1 Scope
NOTE This standard governs surface preparation, priming, and finish coating of exposed exterior architectural substrates in commercial and institutional construction. (1.1)
1.2The 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.
NOTE 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. (1.3)
1.4The Contractor shall treat the work as a coating system, not a sequence of coats.
1.5The 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.
NOTE 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. (1.6)
1.8Where 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.
2 Referenced Standards
2.1All materials, surface preparation, and application shall comply with the latest edition adopted by the Authority Having Jurisdiction for each of the following standards.
2.2 Referenced Standards List
| 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) |
NOTE 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. (2.2.1)
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. (2.2.2)
2.3 Compliance Hierarchy
2.3.1Where 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.
NOTE 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. (2.3.2)
3 Submittals
3.1 Action Submittals
3.1.1The 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
☐ 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
3.1.2Application 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.
3.2 Closeout Submittals
3.2.1The 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
☐ Final coating schedule of applied products, colors, formulas, gloss, and DFT
☐ Manufacturer warranty documentation
☐ Maintenance and recoat instructions
4 Quality Assurance
4.1 Applicator Qualifications
NOTE 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. (4.1.1)
4.1.2Exterior 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.
4.1.3The applicator shall be acceptable to the coating manufacturer for application of the specified high-performance systems.
4.2 Manufacturer's Approved Products
NOTE Specifying by MPI number lets the Contractor select from competing approved products while guaranteeing the minimum performance the system requires. (4.2.1)
○ Yes — all products shall be MPI-listed for the assigned MPI product number
○ No — products to meet performance described, MPI listing not mandatory
4.2.2Each coating product shall meet the performance of the MPI product number assigned to its position in the coating system.
4.2.3Where the contract documents require MPI-listed products, each product shall appear on the current MPI Approved Products List for that MPI number.
4.3 Single Manufacturer per System
NOTE 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. (4.3.1)
○ Single manufacturer for primer through finish of each system
○ Primer and finish from different manufacturers — manufacturer-confirmed compatibility required
4.3.2All coats within a single coating system — primer, intermediate, and finish — shall be furnished by one manufacturer.
4.3.3All coats within a single coating system shall be confirmed by that manufacturer as compatible for use together over the specified substrate and surface preparation.
4.4 Field Mock-Up
○ Yes — one mock-up per major substrate and coating system
○ No
4.4.1Where 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.
4.4.2The 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.
4.4.3The 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.
5 Environmental and Service Conditions
5.1 Service Environment Classification
NOTE 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. (5.1.1)
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
5.1.2The 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.
5.2 Temperature Limits During Application
NOTE Most conventional waterborne coatings require a minimum of 50 °F (10 °C); some low-temperature-cure formulations are rated to 35 °F (2 °C). (5.2.1)
5.2.2Below 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.
NOTE Above the maximum, solvent or water flashes off too rapidly, causing dry spray, lap marks, and poor wet edge. (5.2.3)
5.2.4Coatings 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.
5.2.5These temperature limits shall be maintained throughout the application and the initial cure period.
5.3 Dew Point and Substrate Moisture
NOTE 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. (5.3.1)
5.3.2Coatings 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.
5.3.3Application shall stop if conditions change such that condensation forms during application or before the film has cured.
5.3.4The 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.
5.4 Wind, Rain, and Drying Window
5.4.1Coatings 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.
5.4.2Exterior 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.
5.4.3The Contractor shall confirm the local weather forecast before beginning each day's exterior coating.
5.4.4The Contractor shall not apply a coat that cannot achieve its minimum dry-to-rain time before the next precipitation event.
6 Coating Systems by Substrate
6.1 Concrete and Cementitious Substrates
NOTE 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. (6.1.1)
6.1.2The 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.
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)
6.1.3The coating selected for concrete and cementitious substrates shall match the MPI EXT system number for the substrate and the chosen performance.
6.2 Block Filler for Concrete Masonry
NOTE 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. (6.2.1)
○ Required — high-build block filler before primer/finish
○ Not required — masonry is factory-prefilled or substrate is not CMU
6.2.2Exposed concrete masonry shall receive a block filler before the primer and finish coats unless the masonry has been factory-prefilled.
6.2.3Block filler shall be applied to fill the surface voids completely and provide a uniform base for the finish system.
NOTE 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. (6.3.1)
NOTE Incompatible field coats over an unknown shop primer is a frequent cause of lifting and delamination. (6.3.2)
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)
6.3.3Exposed ferrous metal scheduled to be field-painted shall receive a corrosion-inhibiting primer followed by finish coats appropriate to the service environment.
6.3.4Where the steel was shop-primed under 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. NOTE 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. (6.4.1)
○ Waterborne bonding primer formulated for galvanized / non-ferrous
○ Acrylic direct-to-metal listed for galvanized
○ Not applicable — no galvanized or non-ferrous metal scheduled
6.4.2Galvanized 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.
6.4.3Oil-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.
6.5 Exterior Wood
NOTE Exterior wood expands and contracts with moisture; a brittle, high-gloss film over dimensionally active wood cracks and peels. (6.5.1)
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
6.5.2Exterior 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.
6.5.3Knots and resinous areas shall receive a stain-blocking spot primer to prevent bleed-through.
6.5.4Finish coats on exterior wood shall remain flexible.
6.6 Previously-Painted Surfaces
NOTE Recoating over a failing or incompatible existing film simply transfers the failure to the new coating. (6.6.1)
Spot-repair — remove failed areas, clean and dull sound coating, recoat
Full removal to substrate — existing coating unsound or incompatible
Not applicable — new substrate
6.6.2Previously-painted exterior surfaces scheduled for recoating shall be assessed for the soundness and the adhesion of the existing coating before recoating.
6.6.3All loose, peeling, blistered, and chalking coating shall be removed.
6.6.4The remaining sound coating shall be cleaned and dulled to provide a mechanical key.
6.6.5The 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.
7 Surface Preparation by Substrate
7.1 General Surface Preparation Requirements
NOTE Surface preparation is the single most important determinant of exterior coating performance. (7.1.1)
7.1.2Surface preparation shall be completed and accepted before any primer is applied.
7.1.3All 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.
7.1.4The preparation grade for each substrate shall be as specified below and shall conform to the cited SSPC-SP or ASTM standard.
NOTE 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. (7.2.1)
7.2.2All 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.
NOTE 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. (7.3.1)
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. (7.3.2)
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)
7.3.3The preparation grade for exposed ferrous metal shall be selected to match the coating system and the service environment.
7.4 Concrete and Masonry Preparation
NOTE Coating applied over efflorescence is pushed off the wall as the salts continue to migrate and crystallize beneath the film. (7.4.1)
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)
7.4.2Concrete, 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.
7.4.3Where 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.
7.4.4Efflorescence shall be removed and its source addressed.
7.5 Concrete Cure Before Coating
NOTE Coating applied to green, high-moisture, high-alkalinity concrete blisters, delaminates, and suffers alkali attack on the binder. (7.5.1)
7.5.2New 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.
7.5.3A 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.
7.6 Galvanized and Non-Ferrous Preparation
7.6.1Weathered 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.
7.6.2After 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.
7.7 Mildew Removal
NOTE Coating over live mildew is a recurring exterior failure in shaded, humid, and north-facing locations. (7.7.1)
○ Required — mildewcide added to finish coats (shaded, humid, or mildew-prone exposure)
○ Not required — manufacturer's standard formulation
7.7.2Surfaces 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.
7.7.3Mildew shall be killed and removed by washing, and the dead mildew and its staining shall be removed from the surface before priming.
8 Number of Coats and Dry Film Thickness
8.1 Number of Coats
NOTE 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. (8.1.1)
1 finish coat
2 finish coats (standard)
3 finish coats (deep colors, porous substrates, high-build systems)
8.1.2Each 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.
8.1.3In no case shall a coating system over a previously uncoated substrate consist of fewer than one primer coat and two finish coats.
8.2 Total System Dry Film Thickness
NOTE 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. (8.2.1)
8.2.2The total system dry film thickness shall meet the minimum specified for the coating system and shall be verified in the field.
8.2.3The specified dry film thickness shall fall within the manufacturer's recommended range for the product and the number of coats.
9 Gloss and Sheen
9.1 Gloss Level
NOTE 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. (9.1.1)
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. (9.1.2)
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)
9.1.3The 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.
10 Volatile Organic Compound Content
10.1 VOC Compliance
10.1.1SCAQMD 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.
10.1.2Alkyd (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.
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
10.1.3All coatings shall comply with the VOC content limits in force at the project location.
10.1.4The 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.
10.1.5The Contractor shall confirm the VOC limits for the specific project location.
11 Color
11.1 Color Selection
11.1.1Deep 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.
○ Custom — per exterior color schedule, confirmed by approved drawdown
○ Manufacturer standard color — selected from available range
11.1.3Custom and deep-tint colors shall be confirmed by an approved drawdown sample before bulk material is tinted and ordered.
11.1.4Where a coating is supplied in a limited factory color range, the specified color shall be confirmed against the available range during submittal review.
12 Field Testing
12.1 Dry Film Thickness Verification
NOTE 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. (12.1.1)
○ Required on metal substrates per SSPC-PA 2
○ Required on all substrates (metal per SSPC-PA 2; others per manufacturer method)
12.1.2The 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.
12.1.3Dry 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.
12.2 Adhesion Testing
NOTE 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. (12.2.1)
○ Required — over existing coatings of unknown type and where specified
○ Not required
12.2.2Where 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.
12.3 Concrete Moisture Testing
NOTE 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. (12.3.1)
○ Required — ASTM D4263 plastic sheet method (or manufacturer-approved meter)
○ Not required — substrate is not cementitious
12.3.2Before 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.
12.3.3Coating shall not be applied until the moisture condition is within the coating manufacturer's stated limit.
13 Application
13.1 Application Methods
NOTE Spray alone bridges the surface texture and leaves voids and pinholes that compromise weather resistance. (13.1.1)
Brush and roller
Spray, back-rolled into porous substrates
Spray only (smooth substrates, non-porous metal)
Per manufacturer's data sheet for each product
13.1.2Coatings 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.
13.1.3Spray 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.
13.1.4The 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.
13.2 Recoat Times
13.2.1Recoating 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.
13.2.2Each 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.
13.2.3The 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.
13.3.1The 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.
13.3.2The Contractor shall maintain a wet edge during application to avoid lap marks.
13.3.3The Contractor shall complete each continuous surface in one operation where possible so that no visible joint occurs in the field of a wall.
14 Delivery, Storage, and Handling
NOTE Waterborne coatings are permanently ruined by freezing — the emulsion breaks and cannot be reconstituted. (14.1)
14.2 Storage Temperature
14.2.1Coatings shall be delivered to the project in the manufacturer's original sealed containers with labels and batch numbers intact and legible.
14.2.2Materials shall be stored in a clean, dry, secure location protected from freezing, from temperatures above the manufacturer's storage maximum, and from direct sunlight.
14.2.3Waterborne coatings shall be protected from freezing throughout storage and transport.
14.2.4Containers shall be kept closed except when material is being drawn, and partially used containers shall be resealed to prevent skinning and contamination.
14.2.5Material exceeding the manufacturer's shelf life shall not be used.
15 Warranty
15.1 Manufacturer's Warranty
NOTE 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. (15.1.1)
15.1.2Coating products shall be warranted by the manufacturer against defects in materials for the period stated in the manufacturer's published warranty.
15.1.3The Contractor shall comply with the manufacturer's conditions so that the Owner receives the full benefit of the warranty.
15.2 Applicator's Warranty
NOTE Normal weathering, fading, and chalking within the coating's published performance, and damage from causes outside the Contractor's control, are not workmanship defects. (15.2.1)
1 year from substantial completion
2 years from substantial completion
5 years from substantial completion (high-performance systems)
15.2.2The 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.
16 Spare and Extra Materials
16.1Exterior 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.
16.2.1The 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.
16.2.2Each 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.