Exterior Painting and Coatings

Revision 8 · Oct 8, 2026 +900 −755

SynC Standards Team — Specifier (Platform Standards) ✓ OfficialDiscloses employment SynC (SynC Platform Team)

Remade from scratch to the authoring rules: defaults asserted only where four of five projects would choose them, and scope boundaries matched to the neighboring standards

Showing changes from Rev 7 to Rev 8 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 {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}

−

−### 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.

−

−```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 {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}

−

−### All coats within a single coating system — primer, intermediate, and finish — shall be furnished by one manufacturer.

−

−```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 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}

−

−### 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.

−

−```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 {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}

−

−### 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.

−

−```datasheet

−label: Minimum Air and Surface Temperature During Application

−type: range

−unit: °F

−options:

− min: 35

− max: 50

− step: 5

−default: 50

−```

−

−### 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}

−

−### 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.

−

−```datasheet

−label: Minimum Surface Temperature Above Dew Point

−type: range

−unit: °F

−options:

− min: 5

− max: 10

− step: 1

−default: 5

−```

−

−### 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}

−

−### Exposed concrete masonry shall receive a block filler before the primer and finish coats unless the masonry has been factory-prefilled.

−

−```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"

−```

−

−### 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}

−

−### Exposed ferrous metal scheduled to be field-painted shall receive a corrosion-inhibiting primer followed by finish coats appropriate to the service environment.

−

−```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)"

−```

−

−### 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}

−

−### 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.

−

−```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"

−```

−

−### 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}

−

−### 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.

−

−```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"

−```

−

−### 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}

−

−### Previously-painted exterior surfaces scheduled for recoating shall be assessed for the soundness and the adhesion of the existing coating before recoating.

−

−```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"

−```

−

−### 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}

−

−### The preparation grade for exposed ferrous metal shall be selected to match the coating system and the service environment.

−

−```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 {toc}

−

−### Coating applied over efflorescence is pushed off the wall as the salts continue to migrate and crystallize beneath the film. {note}

−

−### 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.

−

−```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)"

−```

−

−### 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}

−

−### 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.

−

−```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 {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}

−

−### Whether a mildewcide additive is required in the finish coats shall be specified based on the substrate's exposure to shade, humidity, and mildew-prone conditions.

−

−```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}

−

−### 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.

−

−```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)"

−```

−

−### 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}

−

−### The total system dry film thickness shall meet the minimum specified for the coating system and shall be verified in the field.

−

−```datasheet

−label: Minimum Total System Dry Film Thickness

−type: range

−unit: mils

−options:

− min: 3

− max: 16

− step: 1

−default: 5

−```

−

−### 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}

−

−### 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.

−

−```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 {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:

− - "Manufacturer standard color — selected from available range"

−drawing_ref: "exterior color schedule"

−default: deferred

−```

−

−### 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}

−

−### 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.

−

−```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"

−```

−

−### 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}

−

−### 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.

−

−```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 {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}

−

−### 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.

−

−```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)"

−```

−

−### Coating shall not be applied until the moisture condition is within the coating manufacturer's stated limit.

−

−# Application Methods {toc}

−

−## Spray alone bridges the surface texture and leaves voids and pinholes that compromise weather resistance. {note}

−

−## 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.

−

−```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"

−```

−

−## 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}

−

−### 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.

−

−```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 {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.

+---

+title: Exterior Painting and Coatings

+category: Architectural / Finishes

+description: >

+ When to use: Field-applied decorative and protective coating systems on the exterior architectural substrates of commercial, institutional, and multi-family residential buildings: cast-in-place and precast concrete, concrete masonry, portland cement plaster (stucco), hollow metal doors and frames, miscellaneous metals and metal fabrications, exposed structural steel over its shop primer, galvanized steel including the factory-primed curtains and sections of coiling and sectional doors, aluminum and other non-ferrous metals, wood siding, trim, soffits, and doors, fiber-cement siding and trim, and previously painted exterior surfaces. Covers the finish and primer chemistry for each substrate (acrylic latex, elastomeric, high-build acrylic, waterborne acrylic-epoxy, mineral silicate, alkyd, waterborne acrylic-urethane, two-component aliphatic polyurethane, and the opaque, semi-transparent, and clear finishes for wood), surface preparation grades, substrate moisture and cure, application weather limits, sheen, number of coats and film thickness, color matching, volatile organic compound limits, mildew resistance, anti-graffiti coatings, mock-ups, field verification of thickness and adhesion, touch-up, warranty, and extra stock.

+ Not intended for: Interior painting (see [[sync/interior-painting]]); chemical-resistant, immersion, washdown, and industrial multi-coat systems and the linings and floor coatings of process areas (see [[sync/high-performance-coatings]]); shop priming, hot-dip galvanizing, and the coating systems a fabricator puts on steel in its shop (see [[sync/shop-painting-and-galvanizing]] and [[sync/structural-steel-framing]]); anodic, fluoropolymer, and coil finishes that aluminum and sheet metal receive at the factory (see [[sync/aluminum-entrances-and-storefronts]], [[sync/glazed-curtain-walls]], [[sync/metal-wall-panels]], and [[sync/sheet-metal-flashing-and-trim]]); wood and hollow metal doors coated at the factory (see [[sync/wood-doors]] and [[sync/exterior-doors-and-frames]]); the finish coat of exterior insulation and finish systems (see [[sync/exterior-insulation-and-finish-systems]]); roof coatings and liquid roof membranes (see [[sync/fluid-applied-roofing]]); traffic-bearing waterproofing membranes on plaza and parking decks (see [[sync/fluid-applied-waterproofing]]); below-grade waterproofing and dampproofing (see [[sync/below-grade-waterproofing]] and [[sync/dampproofing]]); air and water-resistive barrier membranes inside the wall assembly (see [[sync/air-barriers]]); intumescent and cementitious fireproofing (see [[sync/fireproofing]]); concrete curing compounds (see [[sync/concrete-curing-and-finishing]]); penetrating water repellents specified with the brick and architectural precast they protect (see [[sync/brick-masonry]] and [[sync/architectural-precast-concrete]]); pavement marking paints (see [[sync/pavement-markings]]); and the survey, removal, and disposal of lead-containing coatings (see [[sync/hazardous-material-abatement]]).

+---

+# Scope {toc}

+## This standard governs the surface preparation, priming, and finish coating of exterior architectural substrates in the field, where the coating is selected for weather resistance, color, and sheen rather than for chemical, immersion, or industrial washdown service. {note}

+## The furnished work shall comprise the surface preparation, primers, intermediate coats, finish coats, mildew treatment, touch-up, protection of adjacent work, and the field verification this standard requires, on every exterior surface [[drawing: the exterior elevations and the exterior finish schedule]] identify as field coated.

+## The substrates this standard coats are the following. {note}

+- Cast-in-place concrete, precast concrete scheduled for a field coating, and concrete masonry

+- Portland cement plaster (stucco) with a finish coat left unpigmented for coating under [[sync/plaster-and-stucco]]

+- Hollow metal doors and frames, miscellaneous metals, metal fabrications, and exposed structural steel delivered with a shop or factory primer

+- Galvanized steel, including the factory-primed curtains, hoods, and guides of coiling doors and the factory-primed sections of sectional doors, and aluminum and other non-ferrous metals scheduled for a field finish

+- Wood siding, trim, soffits, fascia, exterior millwork, and wood doors delivered unfinished, factory sealed, or factory primed for a field finish

+- Fiber-cement siding and trim

+- Previously painted exterior surfaces of any of these substrates

+## The boundary with [[sync/high-performance-coatings]] is the service, not the resin. A two-component polyurethane finish on a railing in a coastal town is architectural painting and is governed here; the same resin on a tank, a containment wall, or a surface washed down with chemicals is a high-performance system and is governed there. Where a surface sees chemical splash, immersion, or industrial washdown, the whole system for that surface is selected under that standard. {note}

+## The shop coat ends at the fabricator's door and the site work begins here. The shop coat on structural steel is governed by [[sync/structural-steel-framing]] and [[sync/shop-painting-and-galvanizing]], on miscellaneous metals by [[sync/miscellaneous-metals]], and on metal fabrications by [[sync/metal-fabrications]]; the factory prime coat on hollow metal is governed by [[sync/exterior-doors-and-frames]] and [[sync/doors-frames-and-hardware]]. This standard governs everything laid over those coats, and its warranty covers what it lays down and not the coat beneath. {note}

+## The Contractor shall obtain from each fabricator and door manufacturer the generic type and product identity of the shop or factory primer on every item scheduled for a field finish before the coating system schedule is submitted.

+## Where a substrate standard imposes a longer cure, a cleaner surface, or a tighter moisture limit than this standard, the more stringent requirement shall govern.

+# Referenced Standards {toc}

+## Materials, surface preparation, and application shall comply with the latest adopted edition of each of the following unless a specific edition is cited.

+## Where referenced standards conflict, the more stringent requirement shall govern unless the Architect directs otherwise in writing.

+| Standard | Title |

+|----------|-------|

+| MPI Architectural Painting Specification Manual | Master Painters Institute exterior system numbers, product categories, Approved Products List, and gloss levels |

+| ASTM D16 | 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 7/NACE No. 4 | Brush-Off Blast Cleaning |

+| SSPC-SP 10/NACE No. 2 | Near-White Metal Blast Cleaning |

+| SSPC-SP 11 | Power Tool Cleaning to Bare Metal |

+| SSPC-SP 13/NACE No. 6 | Surface Preparation of Concrete |

+| SSPC-SP 16 | Brush-Off Blast Cleaning of Coated and Uncoated Galvanized Steel, Stainless Steels, and Non-Ferrous Metals |

+| SSPC-PA 2 | Procedure for Determining Conformance to Dry Coating Thickness Requirements |

+| ASTM D4258 | Practice for Surface Cleaning Concrete for Coating |

+| ASTM D4259 | Practice for Abrading Concrete |

+| ASTM D4262 | Test Method for pH of Chemically Cleaned or Etched Concrete Surfaces |

+| ASTM D4263 | Test Method for Indicating Moisture in Concrete by the Plastic Sheet Method |

+| ASTM D4444 | Test Method for Laboratory Standardization and Calibration of Hand-Held Moisture Meters |

+| ASTM D3359 | Test Methods for Rating Adhesion by Tape Test |

+| ASTM D7091 | Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to Ferrous Metals and Nonmagnetic, Nonconductive Coatings Applied to Non-Ferrous Metals |

+| ASTM D523 | Test Method for Specular Gloss |

+| ASTM D2244 | Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates |

+| ASTM D3273 | Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental Chamber |

+| ASTM D3274 | Test Method for Evaluating Degree of Surface Disfigurement of Paint Films by Fungal or Algal Growth, or Soil and Dirt Accumulation |

+| ASTM D6904 | Practice for Resistance to Wind-Driven Rain for Exterior Coatings Applied on Masonry |

+| ASTM D6578 | Practice for Determination of Graffiti Resistance |

+| ANSI/SDI A250.10 | Test Procedure and Acceptance Criteria for Prime Painted Steel Surfaces for Steel Doors and Frames |

+| 40 CFR Part 59, Subpart D | National Volatile Organic Compound Emission Standards for Architectural Coatings |

+| OTC Model Rule for Architectural and Industrial Maintenance Coatings | Ozone Transport Commission |

+| CARB Suggested Control Measure for Architectural Coatings | California Air Resources Board |

+| SCAQMD Rule 1113 | Architectural Coatings |

+| 40 CFR Part 745 | Lead-Based Paint Poisoning Prevention in Certain Residential Structures |

+| 29 CFR 1926.62 | Lead in Construction |

+## The MPI manual assigns a product number to each generic coating type that passes a defined set of performance tests, and an exterior system number to each combination of substrate, primer, and finish, so a coating can be specified by performance class without naming a manufacturer. The Approved Products List names the products from competing manufacturers that have passed the tests for each number. The surface preparation standards once published by SSPC and NACE are now maintained by AMPP; the SP numbers remain in use and are cited here. {note}

+# Submittals {toc}

+## Action Submittals {toc}

+### The submittals listed below shall be reviewed and returned before any coating material is ordered or applied.

+- Product data for every primer, intermediate, and finish product, stating the generic resin type, the MPI product number where one applies, the substrates the product is published for, the wet and dry film thickness per coat, the spreading rate, the minimum and maximum recoat times, the application temperature and humidity limits, the dry-to-rain time, and the volatile organic compound content in grams per liter

+- Coating system schedule assigning to every exterior substrate and surface condition the surface preparation grade, the primer, the finish, the number of coats, the total dry film thickness, the sheen, and the MPI exterior system number where one applies

+- Color drawdowns of every color and sheen scheduled, on the substrate material or on a card the manufacturer publishes for the purpose, at the number of coats and film build the schedule requires, not smaller than 8 in. by 10 in.

+- Surface preparation plan for any abrasive blasting or coating removal, describing containment, dust control, protection of adjacent property, and disposal of spent abrasive and removed coating

+```datasheet

+label: Action Submittals Required

+type: checkbox

+options:

+ - "Product data for every coating product"

+ - "Coating system schedule by substrate"

+ - "Color drawdowns of every color and sheen"

+ - "Surface preparation plan for blasting or coating removal"

+default:

+ - "Product data for every coating product"

+ - "Coating system schedule by substrate"

+ - "Color drawdowns of every color and sheen"

+```

+### The Architect's acceptance of a drawdown shall establish the color and sheen standard for the surfaces it represents, and no material shall be tinted in bulk before the drawdown for that color is accepted.

+## Informational Submittals {toc}

+### The Contractor shall submit the following for record, without waiting for return, before the corresponding work begins.

+- Applicator qualification statement listing the comparable projects the Applicator Qualification article requires

+- The field coating manufacturer's written confirmation that each field system is compatible with the shop or factory primer identified on each item it will cover, and, where stucco is coated, with the stucco finish coat

+- The form of the daily environmental condition log, and the completed logs as the work proceeds

+- Safety data sheets for every product

+- The manufacturer's certification of the volatile organic compound content of every product against the regulatory basis selected under Volatile Organic Compounds

+- The record of mock-up acceptance, where a mock-up is required

+```datasheet

+label: Informational Submittals Required

+type: checkbox

+options:

+ - "Applicator qualification statement"

+ - "Primer and stucco compatibility confirmations"

+ - "Environmental condition logs"

+ - "Safety data sheets"

+ - "Volatile organic compound certifications"

+ - "Mock-up acceptance record"

+default:

+ - "Applicator qualification statement"

+ - "Primer and stucco compatibility confirmations"

+ - "Environmental condition logs"

+ - "Safety data sheets"

+ - "Volatile organic compound certifications"

+```

+## Closeout Submittals {toc}

+### The Contractor shall submit the following before final acceptance.

+- Record coating schedule stating, for every coated surface, the product and MPI number applied, the color name and tint formula, the sheen, the number of coats, and the dry film thickness measured

+- The manufacturer's published product warranty for every product that carries one, executed in the Owner's name where the manufacturer issues a project warranty

+- The Contractor's warranty under the Warranty section

+- Maintenance instructions stating the cleaning methods and cleaning agents the coating tolerates, the touch-up procedure, and the recoat interval for each system

+- The Owner's signed receipt for the extra stock delivered

+```datasheet

+label: Closeout Submittals Required

+type: checkbox

+options:

+ - "Record coating schedule"

+ - "Manufacturer product warranties"

+ - "Contractor warranty"

+ - "Maintenance and recoat instructions"

+ - "Extra stock receipt"

+default:

+ - "Record coating schedule"

+ - "Manufacturer product warranties"

+ - "Contractor warranty"

+ - "Maintenance and recoat instructions"

+ - "Extra stock receipt"

+```

+# Quality Assurance {toc}

+## Applicator Qualification {toc}

+### Exterior coating work shall be performed by an applicator that has completed exterior coating work of comparable substrate, system, and extent on not fewer than the number of projects indicated in the datasheet within the five years preceding the bid.

+```datasheet

+label: Minimum Comparable Projects Completed by the Applicator

+type: range

+unit: projects

+min: 0

+max: 10

+step: 1

+```

+### Where the manufacturer's published warranty on an elastomeric, two-component, or mineral silicate system is conditioned on application by an applicator the manufacturer has approved, the applicator shall hold that approval before the system is applied.

+### A value of zero waives the experience requirement and leaves qualification to the bid. Elastomeric, two-component polyurethane, and mineral silicate systems depend on mixing ratios, induction times, pot life, and wet-film control that general painting labor does not routinely practice, and an error in them shows up as a film failure under weather a season later rather than as a visible defect at acceptance, which is why the count is raised where those systems carry a large share of the work. {note}

+## MPI Listing {toc}

+### Each coating product shall meet the performance of the MPI product category assigned to its position in the coating system schedule, and whether listing on the MPI Approved Products List is required shall be as indicated in the datasheet.

+```datasheet

+label: MPI Approved Products List

+type: radio

+options:

+ - "Every product listed on the current MPI Approved Products List for its MPI number"

+ - "Products meeting the MPI performance category, listing not required"

+default: "Every product listed on the current MPI Approved Products List for its MPI number"

+```

+### Requiring the listing puts the performance test in MPI's laboratory and leaves the submittal reviewer to check a number against a list, and it limits the bid to the listed products of each manufacturer. Accepting unlisted products that meet the category admits regional and newly introduced products, and it moves the burden of judging the manufacturer's test data onto the submittal review. {note}

+## Single Source {toc}

+### The primer, intermediate, and finish coats within each coating system shall be products of one manufacturer, unless the datasheet permits coats from different manufacturers.

+```datasheet

+label: Coating System Sourcing

+type: radio

+options:

+ - "One manufacturer for every coat of each system"

+ - "Primer and finish from different manufacturers with written compatibility confirmation from both"

+default: "One manufacturer for every coat of each system"

+```

+### Where coats from different manufacturers are permitted, the Contractor shall obtain the written confirmation of both manufacturers that the coats are compatible over the specified substrate and preparation, and shall submit it before either coat is applied.

+### A manufacturer warrants the film it formulated as a system and declines a film built from another manufacturer's primer, so a mixed system carries only the Contractor's warranty. Shop and factory primers delivered on products from other trades are outside this rule; their compatibility with the field system is handled under the Shop and Factory Primers article. {note}

+## Field Mock-Up {toc}

+### The mock-up program shall be as indicated in the datasheet.

+```datasheet

+label: Mock-Up Program

+type: select

+options:

+ - "No mock-up required"

+ - "One mock-up of each coating system"

+ - "One mock-up of each coating system in each color"

+ - "One mock-up of each coating system on each substrate in each color"

+```

+### Each mock-up shall be applied on the actual substrate at a location the Architect designates, over an area not less than indicated in the datasheet, and shall show the full surface preparation, primer, and finish coats at the specified sheen and color.

+```datasheet

+label: Minimum Mock-Up Area

+type: range

+unit: ft²

+min: 25

+max: 400

+setpoints: [25, 50, 100, 200, 400]

+default: 100

+```

+### The mock-up shall be viewed in daylight before acceptance, and the accepted mock-up shall be the standard of appearance and workmanship for the production work.

+### The accepted mock-up shall remain in place and protected until the work is accepted, and may remain as part of the completed work where the Architect designates it in writing.

+### A drawdown shows a color on a flat card; a mock-up shows it on the texture of the wall, in the sun, next to the adjacent materials, which is where a stucco or block color is actually judged. One mock-up per system settles the appearance of the film; one per color adds the color judgment, which matters where several wall colors meet; one per substrate per color adds the texture difference between, for example, the same color on smooth concrete and on split-face block. Each step adds cost and schedule, and the program is sized to the number of colors and substrates the elevations carry. {note}

+## Pre-Application Conference {toc}

+### Whether a pre-application conference is held before exterior coating begins shall be as indicated in the datasheet.

+```datasheet

+label: Pre-Application Conference

+type: radio

+options:

+ - "Conference required before exterior coating begins"

+ - "No conference required"

+```

+### Where a conference is required, the Contractor shall convene it with the applicator, the coating manufacturer's representative, and the installers of the substrates to be coated, and the conference shall review the coating system schedule, the shop and factory primers identified, the surface preparation plan, the mock-up program, the weather limits, and the inspection hold points.

+### The conference is where the fabricator's primer, the stucco installer's cure, and the painter's system meet for the first time on most projects, and it is cheaper than the compatibility failure it prevents. It is held where several trades deliver primed or cementitious substrates to be coated, and skipped where the scope is a single substrate. {note}

+# Environmental and Service Conditions {toc}

+## Weather Limits During Application {toc}

+### Coatings shall not be applied when the air temperature or the surface temperature is below the minimum indicated in the datasheet, or above the maximum the manufacturer publishes for the product.

+```datasheet

+label: Minimum Air and Surface Temperature During Application

+type: range

+unit: °F

+min: 35

+max: 50

+setpoints: [35, 40, 45, 50]

+default: 50

+```

+### The temperature limits shall be maintained from the start of application until the coat has reached the manufacturer's published dry-to-recoat time.

+### Below its minimum film-forming temperature a waterborne coating does not coalesce: the polymer particles never fuse into a continuous film, and the coat looks acceptable when applied and fails early. Conventional waterborne products hold that minimum at 50°F; formulations rated to 35°F are available from several manufacturers at a premium and with a longer dry time, and they are selected where the schedule puts the work into a shoulder season. Above the published maximum, water or solvent flashes off before the film levels, producing dry spray and lap marks, and a surface in direct sun can exceed the air temperature by 30°F or more. {note}

+### Coatings shall not be applied when the relative humidity exceeds the value indicated in the datasheet.

+```datasheet

+label: Maximum Relative Humidity During Application

+type: range

+unit: '%'

+min: 70

+max: 95

+step: 5

+default: 85

+```

+### Coatings shall not be applied unless the surface temperature is at least 5°F above the dew point, and application shall stop when the margin closes or condensation forms during the dry time.

+### Coatings shall not be applied when rain, fog, frost, or dew is present on the surface or is forecast within the manufacturer's published dry-to-rain time for the coat.

+### Coatings shall not be applied in wind that causes dry spray, carries overspray onto adjacent surfaces or property, or deposits dust or debris in the wet film.

+### The Contractor shall measure and record the air temperature, the surface temperature, the relative humidity, and the dew point at the start of each application period and at intervals not exceeding four hours while application continues, and shall include the record in the informational submittals.

+## Substrate Moisture and Cure {toc}

+### Concrete, concrete masonry, and stucco shall have cured not less than the number of days indicated in the datasheet before a coating is applied, unless the coating manufacturer publishes a shorter interval for the product and a moisture test under this article confirms the substrate is within the manufacturer's limit.

+```datasheet

+label: Minimum Cure of Cementitious Substrates Before Coating

+type: range

+unit: days

+min: 7

+max: 28

+setpoints: [7, 14, 21, 28]

+default: 28

+```

+### Cementitious substrates shall be tested for moisture by ASTM D4263 before coating and shall show no condensation beneath the sheet; where an electronic moisture meter calibrated to ASTM D4444 is used in its place, the reading shall not exceed the value indicated in the datasheet.

+```datasheet

+label: Maximum Moisture Reading of Cementitious Substrates

+type: range

+unit: '%'

+min: 8

+max: 16

+step: 1

+default: 12

+```

+### The surface pH of concrete, masonry, and stucco shall be tested by ASTM D4262 before priming, and a surface whose pH exceeds the primer manufacturer's published limit shall be allowed to cure further or shall receive an alkali-resistant primer the manufacturer publishes for that pH.

+### Exterior wood shall not be coated when its moisture content, measured with a meter calibrated to ASTM D4444, exceeds the value indicated in the datasheet.

+```datasheet

+label: Maximum Moisture Content of Wood Before Coating

+type: range

+unit: '%'

+min: 12

+max: 19

+step: 1

+default: 15

+```

+### Fresh concrete and stucco carry free water and a surface alkalinity that attack a film from behind: the water blisters it and the alkali saponifies an alkyd binder and burns the color out of a pigment. Twenty-eight days is the age at which ordinary portland cement surfaces have dropped to a pH and a moisture level most primers tolerate; the shorter intervals are used with primers the manufacturer publishes for green concrete and are confirmed by test rather than by the calendar. Wood above about 15 percent moisture pushes water through a new film as it dries and lifts it. {note}

+# Coating Systems by Substrate {toc}

+## System Selection {toc}

+### The coating system for each substrate shall be as indicated in the datasheets of this section, and the coating system schedule shall assign a system to every exterior surface scheduled for coating.

+### Each system shall consist of the primer this standard or the manufacturer requires for the substrate, plus the number of finish coats indicated under Number of Coats and Film Thickness.

+### No single exposure fact selects the system. A site within a few miles of salt water, downwind of an industrial stack, or under a tree canopy that keeps a north wall damp changes which option in each datasheet below holds its color and film, and the notes under each field state the trade-off against those conditions so the engineer can read the site against them. {note}

+## Concrete, Concrete Masonry, and Stucco {toc}

+### The finish coat system on concrete, concrete masonry, and stucco shall be as indicated in the datasheet.

+```datasheet

+label: Finish System on Concrete, Masonry, and Stucco

+type: select

+options:

+ - "Exterior 100 percent acrylic latex"

+ - "Elastomeric acrylic"

+ - "High-build acrylic"

+ - "Waterborne acrylic-epoxy"

+ - "Mineral silicate paint"

+default: "Exterior 100 percent acrylic latex"

+```

+### A 100 percent acrylic latex is the breathable decorative film on sound cementitious walls: it holds color under ultraviolet, lets vapor out of the wall, and is the lowest-cost system to apply and to recoat. An elastomeric acrylic is applied at several times that thickness and stretches across hairline cracks and resists wind-driven rain, which is why it is selected on stucco and on walls that have cracked or leaked; it is less permeable, so it is kept off walls that get wet from behind, and it shows substrate texture less and dirt more. A high-build acrylic fills texture and pinholes on rough block and board-formed concrete at a thickness between the two. A waterborne acrylic-epoxy resists scrubbing and staining at a loading dock or a trash enclosure and chalks faster than acrylic in full sun. A mineral silicate paint bonds chemically to the mineral substrate, is fully vapor-open, and does not peel, which is why it is selected on historic masonry and unpainted lime or cement substrates; it cannot be applied over an existing organic film, and it is sold by fewer manufacturers. {note}

+### Alkyd coatings shall not be applied to concrete, concrete masonry, or stucco, because the alkalinity of the substrate saponifies the alkyd binder.

+### The primer on concrete and stucco shall be as indicated in the datasheet.

+```datasheet

+label: Primer on Concrete and Stucco

+type: select

+options:

+ - "Alkali-resistant acrylic primer-sealer"

+ - "Penetrating masonry surface conditioner"

+ - "First coat of the finish material applied as a self-primer"

+```

+### An alkali-resistant acrylic primer-sealer seals a porous surface, evens the absorption so the finish dries uniformly, and tolerates a pH higher than a finish coat does, which is why it is selected on new stucco and concrete coated near the end of the cure period. A penetrating surface conditioner binds a chalky or weathered surface that would otherwise shed a film, and it is selected on recoat work and on stucco that has weathered unpainted for a season. Elastomeric and some high-build systems are published as self-priming on a sound, cured surface, and the first coat of the finish then serves as the primer and saves a product and a day; the manufacturer's data sheet states when that is permitted, and the pH test governs where the substrate is young. {note}

+### Whether concrete masonry receives a block filler shall be as indicated in the datasheet.

+```datasheet

+label: Block Filler on Concrete Masonry

+type: radio

+options:

+ - "High-build block filler before the primer or first finish coat"

+ - "No block filler"

+default: "High-build block filler before the primer or first finish coat"

+```

+### Block filler shall be applied by roller or by spray with back-rolling, in the quantity needed to fill the surface voids of the masonry and present a continuous surface to the coat that follows.

+### Concrete masonry is open-celled, and finish coats applied straight to it sink into the voids, leave pinholes, and never form a continuous weather film. A block filler closes the texture at a fraction of the finish material's cost per mil. It is omitted where the units were factory prefilled or sealed, where a high-build finish system is itself published to fill the texture, or where the open texture is the appearance the design wants and a water repellent rather than a film is specified under the masonry standard. {note}

+### Elastomeric coatings shall be applied in not fewer than two coats to a total dry film thickness not less than indicated in the datasheet, and shall be products tested for wind-driven rain resistance by ASTM D6904.

+```datasheet

+label: Minimum Total Dry Film Thickness of Elastomeric Coatings

+type: range

+unit: mils

+min: 8

+max: 24

+setpoints: [8, 10, 12, 14, 16, 20, 24]

+```

+### An elastomeric film bridges cracks only at the thickness the manufacturer tested it at, and the published values run from about 10 mils for a two-coat decorative elastomeric to 20 mils and more for a system warranted against water intrusion. The thickness is set from the product data of the system selected and from whether the wall has an active crack pattern to bridge. {note}

+### Coatings shall not be applied to stucco until the Contractor has obtained the stucco finish coat manufacturer's written confirmation that the finish coat is compatible with the coating system, as [[sync/plaster-and-stucco]] requires.

+### Where architectural precast concrete is scheduled for a field coating, the Contractor shall confirm with the precast supplier that no sealer or water repellent has been applied to the units under [[sync/architectural-precast-concrete]] that the primer manufacturer does not publish the primer as bonding to.

+## Ferrous Metal {toc}

+### Bare ferrous metal, and the bare areas of shop-primed or factory-primed ferrous metal, shall be solvent cleaned to SSPC-SP 1 and then prepared to the grade indicated in the datasheet before priming.

+```datasheet

+label: Surface Preparation Grade for Bare Ferrous Metal

+type: select

+options:

+ - "SSPC-SP 2, Hand Tool Cleaning"

+ - "SSPC-SP 3, Power Tool Cleaning"

+ - "SSPC-SP 11, Power Tool Cleaning to Bare Metal"

+ - "SSPC-SP 7, Brush-Off Blast Cleaning"

+ - "SSPC-SP 6, Commercial Blast Cleaning"

+ - "SSPC-SP 10, Near-White Metal Blast Cleaning"

+```

+### Hand and power tool cleaning remove loose rust, loose mill scale, and loose coating and leave the tight material in place; they are the grades a field crew reaches on a railing, a lintel, or a door frame without containment, and they serve an alkyd or acrylic primer that tolerates a tight residue. Power tool cleaning to bare metal removes everything but leaves no anchor profile, which an epoxy primer accepts and a zinc-rich primer does not. Brush-off blast removes loose material and roughens the surface with the least abrasive and containment. Commercial blast removes all but staining and gives the profile an epoxy primer bonds to, and near-white blast is the grade zinc-rich primers and the long-life systems for coastal and industrial exposure are published for; both require containment and disposal planned under the surface preparation plan. {note}

+### Solvent cleaning to SSPC-SP 1 shall precede every other preparation grade, because abrasive or mechanical cleaning over oil or grease drives the contaminant into the profile.

+### The field primer on ferrous metal shall be as indicated in the datasheet.

+```datasheet

+label: Field Primer on Ferrous Metal

+type: select

+options:

+ - "Rust-inhibitive alkyd primer"

+ - "Waterborne acrylic rust-inhibitive primer"

+ - "Epoxy primer"

+ - "Organic zinc-rich primer"

+```

+### A rust-inhibitive alkyd primer wets a hand-cleaned surface and tolerates tight rust, and it is restricted or unavailable where the volatile organic compound basis is strict. A waterborne acrylic rust-inhibitive primer meets every current limit, dries fast, and needs a cleaner, drier surface and a warmer day. An epoxy primer builds a thicker barrier and bonds a polyurethane finish, and it needs a blast-cleaned surface and a recoat window the schedule has to respect. An organic zinc-rich primer protects the steel galvanically at a scratch and is the primer under the systems selected for coastal and industrial sites, at the cost of near-white blasting and a two-component mix. {note}

+### Epoxy primers shall be applied only over a surface cleaned to SSPC-SP 6 or cleaner, and zinc-rich primers only over a surface cleaned to SSPC-SP 10 or cleaner, unless the primer manufacturer publishes a less stringent grade for the product.

+## Metal Finish Coats {toc}

+### The finish coat system on ferrous, galvanized, and non-ferrous metal shall be as indicated in the datasheet.

+```datasheet

+label: Finish System on Metal

+type: select

+options:

+ - "Exterior acrylic latex, direct-to-metal grade"

+ - "Alkyd enamel"

+ - "Waterborne acrylic-urethane"

+ - "Two-component aliphatic polyurethane over an epoxy primer"

+ - "Waterborne acrylic-epoxy"

+```

+### An exterior acrylic latex of direct-to-metal grade holds its color and gloss under ultraviolet, tolerates the movement of a door or a railing, and meets every volatile organic compound limit, and it marks and burnishes more easily than a harder resin. An alkyd enamel levels to the smoothest brushed finish and hardens over weeks, chalks and yellows in sun, and is restricted where the volatile organic compound basis is strict. A waterborne acrylic-urethane sits between them in hardness and gloss retention at a waterborne volatile organic compound content. A two-component aliphatic polyurethane over an epoxy primer holds gloss and color longest, resists abrasion and salt, and is the system selected for railings and exposed steel on coastal and industrial sites; it requires the preparation its primer demands, a two-component mix, and a trained applicator. A waterborne acrylic-epoxy resists scrubbing and staining on a frequently cleaned door or frame and chalks in full sun. {note}

+### Where a two-component aliphatic polyurethane finish is selected, the primer shall be an epoxy or zinc-rich primer the finish manufacturer publishes for the system, and the surface preparation shall be the grade that primer requires.

+### Where a metal surface sees chemical splash, immersion, or industrial washdown, its coating system is selected under [[sync/high-performance-coatings]] rather than from this datasheet. {note}

+## Galvanized Steel {toc}

+### Galvanized steel shall be solvent cleaned to SSPC-SP 1 and then cleaned of its passivating treatment, storage oils, and white rust by the method the primer manufacturer publishes, and shall be given a profile by SSPC-SP 16 where the primer manufacturer requires one, before priming.

+### The primer on galvanized steel shall be as indicated in the datasheet.

+```datasheet

+label: Primer on Galvanized Steel

+type: select

+options:

+ - "Waterborne acrylic primer formulated for galvanizing"

+ - "Vinyl wash primer"

+ - "Epoxy primer formulated for galvanizing"

+ - "Acrylic direct-to-metal finish applied as its own primer"

+default: "Waterborne acrylic primer formulated for galvanizing"

+```

+### New galvanizing carries a chromate passivation and rolling oils that shed ordinary primers, and zinc saponifies an alkyd binder. A waterborne acrylic primer formulated for galvanizing bonds to a cleaned zinc surface without etching, meets every volatile organic compound limit, and is what most manufacturers publish under their acrylic and acrylic-urethane finishes. A vinyl wash primer etches the zinc chemically and is the traditional base under an alkyd or polyurethane system where the strict volatile organic compound bases do not apply. An epoxy primer formulated for galvanizing is the base under a two-component polyurethane finish where that system is selected for the exposure. Several direct-to-metal acrylics are published as self-priming on cleaned galvanizing and save a coat on weathered galvanizing that has lost its passivation; the manufacturer's data sheet states whether new, bright galvanizing is included. {note}

+### Alkyd primers and alkyd finish coats shall not be applied directly to galvanized steel.

+### The factory-primed curtains, hoods, and guides of coiling doors under [[sync/overhead-coiling-doors]] and the factory-primed sections of sectional doors under [[sync/sectional-overhead-doors]], where scheduled for a field finish, shall receive the finish system selected under Metal Finish Coats over the factory primer, after the compatibility confirmation the Shop and Factory Primers article requires.

+## Aluminum and Other Non-Ferrous Metal {toc}

+### Mill-finish aluminum, copper alloys, and other non-ferrous metals scheduled for a field finish shall be solvent cleaned to SSPC-SP 1 and primed as indicated in the datasheet.

+```datasheet

+label: Primer on Aluminum and Other Non-Ferrous Metal

+type: select

+options:

+ - "Waterborne acrylic bonding primer for non-ferrous metal"

+ - "Vinyl wash primer"

+ - "Epoxy primer formulated for non-ferrous metal"

+ - "Not applicable, no non-ferrous metal scheduled for a field finish"

+```

+### A waterborne acrylic bonding primer wets a cleaned aluminum surface and carries an acrylic or acrylic-urethane finish at the lowest volatile organic compound content. A vinyl wash primer etches the oxide and is the base under an alkyd or polyurethane finish. An epoxy primer formulated for non-ferrous metal is the base under a two-component polyurethane system. Field painting of mill aluminum is uncommon because most architectural aluminum arrives anodized or factory coated; the field selection covers mill-finish trim, conduit, louvers, and repairs. {note}

+### Factory-finished aluminum and other factory-finished non-ferrous metal shall not be field painted unless the Contract Documents direct it, because a field coating over an anodic or fluoropolymer finish voids the finish warranty and does not bond without a treatment the finish manufacturer approves.

+## Wood {toc}

+### The finish type on exterior wood shall be as indicated in the datasheet.

+```datasheet

+label: Finish Type on Exterior Wood

+type: select

+options:

+ - "Opaque 100 percent acrylic latex paint"

+ - "Opaque alkyd paint"

+ - "Solid-color acrylic stain"

+ - "Semi-transparent penetrating stain"

+ - "Transparent water-repellent finish"

+ - "Film-forming exterior clear finish"

+```

+### An opaque acrylic paint builds a flexible film that moves with the wood, holds color, and lasts longest among the opaque finishes on siding and trim. An opaque alkyd paint penetrates weathered wood and levels on trim and doors, and it embrittles and chalks sooner and is restricted where the volatile organic compound basis is strict. A solid-color stain hides the grain while showing the texture and fails by erosion rather than by peeling, so it recoats without scraping. A semi-transparent penetrating stain shows the grain, lasts two to four years on a weather face, and recoats by cleaning and reapplying. A transparent water-repellent finish keeps the natural color for a season or two and is the finish for wood intended to weather to gray with less checking. A film-forming clear finish shows the wood at its best and fails by peeling under ultraviolet within a few years on any face the sun reaches, so it is kept to protected soffits and doors under a deep overhang. {note}

+### The primer under an opaque finish on exterior wood shall be as indicated in the datasheet.

+```datasheet

+label: Primer on Exterior Wood Under an Opaque Finish

+type: radio

+options:

+ - "Alkyd stain-blocking exterior wood primer"

+ - "Acrylic stain-blocking exterior wood primer"

+```

+### An alkyd wood primer penetrates and seals the grain, blocks tannin and extractive bleed on cedar and redwood more completely, and takes longer to dry. An acrylic wood primer stays flexible with the wood, meets the strict volatile organic compound bases, and blocks bleed well on most species with a second coat on the heaviest-bleeding ones. {note}

+### Knots, sap streaks, and resinous areas shall be spot sealed with a stain-blocking sealer before the primer, and nail holes and surface defects shall be filled after priming and before the finish coats.

+### Cut ends and end grain of wood siding and trim exposed by site cutting shall be primed before the piece is installed where the end is accessible, and sealed with the primer where it becomes accessible only after installation.

+### Wood doors delivered unfinished or factory sealed under [[sync/wood-doors]] shall be finished on all six surfaces, including the top and bottom edges and every cutout, within the interval after hanging that the door manufacturer publishes.

+### Factory-primed wood and fiber-cement siding and trim shall receive the finish coats within the exposure period the primer manufacturer publishes for the factory primer, and the factory primer shall be spot primed where it is cut, abraded, or weathered beyond that period.

+### Fiber-cement siding and trim shall receive a 100 percent acrylic latex finish, and unprimed fiber cement shall receive an alkali-resistant acrylic primer before the finish coats.

+### Fiber-cement manufacturers condition their finish warranties on a 100 percent acrylic topcoat and publish an alkali-resistant acrylic primer for unprimed material, because the cement content of the board attacks other binders the way fresh concrete does, and an elastomeric film is too impermeable for the board. {note}

+### A dark color on a wood or fiber-cement face in direct sun raises the surface temperature by tens of degrees, which drives moisture out of the wood faster, opens checks, and shortens the film's life; the finish schedule limits the light reflectance value of colors on such faces where the manufacturer's warranty does. {note}

+## Previously Painted Surfaces {toc}

+### Before a previously painted surface is recoated, the Contractor shall assess the soundness of the existing coating and test its adhesion by ASTM D3359 at not fewer than three locations per substrate and existing coating type, plus one location per additional 1,000 ft² of that surface.

+### The disposition of the existing coating shall be as indicated in the datasheet.

+```datasheet

+label: Disposition of Existing Coating

+type: radio

+options:

+ - "Spot preparation of failed areas and overcoat of the sound film"

+ - "Complete removal of the existing coating to the substrate"

+```

+### Overcoating a sound film costs a fraction of removal and is what most recoat work does: the failed areas are scraped and feathered, the sound film is cleaned and dulled, and the new system goes over both. Complete removal is selected where the adhesion test fails across the surface, where the existing film is an incompatible type such as an aged alkyd under a strict volatile organic compound basis that forbids its match, where the film has built up to the point that it cracks, or where a mineral silicate or elastomeric system that cannot go over an organic film is selected. {note}

+### Loose, peeling, blistered, cracked, and alkali-burned coating shall be removed to a sound edge, and the edge shall be feathered so that the repair does not telegraph through the finish.

+### Chalk shall be washed from the surface, glossy sound film shall be dulled by sanding or by a deglossing method the manufacturer publishes, and the sound film shall be cleaned of mildew, soil, and oil before priming.

+### Where the existing coating fails the adhesion test at any location, the Contractor shall report the result to the Architect before proceeding, and the Architect shall determine the extent of the surface to be removed.

+### A test patch of the proposed system shall be applied over the prepared existing coating, cured not less than seven days, and tested for adhesion by ASTM D3359 before the system is applied to the rest of the surface.

+### In a building constructed before 1978, the existing coating shall be tested for lead before any sanding, scraping, or blasting disturbs it, and a coating found to contain lead shall be handled under [[sync/hazardous-material-abatement]], 40 CFR Part 745 where the building is target housing or a child-occupied facility, and 29 CFR 1926.62.

+## Anti-Graffiti and Mildew-Resistant Finishes {toc}

+### Whether an anti-graffiti coating is applied over the finish shall be as indicated in the datasheet.

+```datasheet

+label: Anti-Graffiti Coating

+type: select

+options:

+ - "None"

+ - "Sacrificial anti-graffiti coating"

+ - "Non-sacrificial anti-graffiti coating"

+default: "None"

+```

+### A sacrificial anti-graffiti coating is a clear wax or polysaccharide film that is removed with hot water along with the graffiti and reapplied, which keeps the cost per application low and the maintenance recurring. A non-sacrificial coating is a clear polyurethane, siloxane, or fluoropolymer film that resists repeated cleaning with solvents and stays in place, at a higher first cost and with a sheen and a darkening of the color beneath that the mock-up has to show. Both are applied to the lower portion of walls exposed to the public way, and the extent is set by the elevations. {note}

+### Where an anti-graffiti coating is selected, its extent shall be [[drawing: as indicated on the exterior elevations]], and the product shall be tested by ASTM D6578 and published by its manufacturer as compatible with the finish coat beneath it.

+### Whether the finish coats on cementitious and wood substrates are a mildew-resistant formulation shall be as indicated in the datasheet.

+```datasheet

+label: Mildew Resistance of Finish Coats

+type: radio

+options:

+ - "Mildew-resistant formulation tested by ASTM D3273 and rated by ASTM D3274"

+ - "No mildew-resistance requirement"

+default: "Mildew-resistant formulation tested by ASTM D3273 and rated by ASTM D3274"

+```

+### Most exterior finish coats carry a mildewcide as formulated, and the requirement makes the claim testable rather than adding a product. It is waived where the Owner's environmental program excludes biocidal additives, and it is held where a shaded, damp, or north-facing elevation shows mildew on the existing finish. {note}

+# Sheen, Coats, and Film Thickness {toc}

+## Sheen {toc}

+### The sheen of finish coats on wall fields of concrete, masonry, stucco, and siding shall be as indicated in the datasheet, expressed as the MPI gloss level.

+```datasheet

+label: Sheen of Finish Coats on Wall Fields

+type: select

+options:

+ - "G1, flat"

+ - "G2, velvet"

+ - "G3, eggshell"

+ - "G4, satin"

+ - "G5, semi-gloss"

+```

+### The sheen of finish coats on trim, doors, frames, railings, and other metal shall be as indicated in the datasheet, expressed as the MPI gloss level.

+```datasheet

+label: Sheen of Finish Coats on Trim, Doors, and Metal

+type: select

+options:

+ - "G3, eggshell"

+ - "G4, satin"

+ - "G5, semi-gloss"

+ - "G6, gloss"

+ - "G7, high gloss"

+default: "G5, semi-gloss"

+```

+### Gloss shall be measured by ASTM D523 at 60 degrees, and sheen at 85 degrees, against the ranges the MPI gloss levels define.

+### A flat or velvet finish hides the texture variation, patching, and lap marks of a large stucco or block field and soils fastest; a satin or semi-gloss finish sheds dirt and rain and shows every trowel mark and patch. On trim and metal the higher levels wash and resist handling and show the substrate's dents and weld grinding, and a gloss or high gloss alkyd or polyurethane is selected on doors and railings where that appearance is wanted. Elastomeric coatings are published in flat and low-sheen levels, and a sheen above velvet is not available in most elastomeric lines. {note}

+## Number of Coats and Film Thickness {toc}

+### Each coating system shall consist of its primer plus the number of finish coats indicated in the datasheet.

+```datasheet

+label: Number of Finish Coats Over the Primer

+type: range

+unit: coats

+min: 1

+max: 3

+step: 1

+default: 2

+```

+### Each coat shall be applied at not less than the spreading rate and dry film thickness the manufacturer publishes for the product, and the completed system shall meet the total dry film thickness stated in the coating system schedule.

+### Where the number of coats indicated does not produce complete hide and uniform color and sheen, the Contractor shall apply additional coats at no change in the Contract Sum until it does.

+### Two finish coats over a primer build the film thickness the manufacturer's weathering data assume and hide the primer on most colors. A single finish coat serves a self-priming elastomeric or high-build system published for one finish coat over its own first coat, and a solid-color or semi-transparent stain applied as one coat. A third finish coat is reached for on a deep or saturated color whose pigment hides poorly, on a porous block field that drinks the first coat, and where the system's published thickness cannot be reached in two. {note}

+# Color {toc}

+## Colors of every coated surface shall be [[drawing: as indicated on the exterior finish schedule]], and the Contractor shall not select or substitute a color.

+## Each color shall match the accepted drawdown under the Action Submittals article, and a custom or deep-tone color shall additionally be confirmed on the mock-up where one is required before bulk material is tinted.

+## Where the Architect and the Contractor disagree whether a cured film matches the accepted drawdown, the color difference measured by ASTM D2244 with a spectrophotometer shall not exceed the value indicated in the datasheet, and where no value is indicated the Architect's determination shall govern.

+```datasheet

+label: Maximum Color Difference From the Accepted Drawdown

+type: range

+unit: ΔE

+min: 1

+max: 4

+step: 0.5

+```

+## Bulk-tinted material of one color from different batches shall be boxed into one container and mixed before application on any continuous surface.

+## Deep and saturated colors fade and chalk faster than light ones, require the third coat the Number of Coats article describes, and are not available in every product line; elastomeric and fiber-cement manufacturers publish a minimum light reflectance value below which their warranty does not apply. A tolerance of about 1 ΔE is at the limit of what a tinting machine repeats and is bought for a color-critical facade; 2 ΔE is the difference a trained eye sees side by side; above 3 ΔE a repair is visible from the sidewalk. {note}

+# Volatile Organic Compounds {toc}

+## Every coating shall comply with the volatile organic compound limits in force at the project location, and the regulatory basis against which the submittals demonstrate compliance shall be as indicated in the datasheet.

+```datasheet

+label: Volatile Organic Compound Limit Basis

+type: select

+options:

+ - "EPA national architectural coatings rule, 40 CFR Part 59 Subpart D"

+ - "OTC model rule as adopted by the state"

+ - "CARB Suggested Control Measure as adopted by the air district"

+ - "SCAQMD Rule 1113"

+```

+## Where a limit stricter than the selected basis is in force at the project location, the stricter limit shall govern, and the Contractor shall confirm the limits in force before material is ordered.

+## The product data shall state the volatile organic compound content of each product in grams per liter, less water and exempt compounds, as the selected basis defines it.

+## The federal rule is the floor everywhere in the United States and permits alkyd primers and enamels at contents the state rules do not. The Ozone Transport Commission model rule, adopted in most northeastern and mid-Atlantic states, and the California Air Resources Board measure, adopted by most California air districts and by several other states, lower the limits for flats, non-flats, primers, and stains to levels that most alkyd products do not meet. SCAQMD Rule 1113 is the strictest and is the basis a project outside southern California selects when it wants the lowest-emitting product lines, which every national manufacturer stocks, or when a green-building rating system credits it. The selected basis changes which options in the primer and finish datasheets above remain procurable. {note}

+# Surface Preparation {toc}

+## Cleaning and Repair Common to All Substrates {toc}

+### Surface preparation of each surface shall be completed and inspected under the Inspection Hold Points article before any primer is applied to it.

+### Every surface to be coated shall be clean, dry, sound, and free of dust, dirt, oil, grease, form-release agent, curing compound, efflorescence, laitance, chalk, mildew, rust, mill scale, loose or failing coating, and any other contaminant that would impair adhesion.

+### Mildew shall be killed and removed with a solution the coating manufacturer publishes for the purpose, the surface shall be rinsed and allowed to dry, and the source of the moisture that supported it shall be reported to the Architect.

+### Efflorescence shall be removed by dry brushing followed by washing, and the surface shall not be coated until efflorescence has stopped reappearing after cleaning.

+### Cracks wider than 1/16 in. in concrete, masonry, and stucco shall be routed and sealed with an elastomeric sealant under [[sync/joint-sealants]] that the coating manufacturer publishes as paintable, before the primer is applied.

+### Holes, voids, tie holes, and spalls in cementitious substrates shall be filled with a cementitious or polymer-modified patching compound, cured, and profiled to match the adjacent surface before priming.

+### Hardware, fixtures, signs, cover plates, and other items not scheduled for coating shall be removed or masked before application and reinstalled or unmasked after the finish has cured, and fire door labels, nameplates, and equipment data plates shall not be coated.

+### Surfaces, landscaping, vehicles, and property adjacent to the work shall be protected from drips, spatter, and overspray, and any that is deposited shall be removed by the Contractor at its own cost without damage to the surface it landed on.

+### A surface that is clean but wet, or dry but chalky, or sound but glossy, fails a new film in a different way, and the preparation steps above are each aimed at one of those failures. Mildew that is painted over keeps growing and lifts the film; efflorescence that is painted over pushes the film off as the salts recrystallize; a crack that is bridged by paint alone reopens with the first thermal cycle. {note}

+## Concrete, Masonry, and Stucco Preparation {toc}

+### Sound, open-textured concrete, masonry, and stucco shall be cleaned by the methods of ASTM D4258.

+### Smooth, glazed, or burnished concrete, and concrete carrying a form-release agent or a curing compound, shall be abraded by ASTM D4259 or prepared by SSPC-SP 13 to a uniformly textured, absorbent surface.

+### The Contractor shall confirm the removal of form-release agents and curing compounds by observing that water sprinkled on the surface is absorbed rather than beaded, before priming.

+### Where an existing coating is being removed from a cementitious substrate, the removal method shall be one SSPC-SP 13 describes, and the surface shall be cleaned of the removal residue by ASTM D4258 before priming.

+### A curing compound or a form-release agent leaves a film that no primer bonds through, and it is invisible on a dry wall; the water test shows it in a minute. The abrasive and mechanical methods roughen a surface too dense to absorb a primer and remove a contaminated skin, and they are planned with containment where the dust reaches the public. {note}

+## Shop and Factory Primers {toc}

+### Before a finish system is applied over a shop or factory primer, the Contractor shall obtain the field coating manufacturer's written confirmation that the finish system is compatible with that primer, as the Informational Submittals article requires.

+### Where compatibility cannot be confirmed, the Contractor shall apply a tie coat the finish manufacturer publishes for the purpose over the primer, or shall remove the primer and prime the surface under the Ferrous Metal or Galvanized Steel article, as the Architect directs.

+### Damaged shop or factory primer, field welds, bolted connections, field-cut edges, and bare areas shall be cleaned to the grade selected under Ferrous Metal and spot primed with a primer the field coating manufacturer publishes as compatible with both the shop primer and the finish, before the finish coats are applied.

+### Shop-primed or factory-primed steel that has stood exposed longer than the primer manufacturer's published exposure period, or that shows rust bleeding through the primer, shall be cleaned to the grade selected under Ferrous Metal and reprimed before the finish coats.

+### Hollow metal doors and frames delivered with a factory primer to ANSI/SDI A250.10 shall be cleaned of handling soil, sanded smooth where the primer is rough or runs, spot primed where the primer is damaged, and finished with the system selected under Metal Finish Coats.

+### A shop primer is a shipping coat formulated to be covered, and its exposure life is weeks to months. A finish applied over a primer it does not wet lifts at the interface, and when it does, the fabricator points to the painter and the painter to the fabricator; the written compatibility confirmation and the identity of the primer on the shop drawings are what make one party answerable. [[sync/structural-steel-framing]] has the fabricator identify its primer for this reason and, where the field finish is known at shop drawing time, apply one the finish manufacturer publishes as compatible. {note}

+# Coating Application {toc}

+## Application Methods {toc}

+### The application method shall be as indicated in the datasheet.

+```datasheet

+label: Application Method

+type: radio

+options:

+ - "Spray application permitted, with back-rolling on porous substrates"

+ - "Brush and roller only"

+default: "Spray application permitted, with back-rolling on porous substrates"

+```

+### Spray-applied coatings on concrete, masonry, stucco, and wood shall be back-rolled or back-brushed into the surface while the coat is wet.

+### The first coat on a porous substrate shall be worked into the surface so that it wets the voids and the texture rather than bridging them.

+### Spray lays a coat down fast and evenly on a large field and is the only practical method on a textured elastomeric; without back-rolling it bridges the texture of block and rough concrete and leaves pinholes and voids that let water behind the film, and it drifts onto whatever is downwind. Brush and roller alone are selected where overspray cannot be contained, on occupied sites and near parked vehicles, and on trim and railings where spray wastes more material than it applies. {note}

+## Recoat Windows and Film Continuity {toc}

+### Each coat shall dry for not less than the manufacturer's published minimum recoat time before the next coat is applied, and where the manufacturer publishes a maximum recoat time the next coat shall be applied within it or the surface shall be abraded or tie-coated as the manufacturer publishes.

+### Two-component materials shall be mixed in the published ratio, allowed the published induction time, and applied within the published pot life, and material that has exceeded its pot life shall be discarded.

+### The completed film shall be continuous and uniform in color, sheen, and thickness, free of runs, sags, drips, holidays, pinholes, dry spray, lap marks, brush marks, and embedded debris when viewed in daylight from a distance of 10 ft.

+### The Contractor shall maintain a wet edge and shall complete each wall plane, or each plane to a natural break such as a corner, a joint, or a change of material, in one continuous operation.

+### Recoating too soon traps water or solvent under the new coat and blisters it; recoating an epoxy or polyurethane after its window closes puts a new coat on a surface too hard to bond to, and the window on those products is measured in days. Lap marks appear where a dried edge is overlapped on a sunny wall, which is why a plane is finished to a break rather than to the end of the day. {note}

+## Touch-Up and Final Cleaning {toc}

+### After the work of other trades is complete, the Contractor shall touch up abrasions, scratches, and damage to the coated surfaces with the same product, color, and batch used on the surface, applied by the same method.

+### Where a touch-up is visible in daylight from 10 ft, the Contractor shall recoat the surface to the nearest natural break.

+### The Contractor shall remove spatter, drips, and overspray from every surface not scheduled for coating, and shall remove its materials, containers, and debris from the site at completion.

+# Testing {toc}

+## Film Thickness Verification {toc}

+### The coating thickness verification program shall be as indicated in the datasheet.

+```datasheet

+label: Coating Thickness Verification

+type: select

+options:

+ - "Wet film gauge readings during application on every substrate"

+ - "Wet film gauge readings plus dry film measurement to SSPC-PA 2 on metal"

+ - "Dry film measurement to SSPC-PA 2 on metal by an independent coating inspector"

+```

+### Dry film thickness on metal shall be measured with a gauge conforming to ASTM D7091, and dry film thickness on non-metallic substrates shall be verified by wet film gauge readings during application correlated to the product's volume solids.

+### Where a measured area is below the specified dry film thickness, the Contractor shall apply additional coats to that area until it conforms, at no change in the Contract Sum.

+### A wet film gauge read during application is the only thickness check available on stucco, block, and wood, and it is what architectural painting relies on. Dry film measurement to SSPC-PA 2 on metal proves the film on railings, doors, and exposed steel to a statistical sampling plan and is selected where a two-component or coastal system is being paid for. An independent inspector adds a party with no stake in the result and is selected where the metal scope is large or the Owner's warranty on the system requires third-party records. {note}

+## Adhesion Testing {toc}

+### The adhesion testing requirement shall be as indicated in the datasheet.

+```datasheet

+label: Adhesion Testing of the Applied System

+type: select

+options:

+ - "Before overcoating every previously painted surface"

+ - "Only where the existing coating type is unknown or a shop primer's compatibility is unconfirmed"

+ - "No adhesion testing required"

+```

+### Adhesion shall be tested by ASTM D3359, by the cross-cut method for films thinner than 5 mils and the X-cut method for thicker films, on a test patch cured not less than seven days.

+### Adhesion tests shall be performed by the Contractor, and where a test fails, the retest after correction shall be at the Contractor's cost.

+### An adhesion test is the only field method that predicts whether a new film will stay on an old one, and it is cheap relative to the surface it qualifies. Testing every previously painted surface is selected on recoat projects where the existing films are many and undocumented; limiting it to unknown coatings and unconfirmed primers covers the two cases where compatibility is genuinely uncertain; waiving it suits new construction where every substrate is bare or carries an identified primer whose compatibility is confirmed in writing. {note}

+## Inspection Hold Points {toc}

+### The Contractor shall notify the Architect not less than 48 hours before each of the following stages on each substrate and shall not proceed past the stage until the Architect has inspected it or the notice period has expired without a response: completed surface preparation, completed primer, and completed finish.

+### Surface preparation and primer defects are invisible once the finish is on, and the hold points are the only moments at which they can be seen without destroying the finish to look. {note}

+# Delivery, Storage, and Handling {toc}

+## Coatings shall be delivered to the site in the manufacturer's original sealed containers, labeled with the product name, the MPI number where one applies, the color, the batch number, and the date of manufacture.

+## Materials shall be stored in a secure, ventilated space between 40°F and 95°F, or within the narrower range the manufacturer publishes, protected from freezing, direct sun, and open flame.

+## Waterborne material that has frozen shall not be used, and material that has exceeded the manufacturer's published shelf life shall be removed from the site.

+## Containers shall be kept closed except while material is drawn, and partly used containers shall be resealed to prevent skinning and contamination.

+## Mixing and storage areas shall be protected with drop cloths and spill containment, and spent solvent, rags, and surplus material shall be disposed of as the regulations in force at the project location require.

+## A waterborne coating that freezes breaks its emulsion and cannot be restored by thawing or stirring, and the damage is not visible in the can. Oily rags left in a pile can heat and ignite, which is why they are stored in a closed metal container. {note}

+# Warranty {toc}

+## The Contractor shall warrant the coating work against peeling, blistering, flaking, cracking, loss of adhesion, and chalking beyond the manufacturer's published rate, for not less than the period indicated in the datasheet from the date of Substantial Completion.

+```datasheet

+label: Contractor Warranty Period for the Coating Work

+type: range

+unit: yr

+min: 1

+max: 5

+setpoints: [1, 2, 3, 5]

+```

+## The Contractor's warranty shall cover the field-applied system, including its adhesion to the shop or factory primer the Contractor confirmed compatible, and shall not cover the shop or factory primer's adhesion to its own substrate, which remains under the warranty of the standard that governs that primer.

+## Where the manufacturer publishes a product or system warranty longer than the Contractor's period, the Contractor shall comply with the manufacturer's application and documentation conditions so that the Owner receives it, and the manufacturer's warranty shall apply in addition to the Contractor's.

+## A warranty repair shall restore the surface to match the adjacent work in color and sheen to the nearest natural break, and shall carry a fresh warranty of the original period from the date of the repair or the unexpired remainder of the original period, whichever ends later.

+## The Contractor shall bear the cost of removing, protecting, and reinstalling adjacent work disturbed by a warranty repair, and of repairing collateral damage the repair causes.

+## A one-year period matches the general correction period of most contracts and is what a project selects when the coating is one trade among many; two years carries the film through two full weather cycles, which is when preparation failures on exterior work appear; longer periods are selected on elastomeric and two-component systems whose manufacturers warrant the material for ten years and more, so that the workmanship warranty is not the shortest term on the wall. Normal weathering, fading and chalking within the manufacturer's published rate, and damage by others or by a moisture source behind the wall are outside the warranty. {note}

+# Extra Stock {toc}

+## The Contractor shall deliver to the Owner before final acceptance the quantity of each finish product, in each color and sheen used on the project, indicated in the datasheet, in sealed, labeled, original containers from the batches applied.

+```datasheet

+label: Extra Stock of Each Finish Product, Color, and Sheen

+type: range

+unit: gal

+min: 0

+max: 5

+step: 1

+default: 1

+```

+## Each container shall be labeled with the product, the MPI number where one applies, the color name and tint formula, the sheen, and the surfaces on which it was used, so that the Owner can match a touch-up without testing.

+## The Contractor shall obtain the Owner's signed receipt for the extra stock and shall include it in the closeout submittals.

+## Exterior touch-up is harder to blend than interior because the in-place film has weathered, and material from the same batch, with the formula recorded, is the closest match the Owner will ever get; a gallon of each color serves the first few years of touch-up on most buildings, and more is delivered where the Owner's maintenance staff will touch up rather than recoat. {note}

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