, which is the strictest architectural-coating limit in the United States and is widely used as the de facto reference for low-VOC product lines nationwide. VOC limits are regional, and a coating that is compliant in one jurisdiction may be prohibited in another; the Contractor shall confirm the limits for the specific project location. Alkyd (oil-based) coatings carry inherently higher VOC content than waterborne acrylics and may be prohibited or restricted in low-VOC jurisdictions, which is one reason acrylic latex has displaced alkyd for most exterior architectural work.
```datasheet
label: VOC Limit Compliance Basis
type: select
drawing_ref: true
options:
- "EPA national AIM rule (40 CFR 59 Subpart D) — minimum"
- "SCAQMD Rule 1113 (strictest — Southern California and low-VOC reference)"
- "Other state / regional AQMD limit — confirm for project location"
default: "EPA national AIM rule (40 CFR 59 Subpart D) — minimum"
```
# Color
## Color Selection
The final color of each coating shall be [[drawing: as indicated on the exterior color schedule and finish plan]]. Custom and deep-tint colors shall be confirmed by an approved drawdown sample before bulk material is tinted and ordered, because deep and saturated exterior colors fade and chalk faster than standard colors, require more finish coats to achieve uniform hide, and may not be available in every coating product. Where a coating is supplied in a limited factory color range, the specified color shall be confirmed against the available range during submittal review.
```datasheet
label: Color Determination
type: radio
options:
- "Custom — per exterior color schedule, confirmed by approved drawdown"
- "Manufacturer standard color — selected from available range"
drawing_ref: true
default: "Custom — per exterior color schedule, confirmed by approved drawdown"
```
# Field Testing
## Dry Film Thickness Verification
The Contractor shall verify the dry film thickness of coatings applied to metal substrates in accordance with SSPC-PA 2, using a Type 1 (magnetic pull-off) or Type 2 (electronic) gauge, and shall record the spot and area measurements. SSPC-PA 2 establishes the statistically valid procedure for confirming that the applied film meets the specified thickness, including the spot-measurement and area-measurement averaging method and the acceptable tolerance band. DFT on non-ferrous and non-metallic substrates shall be verified by the manufacturer's recommended method, including wet-film gauge readings during application correlated to the target dry film thickness.
```datasheet
label: Dry Film Thickness Field Verification
type: radio
options:
- "Required on metal substrates per SSPC-PA 2"
- "Required on all substrates (metal per SSPC-PA 2; others per manufacturer method)"
default: "Required on metal substrates per SSPC-PA 2"
```
## Adhesion Testing
Where adhesion verification is specified, or where a coating is applied over an existing coating of unknown type, adhesion shall be verified by the tape test in accordance with ASTM D3359. The adhesion test confirms that the applied film and the substrate (or the existing film) have bonded adequately before the full work proceeds, and it is the standard means of qualifying a recoat over an unknown existing coating by means of a test patch.
```datasheet
label: Adhesion Testing (ASTM D3359)
type: radio
options:
- "Required — over existing coatings of unknown type and where specified"
- "Not required"
drawing_ref: true
default: "Required — over existing coatings of unknown type and where specified"
```
## Concrete Moisture Testing
Before coating concrete and masonry, the Contractor shall confirm acceptable surface moisture in accordance with ASTM D4263 (plastic sheet method), or by an electronic moisture meter or other method acceptable to the coating manufacturer. The ASTM D4263 plastic sheet method is a simple field screen in which a plastic sheet is taped to the surface and inspected for condensation after a set interval; condensation indicates capillary moisture migrating from within the concrete that will blister or delaminate the coating. Coating shall not be applied until the moisture condition is within the coating manufacturer's stated limit.
```datasheet
label: Concrete Moisture Test Before Coating
type: radio
options:
- "Required — ASTM D4263 plastic sheet method (or manufacturer-approved meter)"
- "Not required — substrate is not cementitious"
default: "Required — ASTM D4263 plastic sheet method (or manufacturer-approved meter)"
```
# Application
## Application Methods
Coatings shall be applied by brush, roller, or spray as appropriate to the product, the substrate, and the required appearance, and as permitted by the manufacturer's technical data sheet for the product. Spray application of exterior coatings shall be back-rolled or back-brushed where required to work the coating into porous substrates such as masonry and rough concrete; spray alone bridges the surface texture and leaves voids and pinholes that compromise weather resistance. The first coat into a porous substrate establishes the bond of the entire system and shall be worked into the surface, not merely laid over it.
```datasheet
label: Primary Application Method
type: select
options:
- "Brush and roller"
- "Spray, back-rolled into porous substrates"
- "Spray only (smooth substrates, non-porous metal)"
- "Per manufacturer's data sheet for each product"
default: "Per manufacturer's data sheet for each product"
```
## Recoat Times
Each coat shall be allowed to dry for the minimum recoat time stated on the manufacturer's technical data sheet before the next coat is applied, and shall be recoated within the maximum recoat window where the product specifies one. Recoating before the minimum time traps solvent or water and causes blistering and slow cure; recoating after the maximum window — common with epoxies — produces poor intercoat adhesion because the prior coat has cured too hard to bond, and the surface must then be abraded or tie-coated before recoating. The Contractor shall track the recoat windows for each coat, particularly for epoxy and polyurethane systems where the windows are narrow and exceeding them is a frequent cause of intercoat delamination.
## Film Continuity and Uniformity
The completed coating shall be a continuous film of uniform color, gloss, and thickness, free of runs, sags, drips, holidays, pinholes, dry spray, lap marks, brush marks, and foreign matter. The Contractor shall maintain a wet edge during application to avoid lap marks, and shall complete each continuous surface in one operation where possible so that no visible joint occurs in the field of a wall.
# Delivery, Storage, and Handling
Coatings shall be delivered to the project in the manufacturer's original sealed containers with labels and batch numbers intact and legible. Materials shall be stored in a clean, dry, secure location protected from freezing, from temperatures above the manufacturer's storage maximum, and from direct sunlight. Waterborne coatings are permanently ruined by freezing — the emulsion breaks and cannot be reconstituted — and shall be protected from freezing throughout storage and transport. Containers shall be kept closed except when material is being drawn, and partially used containers shall be resealed to prevent skinning and contamination. Material exceeding the manufacturer's shelf life shall not be used.
```datasheet
label: Coating Storage Temperature Range
type: range
unit: °F
options:
min: 40
max: 95
step: 5
setpoints: [40, 95]
default: 40
```
# Warranty
## Manufacturer's Warranty
Coating products shall be warranted by the manufacturer against defects in materials for the period stated in the manufacturer's published warranty. High-performance and elastomeric systems frequently carry extended film-integrity warranties contingent on application by an approved applicator and on documented compliance with the surface preparation and film thickness requirements; the Contractor shall comply with the manufacturer's conditions so that the Owner receives the full benefit of the warranty.
## Applicator's Warranty
The Contractor shall warrant the coating application against defective workmanship — including peeling, blistering, flaking, excessive chalking beyond the coating's published rate, and premature loss of adhesion attributable to inadequate surface preparation or improper application — for the project warranty period. Normal weathering, fading, and chalking within the coating's published performance, and damage from causes outside the Contractor's control, are not workmanship defects.
```datasheet
label: Applicator Workmanship Warranty Period
type: select
options:
- "1 year from substantial completion"
- "2 years from substantial completion"
- "5 years from substantial completion (high-performance systems)"
default: "2 years from substantial completion"
```
# Spare and Extra Materials
The Contractor shall deliver to the Owner sealed, labeled, original containers of each coating product, color, and gloss used on the project, for the Owner's use in future touch-up and maintenance. Each container shall be labeled with the product, the color name and formula, the gloss level, and the surfaces and locations where the material was used, so that the Owner can match and reorder without testing. Exterior touch-up is more difficult than interior because the in-place coating weathers and the touch-up must be blended; providing attic stock from the same production lot, and recording the color formula, minimizes future mismatch.
```datasheet
label: Extra Stock Quantity per Product / Color
type: range
unit: gallons
options:
min: 1
max: 5
step: 1
default: 1
```
+---
+title: Exterior Painting and Coatings
+category: Architectural / Finishes
+toc_depth: 3
+description: >
+ When to use: Field-applied protective and decorative coating systems on exterior building substrates in commercial, institutional, and multi-family residential construction. Covers surface preparation, priming, and finish coating of exposed exterior concrete, concrete masonry and stucco, structural and miscellaneous steel, galvanized and other non-ferrous metals, exterior wood, and previously-painted exterior surfaces. Includes acrylic latex, elastomeric, water-based and high-build epoxy, polyurethane, and alkyd coating systems applied to walls, soffits, fascia, exposed structure, railings, doors and frames, and exterior mechanical and electrical work scheduled to be field-painted.
+ Not intended for: Interior finishes (see [[sync/interior-painting]]); shop priming and shop finish coating of structural steel performed at the fabricator (see [[sync/structural-steel-framing]]); factory finishes on architectural metals, storefront, and curtain wall (see [[sync/aluminum-entrances-and-storefronts]]); below-grade waterproofing and dampproofing (see [[sync/below-grade-waterproofing]]); fluid-applied air and water-resistive barriers within the wall assembly; traffic-bearing deck coatings and parking structure coatings; roof coatings and roof membranes (see [[sync/membrane-roofing]]); intumescent fireproofing (see [[sync/fireproofing]]); concrete curing compounds and penetrating water repellents that leave no film; and pavement marking paints.
+---
+
+# Scope {toc}
+
+## This standard governs surface preparation, priming, and finish coating of exposed exterior architectural substrates in commercial and institutional construction. {note}
+
+## The work shall include furnishing all materials, equipment, scaffolding, and labor required to deliver a uniform, durable, weather-resistant, and properly identified coating on exterior concrete, concrete masonry and cement plaster (stucco), structural and miscellaneous steel, galvanized and non-ferrous metal, exterior wood, and previously-painted exterior surfaces scheduled to be coated.
+
+## Exterior coatings are the building's first line of defense against ultraviolet degradation, wind-driven rain, freeze-thaw cycling, and atmospheric corrosion; unlike interior paint, an exterior coating is a protective system whose failure exposes the substrate to deterioration, not merely a cosmetic blemish. {note}
+
+## The Contractor shall treat the work as a coating system, not a sequence of coats.
+
+## The substrate, the surface preparation grade, the primer, and the finish coats shall be selected and applied together so that the cured film bonds tenaciously to the substrate, achieves the specified dry film thickness, resists the service environment, and presents the specified sheen and color uniformly.
+
+## A finish coat is only as good as the preparation and primer beneath it; the most common cause of premature exterior coating failure is inadequate surface preparation, not defective coating material, and the second most common cause is application outside the manufacturer's environmental limits. {note}
+
+## The Contractor shall coordinate substrate readiness with [[sync/cast-in-place-concrete]] and [[sync/unit-masonry]] for cure time and surface condition of cementitious substrates, with [[sync/structural-steel-framing]] for the boundary between shop-applied prime coats and field finish coats, with [[sync/sheet-metal-flashing-and-trim]] and [[sync/aluminum-entrances-and-storefronts]] for factory-finished metals that are not to be field-painted, and with [[sync/membrane-roofing]] for the termination of coatings at roof edges and parapets.
+
+## Where coatings are applied over substrates governed by other standards, the surface preparation and finish requirements of this standard control unless the referenced standard imposes a more stringent requirement.
+
+# Referenced Standards {toc}
+
+## All materials, surface preparation, and application shall comply with the latest edition adopted by the Authority Having Jurisdiction for each of the following standards.
+
+## Referenced Standards List {toc}
+
+| Standard | Title |
+|----------|-------|
+| MPI Architectural Painting Specification Manual | Master Painters Institute — exterior (EXT) coating system numbers, product (MPI) numbers, and Approved Products List |
+| MPI Gloss and Sheen Standards | Master Painters Institute — gloss levels G1 through G7 |
+| ASTM D16 | Standard Terminology for Paint, Related Coatings, Materials, and Applications |
+| SSPC-SP 1 | Solvent Cleaning |
+| SSPC-SP 2 | Hand Tool Cleaning |
+| SSPC-SP 3 | Power Tool Cleaning |
+| SSPC-SP 6 / NACE No. 3 | Commercial Blast Cleaning |
+| SSPC-SP 10 / NACE No. 2 | Near-White Metal Blast Cleaning |
+| SSPC-SP 13 / NACE No. 6 | Surface Preparation of Concrete |
+| SSPC-PA 2 | Procedure for Determining Conformance to Dry Coating Thickness Requirements |
+| ASTM D4258 | Standard Practice for Surface Cleaning Concrete for Coating |
+| ASTM D4259 | Standard Practice for Abrading Concrete |
+| ASTM D4263 | Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet Method |
+| ASTM D3359 | Standard Test Methods for Rating Adhesion by Tape Test |
+| ASTM D6904 | Standard Practice for Resistance to Wind-Driven Rain for Exterior Coatings Applied on Masonry |
+| ASTM D6237 | Standard Guide for Painting Inspectors (Concrete and Masonry Substrates) |
+| SCAQMD Rule 1113 | Architectural Coatings (volatile organic compound content limits) |
+| EPA 40 CFR 59, Subpart D | National Volatile Organic Compound Emission Standards for Architectural Coatings (AIM rule) |
+
+### The MPI Architectural Painting Specification Manual is the manufacturer-agnostic reference for exterior coating systems in North American commercial construction; MPI assigns a system number to each generic combination of substrate, primer, and finish, and assigns a product (MPI) number to each generic coating type with defined minimum performance. {note}
+
+### MPI product numbers and system numbers are an open reference standard and may be cited to define performance without naming any manufacturer; the MPI Approved Products List identifies which commercially available products meet each MPI product number, letting the specifier require a performance level without anchoring the specification to a single brand. {note}
+
+## Compliance Hierarchy {toc}
+
+### Where the contract documents or a referenced standard 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.
+
+### The surface-preparation standards formerly published by SSPC and NACE are now maintained by AMPP (Association for Materials Protection and Performance); the original SSPC-SP and NACE numbers remain in active use and are retained here for clarity. {note}
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following for the Architect's review prior to procurement and application:
+
+- Product data — manufacturer's technical data sheets for every coating product, identifying the generic resin type, the MPI product number where applicable, the recommended substrates, the wet and dry film thickness per coat, the recommended number of coats, the minimum and maximum recoat windows, the application temperature and humidity limits, and the VOC content in grams per liter
+- Coating system schedule — a schedule cross-referencing each scheduled exterior substrate and surface condition to the proposed primer and finish products, the MPI EXT system number, the number of coats, the total system dry film thickness, and the specified gloss level, organized by substrate type
+- Color samples — manufacturer's standard color fan decks for initial color selection, followed by drawdown samples of each final selected color, formula, and gloss on a representative substrate for the Architect's approval before bulk material is ordered
+- Surface preparation plan — a written description of the surface preparation method proposed for each substrate, referenced to the applicable SSPC-SP or ASTM standard, including dust control, containment, and disposal provisions where abrasive blasting or coating removal is required
+
+```datasheet
+label: Action Submittals Required
+type: checkbox
+options:
+ - "Product data — all primers and finish coats"
+ - "Coating system schedule by substrate (MPI EXT system numbers)"
+ - "Manufacturer color fan decks and final drawdown samples"
+ - "Surface preparation plan referenced to SSPC-SP / ASTM grades"
+ - "Field mock-up identification and schedule"
+ - "Safety data sheets (SDS) for all products"
+ - "VOC content statements for VOC-regulated areas"
+default: "Product data — all primers and finish coats"
+```
+
+### Application of any coating system shall not begin until the corresponding submittals have been reviewed and returned, and until the field mock-up, where required, has been accepted.
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following at project closeout:
+
+- A final coating schedule recording the actual products, colors, formulas, gloss levels, and dry film thicknesses applied to each substrate, suitable for future maintenance and recoating
+- Manufacturer warranty documentation for all coating products carrying a warranty
+- Maintenance instructions describing recommended cleaning methods, touch-up procedures, and the recoat interval for each coating system
+
+```datasheet
+label: Required Closeout Submittals
+type: checkbox
+options:
+ - Final coating schedule of applied products, colors, formulas, gloss, and DFT
+ - Manufacturer warranty documentation
+ - Maintenance and recoat instructions
+default: [Final coating schedule of applied products, colors, formulas, gloss, and DFT, Manufacturer warranty documentation, Maintenance and recoat instructions]
+```
+
+# Quality Assurance {toc}
+
+## Applicator Qualifications {toc}
+
+### High-performance systems — elastomeric, epoxy, and polyurethane coatings — require controlled mixing ratios, induction times, pot-life management, and wet-film monitoring that general painting labor is frequently not trained to execute; the consequences of error are coating failure under weather exposure rather than a touch-up. {note}
+
+### Exterior coating work shall be performed by an applicator who is experienced in commercial exterior painting of the substrate types and coating systems required on this project.
+
+### The applicator shall be acceptable to the coating manufacturer for application of the specified high-performance systems.
+
+## Manufacturer's Approved Products {toc}
+
+### Specifying by MPI number lets the Contractor select from competing approved products while guaranteeing the minimum performance the system requires. {note}
+
+```datasheet
+label: MPI Approved Products List Compliance Required
+type: radio
+options:
+ - "Yes — all products shall be MPI-listed for the assigned MPI product number"
+ - "No — products to meet performance described, MPI listing not mandatory"
+default: "Yes — all products shall be MPI-listed for the assigned MPI product number"
+```
+
+### Each coating product shall meet the performance of the MPI product number assigned to its position in the coating system.
+
+### Where the contract documents require MPI-listed products, each product shall appear on the current MPI Approved Products List for that MPI number.
+
+## Single Manufacturer per System {toc}
+
+### Mixing primers and finishes from different manufacturers transfers the risk of intercoat adhesion failure to the Contractor and voids the system warranty; the manufacturer will not warrant a film it did not formulate as a system. {note}
+
+```datasheet
+label: Coating System Sourcing
+type: radio
+options:
+ - "Single manufacturer for primer through finish of each system"
+ - "Primer and finish from different manufacturers — manufacturer-confirmed compatibility required"
+default: "Single manufacturer for primer through finish of each system"
+```
+
+### All coats within a single coating system — primer, intermediate, and finish — shall be furnished by one manufacturer.
+
+### All coats within a single coating system shall be confirmed by that manufacturer as compatible for use together over the specified substrate and surface preparation.
+
+## Field Mock-Up {toc}
+
+```datasheet
+label: Field Mock-Up Required
+type: radio
+options:
+ - "Yes — one mock-up per major substrate and coating system"
+ - "No"
+default: "Yes — one mock-up per major substrate and coating system"
+```
+
+```datasheet
+label: Mock-Up Minimum Area per Substrate
+type: range
+unit: sq ft
+options:
+ min: 50
+ max: 200
+ step: 25
+default: 100
+```
+
+### Where the contract documents require a mock-up, the Contractor shall prepare and coat a representative area of each major substrate and coating system at a location directed by the Architect.
+
+### The mock-up shall demonstrate the surface preparation, the primer, the full number of finish coats, the final color and gloss, the application method, and the achieved appearance under exterior daylight.
+
+### The accepted mock-up establishes the minimum standard of appearance and workmanship for the production work and shall remain in place and protected for comparison until the work is accepted.
+
+# Environmental and Service Conditions {toc}
+
+## Service Environment Classification {toc}
+
+### Acrylic latex retains color and resists chalking far better than alkyd in ultraviolet exposure; epoxy resists chemical and abrasion exposure but chalks rapidly under ultraviolet and is therefore used as an intermediate or primer beneath a polyurethane topcoat in exterior steel systems; polyurethane provides the best combination of ultraviolet, abrasion, and chemical resistance for exposed metal. {note}
+
+```datasheet
+label: Exterior Service Environment
+type: select
+drawing_ref: true
+options:
+ - "Normal atmospheric — suburban or rural, low pollution"
+ - "Urban / industrial atmospheric — elevated pollutants and grime"
+ - "Coastal / marine — chloride-laden air within several miles of saltwater"
+ - "Chemical / process-adjacent — periodic exposure to chemical splash or fumes"
+default: "Normal atmospheric — suburban or rural, low pollution"
+```
+
+### The coating system shall be selected for the service environment to which the building is exposed, because the environment governs which generic resin will retain color, gloss, and film integrity over the design service life.
+
+## Temperature Limits During Application {toc}
+
+### Most conventional waterborne coatings require a minimum of 50 °F (10 °C); some low-temperature-cure formulations are rated to 35 °F (2 °C). {note}
+### Below the minimum, waterborne films fail to coalesce — the polymer particles do not fuse into a continuous film — and the result is a weak, porous, prematurely failing coating that may appear acceptable when first applied.
+### Above the maximum, solvent or water flashes off too rapidly, causing dry spray, lap marks, and poor wet edge. {note}
+
+```datasheet
+label: Minimum Air and Surface Temperature During Application
+type: range
+unit: °F
+options:
+ min: 35
+ max: 50
+ step: 5
+default: 50
+```
+
+### Coatings shall not be applied when the ambient air temperature or the substrate surface temperature is below the minimum or above the maximum stated on the manufacturer's technical data sheet.
+
+### These temperature limits shall be maintained throughout the application and the initial cure period.
+
+## Dew Point and Substrate Moisture {toc}
+
+### Coating applied to a surface at or below the dew point traps a film of condensed moisture between the coating and the substrate, which prevents adhesion and produces blistering, blushing, and delamination. {note}
+
+```datasheet
+label: Minimum Surface Temperature Above Dew Point
+type: range
+unit: °F
+options:
+ min: 5
+ max: 10
+ step: 1
+default: 5
+```
+
+### Coatings shall not be applied unless the substrate surface temperature is at least 5 °F (3 °C) above the measured dew point and the surface is dry.
+
+### Application shall stop if conditions change such that condensation forms during application or before the film has cured.
+
+### The Contractor shall measure and record air temperature, relative humidity, surface temperature, and dew point at the start of each application period and at intervals during the work.
+
+## Wind, Rain, and Drying Window {toc}
+
+### Coatings shall not be applied when rain, fog, frost, or condensation is present or imminent within the manufacturer's stated drying window for the coat being applied.
+
+### Exterior coatings shall not be applied in wind conditions that cause dry spray, overspray drift, or contamination of the wet film by airborne dust and debris.
+
+### The Contractor shall confirm the local weather forecast before beginning each day's exterior coating.
+
+### The Contractor shall not apply a coat that cannot achieve its minimum dry-to-rain time before the next precipitation event.
+
+# Coating Systems by Substrate {toc}
+
+## Concrete and Cementitious Substrates {toc}
+
+### Exterior cast-in-place concrete, precast concrete, cement plaster (stucco), and concrete masonry are alkaline, porous, and prone to efflorescence and alkali attack on coatings that are not formulated to resist it. {note}
+### The standard system for these substrates is an alkali-resistant primer followed by acrylic latex finish coats; where the wall must bridge hairline cracks and resist wind-driven rain, an elastomeric coating system is used instead.
+
+```datasheet
+label: Concrete / Masonry / Stucco Coating System
+type: select
+drawing_ref: true
+options:
+ - "Acrylic latex over alkali-resistant primer (standard breathable decorative system)"
+ - "Elastomeric over masonry primer (crack-bridging, wind-driven-rain resistant)"
+ - "High-build acrylic over block filler (concrete masonry — fills and decorates)"
+ - "Water-based epoxy (high-traffic, washdown, or chemical-adjacent surfaces)"
+default: "Acrylic latex over alkali-resistant primer (standard breathable decorative system)"
+```
+
+### The coating selected for concrete and cementitious substrates shall match the MPI EXT system number for the substrate and the chosen performance.
+
+## Block Filler for Concrete Masonry {toc}
+
+### Concrete masonry is deeply porous and open-celled; without a high-build block filler to bridge and fill the open texture, the finish coats sink into the surface, leave pinholes, and provide no continuous film for weather protection. {note}
+
+```datasheet
+label: Block Filler on Concrete Masonry
+type: radio
+options:
+ - "Required — high-build block filler before primer/finish"
+ - "Not required — masonry is factory-prefilled or substrate is not CMU"
+drawing_ref: true
+default: "Required — high-build block filler before primer/finish"
+```
+
+### Exposed concrete masonry shall receive a block filler before the primer and finish coats unless the masonry has been factory-prefilled.
+
+### Block filler shall be applied to fill the surface voids completely and provide a uniform base for the finish system.
+
+## Ferrous Metal — Structural and Miscellaneous Steel {toc}
+
+### The coating system for exposed steel in normal atmospheric exposure is typically an acrylic or alkyd direct-to-metal system over a rust-inhibiting primer; for corrosive, coastal, or high-durability exposure, a three-coat high-performance system of a zinc-rich or epoxy primer, an epoxy intermediate, and an aliphatic polyurethane finish is used. {note}
+### Incompatible field coats over an unknown shop primer is a frequent cause of lifting and delamination. {note}
+
+```datasheet
+label: Ferrous Metal Coating System
+type: select
+drawing_ref: true
+options:
+ - "Acrylic DTM over rust-inhibiting primer (normal atmospheric, decorative)"
+ - "Alkyd enamel over rust-inhibiting primer (normal atmospheric, traditional)"
+ - "Epoxy primer / epoxy intermediate / polyurethane finish (corrosive, coastal, high-durability)"
+ - "Zinc-rich primer / epoxy / polyurethane (maximum corrosion protection)"
+default: "Acrylic DTM over rust-inhibiting primer (normal atmospheric, decorative)"
+```
+
+### Exposed ferrous metal scheduled to be field-painted shall receive a corrosion-inhibiting primer followed by finish coats appropriate to the service environment.
+
+### Where the steel was shop-primed under [[sync/structural-steel-framing]], the field system shall be compatible with the shop primer, and the Contractor shall confirm compatibility or apply a tie-coat before finishing.
+
+## Galvanized and Non-Ferrous Metal {toc}
+
+### New galvanized surfaces carry residual rolling oils and a passivating treatment that cause ordinary primers to peel; a galvanized-compatible bonding primer (or an acrylic direct-to-metal product listed for galvanized) is required. {note}
+
+```datasheet
+label: Galvanized / Non-Ferrous Metal Primer
+type: radio
+options:
+ - "Waterborne bonding primer formulated for galvanized / non-ferrous"
+ - "Acrylic direct-to-metal listed for galvanized"
+ - "Not applicable — no galvanized or non-ferrous metal scheduled"
+drawing_ref: true
+default: "Waterborne bonding primer formulated for galvanized / non-ferrous"
+```
+
+### Galvanized steel, aluminum, and other non-ferrous metals scheduled to be field-painted shall receive a primer specifically formulated for the metal, applied after solvent cleaning and any required passivation or etch.
+
+### Oil-based and alkyd primers shall not be applied directly to galvanized steel, because the zinc surface saponifies the alkyd binder and the coating fails by peeling.
+
+## Exterior Wood {toc}
+
+### Exterior wood expands and contracts with moisture; a brittle, high-gloss film over dimensionally active wood cracks and peels. {note}
+
+```datasheet
+label: Exterior Wood Finish Type
+type: select
+drawing_ref: true
+options:
+ - "Opaque (paint) — acrylic latex over stain-blocking exterior primer"
+ - "Semi-transparent stain — penetrating, lets grain show"
+ - "Transparent / clear — film-forming exterior varnish or clear sealer"
+ - "Not applicable — no exterior wood scheduled to be coated"
+default: "Opaque (paint) — acrylic latex over stain-blocking exterior primer"
+```
+
+### Exterior wood scheduled to be coated shall receive a primer suited to the finish — an alkali-resistant, stain-blocking primer for opaque (paint) finishes, or a penetrating finish for transparent and semi-transparent finishes — followed by the specified topcoats.
+
+### Knots and resinous areas shall receive a stain-blocking spot primer to prevent bleed-through.
+
+### Finish coats on exterior wood shall remain flexible.
+
+## Previously-Painted Surfaces {toc}
+
+### Recoating over a failing or incompatible existing film simply transfers the failure to the new coating. {note}
+
+```datasheet
+label: Existing Coating Treatment
+type: select
+drawing_ref: true
+options:
+ - "Spot-repair — remove failed areas, clean and dull sound coating, recoat"
+ - "Full removal to substrate — existing coating unsound or incompatible"
+ - "Not applicable — new substrate"
+default: "Spot-repair — remove failed areas, clean and dull sound coating, recoat"
+```
+
+### Previously-painted exterior surfaces scheduled for recoating shall be assessed for the soundness and the adhesion of the existing coating before recoating.
+
+### All loose, peeling, blistered, and chalking coating shall be removed.
+
+### The remaining sound coating shall be cleaned and dulled to provide a mechanical key.
+
+### The compatibility of the new coating with the existing aged film shall be confirmed by a test patch and adhesion test where the existing coating type is unknown.
+
+# Surface Preparation by Substrate {toc}
+
+## General Surface Preparation Requirements {toc}
+
+### Surface preparation is the single most important determinant of exterior coating performance. {note}
+
+### Surface preparation shall be completed and accepted before any primer is applied.
+
+### All surfaces shall be clean, dry, and free of dirt, dust, oil, grease, form-release agents, efflorescence, laitance, loose or failing coating, rust, mill scale, mildew, and any other contaminant that would impair adhesion.
+
+### The preparation grade for each substrate shall be as specified below and shall conform to the cited SSPC-SP or ASTM standard.
+
+## Solvent Cleaning of All Metals {toc}
+
+### SSPC-SP 1 is a prerequisite for every other metal-preparation grade; abrasive or mechanical cleaning performed over oil or grease merely drives the contaminant into the surface profile and guarantees adhesion failure regardless of the cleanliness achieved afterward. {note}
+
+### All ferrous, galvanized, and non-ferrous metal shall be solvent cleaned in accordance with SSPC-SP 1 to remove oil, grease, and soluble contaminants before any further preparation.
+
+## Ferrous Metal Preparation Grade {toc}
+
+### Hand-tool cleaning (SSPC-SP 2) and power-tool cleaning (SSPC-SP 3) remove loose rust, loose mill scale, and loose coating and are appropriate for touch-up and for mild environments under tolerant coatings; commercial blast cleaning (SSPC-SP 6 / NACE No. 3) and near-white blast cleaning (SSPC-SP 10 / NACE No. 2) remove essentially all mill scale and rust and establish the surface profile that high-performance epoxy and zinc-rich systems require for adhesion. {note}
+### High-performance systems applied over hand- or power-tool preparation will fail; the preparation grade is part of the coating system, not an independent choice. {note}
+
+```datasheet
+label: Ferrous Metal Surface Preparation Grade
+type: select
+drawing_ref: true
+options:
+ - "SSPC-SP 2 — Hand Tool Cleaning (touch-up, mild exposure)"
+ - "SSPC-SP 3 — Power Tool Cleaning (light rust, tolerant coatings)"
+ - "SSPC-SP 6 / NACE No. 3 — Commercial Blast (standard for epoxy systems)"
+ - "SSPC-SP 10 / NACE No. 2 — Near-White Blast (coastal, immersion-adjacent, zinc-rich)"
+default: "SSPC-SP 3 — Power Tool Cleaning (light rust, tolerant coatings)"
+```
+
+### The preparation grade for exposed ferrous metal shall be selected to match the coating system and the service environment.
+
+## Concrete and Masonry Preparation {toc}
+
+### Coating applied over efflorescence is pushed off the wall as the salts continue to migrate and crystallize beneath the film. {note}
+
+```datasheet
+label: Concrete / Masonry Surface Preparation Method
+type: select
+drawing_ref: true
+options:
+ - "Clean only per ASTM D4258 (sound, slightly porous surface)"
+ - "Clean and abrade per ASTM D4259 (smooth or contaminated surface)"
+ - "Mechanical / abrasive prep per SSPC-SP 13 (heavy contamination, recoat over failed coating)"
+default: "Clean only per ASTM D4258 (sound, slightly porous surface)"
+```
+
+### Concrete, masonry, and stucco shall be prepared in accordance with SSPC-SP 13 / NACE No. 6 and cleaned in accordance with ASTM D4258, removing laitance, form-release agents, efflorescence, curing compounds, dust, and any unsound material.
+
+### Where the surface profile is too smooth or too contaminated to clean adequately, the surface shall be abraded in accordance with ASTM D4259 to expose a sound, slightly textured surface that the coating can key into.
+
+### Efflorescence shall be removed and its source addressed.
+
+## Concrete Cure Before Coating {toc}
+
+### Coating applied to green, high-moisture, high-alkalinity concrete blisters, delaminates, and suffers alkali attack on the binder. {note}
+
+```datasheet
+label: Minimum Concrete Cure Before Coating
+type: range
+unit: days
+options:
+ min: 14
+ max: 28
+ step: 7
+default: 28
+```
+
+### New concrete and masonry shall be allowed to cure before coating so that excess moisture and surface alkalinity have subsided to levels the coating can tolerate.
+
+### A minimum cure of 28 days is the conventional requirement for film-forming coatings on new concrete unless the coating manufacturer's technical data sheet and a moisture test establish that a shorter interval is acceptable.
+
+## Galvanized and Non-Ferrous Preparation {toc}
+
+### Weathered galvanized surfaces that have lost their passivation through outdoor exposure may require only solvent cleaning, while new, bright galvanized surfaces almost always require additional treatment for the primer to bond.
+
+### After SSPC-SP 1 solvent cleaning, galvanized and non-ferrous metals shall be prepared as required by the bonding primer manufacturer — typically a light abrasion or a chemical etch to remove the passivating layer and rolling oils and to provide a mechanical key.
+
+## Mildew Removal {toc}
+
+### Coating over live mildew is a recurring exterior failure in shaded, humid, and north-facing locations. {note}
+
+```datasheet
+label: Mildewcide Additive in Finish Coats
+type: radio
+options:
+ - "Required — mildewcide added to finish coats (shaded, humid, or mildew-prone exposure)"
+ - "Not required — manufacturer's standard formulation"
+drawing_ref: true
+default: "Required — mildewcide added to finish coats (shaded, humid, or mildew-prone exposure)"
+```
+
+### Surfaces showing mildew shall be cleaned to remove all mildew before coating, because mildew continues to grow beneath a new coating and lifts it from the surface.
+
+### Mildew shall be killed and removed by washing, and the dead mildew and its staining shall be removed from the surface before priming.
+
+# Number of Coats and Dry Film Thickness {toc}
+
+## Number of Coats {toc}
+
+### The number of coats is a function of the substrate porosity, the color and hide of the finish, and the film build of the product; a deep or saturated color over a porous masonry substrate frequently requires an additional finish coat to achieve uniform hide and the specified film thickness. {note}
+
+```datasheet
+label: Number of Finish Coats Over Primer
+type: select
+drawing_ref: true
+options:
+ - "1 finish coat"
+ - "2 finish coats (standard)"
+ - "3 finish coats (deep colors, porous substrates, high-build systems)"
+default: "2 finish coats (standard)"
+```
+
+### Each coating system shall consist of a primer plus the number of finish coats required to achieve the specified total dry film thickness, complete hide, and uniform appearance.
+
+### In no case shall a coating system over a previously uncoated substrate consist of fewer than one primer coat and two finish coats.
+
+## Total System Dry Film Thickness {toc}
+
+### Dry film thickness is the primary determinant of the protection and service life a coating delivers; a film applied too thin provides inadequate barrier protection and fails early, while a film applied too thick — particularly in a single coat — can mud-crack, sag, and cure improperly. {note}
+
+```datasheet
+label: Minimum Total System Dry Film Thickness
+type: range
+unit: mils
+options:
+ min: 3
+ max: 16
+ step: 1
+default: 5
+```
+
+### The total system dry film thickness shall meet the minimum specified for the coating system and shall be verified in the field.
+
+### The specified dry film thickness shall fall within the manufacturer's recommended range for the product and the number of coats.
+
+# Gloss and Sheen {toc}
+
+## Gloss Level {toc}
+
+### Gloss is both an appearance and a performance property: higher-gloss exterior finishes are generally harder, more washable, and more stain-resistant, but they telegraph surface imperfections and substrate texture more readily; lower-gloss finishes hide surface irregularities but soil more easily and are harder to clean. {note}
+### Flat and low-sheen finishes are common for large stucco and masonry wall fields where hiding texture matters; satin and semi-gloss are common for trim, metal, and doors where washability and a crisp appearance matter. {note}
+
+```datasheet
+label: Finish Coat Gloss Level (MPI)
+type: select
+drawing_ref: true
+options:
+ - "G1 — Matte / Flat (60° gloss max 5)"
+ - "G2 — Velvet (60° gloss max 10)"
+ - "G3 — Eggshell (60° gloss 10–25)"
+ - "G4 — Satin (60° gloss 20–35)"
+ - "G5 — Semi-Gloss (60° gloss 35–70)"
+ - "G6 — Gloss (60° gloss 70–85)"
+ - "G7 — High-Gloss (60° gloss above 85)"
+default: "G4 — Satin (60° gloss 20–35)"
+```
+
+### The gloss level of the finish coat shall be as specified for each surface, expressed by the MPI gloss level designation (G1 through G7), which defines the gloss measured at 60 degrees and the sheen measured at 85 degrees.
+
+# Volatile Organic Compound Content {toc}
+
+## VOC Compliance {toc}
+
+### SCAQMD Rule 1113 in Southern California is the strictest architectural-coating limit in the United States and is widely used as the de facto reference for low-VOC product lines nationwide; VOC limits are regional, and a coating that is compliant in one jurisdiction may be prohibited in another.
+### Alkyd (oil-based) coatings carry inherently higher VOC content than waterborne acrylics and may be prohibited or restricted in low-VOC jurisdictions, which is one reason acrylic latex has displaced alkyd for most exterior architectural work.
+
+```datasheet
+label: VOC Limit Compliance Basis
+type: select
+drawing_ref: true
+options:
+ - "EPA national AIM rule (40 CFR 59 Subpart D) — minimum"
+ - "SCAQMD Rule 1113 (strictest — Southern California and low-VOC reference)"
+ - "Other state / regional AQMD limit — confirm for project location"
+default: "EPA national AIM rule (40 CFR 59 Subpart D) — minimum"
+```
+
+### All coatings shall comply with the VOC content limits in force at the project location.
+
+### The applicable limits are the EPA national AIM rule (40 CFR 59, Subpart D) at minimum, and the more stringent state or regional limit where one applies.
+
+### The Contractor shall confirm the VOC limits for the specific project location.
+
+# Color {toc}
+
+## Color Selection {toc}
+
+### Deep and saturated exterior colors fade and chalk faster than standard colors, require more finish coats to achieve uniform hide, and may not be available in every coating product.
+
+```datasheet
+label: Color Determination
+type: radio
+options:
+ - "Custom — per exterior color schedule, confirmed by approved drawdown"
+ - "Manufacturer standard color — selected from available range"
+drawing_ref: true
+default: "Custom — per exterior color schedule, confirmed by approved drawdown"
+```
+
+### The final color of each coating shall be [[drawing: as indicated on the exterior color schedule and finish plan]].
+
+### Custom and deep-tint colors shall be confirmed by an approved drawdown sample before bulk material is tinted and ordered.
+
+### Where a coating is supplied in a limited factory color range, the specified color shall be confirmed against the available range during submittal review.
+
+# Field Testing {toc}
+
+## Dry Film Thickness Verification {toc}
+
+### SSPC-PA 2 establishes the statistically valid procedure for confirming that the applied film meets the specified thickness, including the spot-measurement and area-measurement averaging method and the acceptable tolerance band. {note}
+
+```datasheet
+label: Dry Film Thickness Field Verification
+type: radio
+options:
+ - "Required on metal substrates per SSPC-PA 2"
+ - "Required on all substrates (metal per SSPC-PA 2; others per manufacturer method)"
+default: "Required on metal substrates per SSPC-PA 2"
+```
+
+### The Contractor shall verify the dry film thickness of coatings applied to metal substrates in accordance with SSPC-PA 2, using a Type 1 (magnetic pull-off) or Type 2 (electronic) gauge, and shall record the spot and area measurements.
+
+### Dry film thickness on non-ferrous and non-metallic substrates shall be verified by the manufacturer's recommended method, including wet-film gauge readings during application correlated to the target dry film thickness.
+
+## Adhesion Testing {toc}
+
+### The adhesion test confirms that the applied film and the substrate (or the existing film) have bonded adequately before the full work proceeds, and it is the standard means of qualifying a recoat over an unknown existing coating by means of a test patch. {note}
+
+```datasheet
+label: Adhesion Testing (ASTM D3359)
+type: radio
+options:
+ - "Required — over existing coatings of unknown type and where specified"
+ - "Not required"
+drawing_ref: true
+default: "Required — over existing coatings of unknown type and where specified"
+```
+
+### Where adhesion verification is specified, or where a coating is applied over an existing coating of unknown type, adhesion shall be verified by the tape test in accordance with ASTM D3359.
+
+## Concrete Moisture Testing {toc}
+
+### The ASTM D4263 plastic sheet method is a simple field screen in which a plastic sheet is taped to the surface and inspected for condensation after a set interval; condensation indicates capillary moisture migrating from within the concrete that will blister or delaminate the coating. {note}
+
+```datasheet
+label: Concrete Moisture Test Before Coating
+type: radio
+options:
+ - "Required — ASTM D4263 plastic sheet method (or manufacturer-approved meter)"
+ - "Not required — substrate is not cementitious"
+default: "Required — ASTM D4263 plastic sheet method (or manufacturer-approved meter)"
+```
+
+### Before coating concrete and masonry, the Contractor shall confirm acceptable surface moisture in accordance with ASTM D4263 (plastic sheet method), or by an electronic moisture meter or other method acceptable to the coating manufacturer.
+
+### Coating shall not be applied until the moisture condition is within the coating manufacturer's stated limit.
+
+# Application {toc}
+
+## Application Methods {toc}
+
+### Spray alone bridges the surface texture and leaves voids and pinholes that compromise weather resistance. {note}
+
+```datasheet
+label: Primary Application Method
+type: select
+options:
+ - "Brush and roller"
+ - "Spray, back-rolled into porous substrates"
+ - "Spray only (smooth substrates, non-porous metal)"
+ - "Per manufacturer's data sheet for each product"
+default: "Per manufacturer's data sheet for each product"
+```
+
+### Coatings shall be applied by brush, roller, or spray as appropriate to the product, the substrate, and the required appearance, and as permitted by the manufacturer's technical data sheet for the product.
+
+### Spray application of exterior coatings shall be back-rolled or back-brushed where required to work the coating into porous substrates such as masonry and rough concrete.
+
+### The first coat into a porous substrate establishes the bond of the entire system and shall be worked into the surface, not merely laid over it.
+
+## Recoat Times {toc}
+
+### Recoating before the minimum time traps solvent or water and causes blistering and slow cure; recoating after the maximum window — common with epoxies — produces poor intercoat adhesion because the prior coat has cured too hard to bond, and the surface must then be abraded or tie-coated before recoating.
+
+### Each coat shall be allowed to dry for the minimum recoat time stated on the manufacturer's technical data sheet before the next coat is applied, and shall be recoated within the maximum recoat window where the product specifies one.
+
+### The Contractor shall track the recoat windows for each coat, particularly for epoxy and polyurethane systems where the windows are narrow and exceeding them is a frequent cause of intercoat delamination.
+
+## Film Continuity and Uniformity {toc}
+
+### The completed coating shall be a continuous film of uniform color, gloss, and thickness, free of runs, sags, drips, holidays, pinholes, dry spray, lap marks, brush marks, and foreign matter.
+
+### The Contractor shall maintain a wet edge during application to avoid lap marks.
+
+### The Contractor shall complete each continuous surface in one operation where possible so that no visible joint occurs in the field of a wall.
+
+# Delivery, Storage, and Handling {toc}
+
+## Waterborne coatings are permanently ruined by freezing — the emulsion breaks and cannot be reconstituted. {note}
+
+## Storage Temperature {toc}
+
+```datasheet
+label: Coating Storage Temperature Range
+type: range
+unit: °F
+options:
+ min: 40
+ max: 95
+ step: 5
+ setpoints: [40, 95]
+default: 40
+```
+
+### Coatings shall be delivered to the project in the manufacturer's original sealed containers with labels and batch numbers intact and legible.
+
+### Materials shall be stored in a clean, dry, secure location protected from freezing, from temperatures above the manufacturer's storage maximum, and from direct sunlight.
+
+### Waterborne coatings shall be protected from freezing throughout storage and transport.
+
+### Containers shall be kept closed except when material is being drawn, and partially used containers shall be resealed to prevent skinning and contamination.
+
+### Material exceeding the manufacturer's shelf life shall not be used.
+
+# Warranty {toc}
+
+## Manufacturer's Warranty {toc}
+
+### High-performance and elastomeric systems frequently carry extended film-integrity warranties contingent on application by an approved applicator and on documented compliance with the surface preparation and film thickness requirements. {note}
+
+### Coating products shall be warranted by the manufacturer against defects in materials for the period stated in the manufacturer's published warranty.
+
+### The Contractor shall comply with the manufacturer's conditions so that the Owner receives the full benefit of the warranty.
+
+## Applicator's Warranty {toc}
+
+### Normal weathering, fading, and chalking within the coating's published performance, and damage from causes outside the Contractor's control, are not workmanship defects. {note}
+
+```datasheet
+label: Applicator Workmanship Warranty Period
+type: select
+options:
+ - "1 year from substantial completion"
+ - "2 years from substantial completion"
+ - "5 years from substantial completion (high-performance systems)"
+default: "2 years from substantial completion"
+```
+
+### The Contractor shall warrant the coating application against defective workmanship — including peeling, blistering, flaking, excessive chalking beyond the coating's published rate, and premature loss of adhesion attributable to inadequate surface preparation or improper application — for the project warranty period.
+
+# Spare and Extra Materials {toc}
+
+## Exterior touch-up is more difficult than interior because the in-place coating weathers and the touch-up must be blended; providing attic stock from the same production lot, and recording the color formula, minimizes future mismatch.
+
+## Extra Stock Quantity {toc}
+
+```datasheet
+label: Extra Stock Quantity per Product / Color
+type: range
+unit: gallons
+options:
+ min: 1
+ max: 5
+ step: 1
+default: 1
+```
+
+### The Contractor shall deliver to the Owner sealed, labeled, original containers of each coating product, color, and gloss used on the project, for the Owner's use in future touch-up and maintenance.
+
+### Each container shall be labeled with the product, the color name and formula, the gloss level, and the surfaces and locations where the material was used, so that the Owner can match and reorder without testing.

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