Exterior Painting and Coatings
Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
Showing changes from Rev 6
to Rev 7
in Exterior Painting and Coatings.
---
title: Exterior Painting and Coatings
…102 unchanged lines
- 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]
+default:
+ - "Final coating schedule of applied products, colors, formulas, gloss, and DFT"
+ - "Manufacturer warranty documentation"
+ - "Maintenance and recoat instructions"
```
…12 unchanged lines
### 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
…5 unchanged lines
```
−### Each coating product shall meet the performance of the MPI product number assigned to its position in the coating system.
−
−### Where the contract documents require MPI-listed products, each product shall appear on the current MPI Approved Products List for that MPI number.
−
## Single Manufacturer per System {toc}
### Mixing primers and finishes from different manufacturers transfers the risk of intercoat adhesion failure to the Contractor and voids the system warranty; the manufacturer will not warrant a film it did not formulate as a system. {note}
+### All coats within a single coating system — primer, intermediate, and finish — shall be furnished by one manufacturer.
+
```datasheet
label: Coating System Sourcing
…5 unchanged lines
```
−### All coats within a single coating system — primer, intermediate, and finish — shall be furnished by one manufacturer.
−
### All coats within a single coating system shall be confirmed by that manufacturer as compatible for use together over the specified substrate and surface preparation.
…32 unchanged lines
### 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
…8 unchanged lines
```
−### The coating system shall be selected for the service environment to which the building is exposed, because the environment governs which generic resin will retain color, gloss, and film integrity over the design service life.
−
## Temperature Limits During Application {toc}
…2 unchanged lines
### 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
…7 unchanged lines
```
−### Coatings shall not be applied when the ambient air temperature or the substrate surface temperature is below the minimum or above the maximum stated on the manufacturer's technical data sheet.
−
### These temperature limits shall be maintained throughout the application and the initial cure period.
…2 unchanged lines
### 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
…7 unchanged lines
```
−### Coatings shall not be applied unless the substrate surface temperature is at least 5 °F (3 °C) above the measured dew point and the surface is dry.
−
### Application shall stop if conditions change such that condensation forms during application or before the film has cured.
…35 unchanged lines
### 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
…6 unchanged lines
```
−### Exposed concrete masonry shall receive a block filler before the primer and finish coats unless the masonry has been factory-prefilled.
−
### Block filler shall be applied to fill the surface voids completely and provide a uniform base for the finish system.
…3 unchanged lines
### 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
…8 unchanged lines
```
−### Exposed ferrous metal scheduled to be field-painted shall receive a corrosion-inhibiting primer followed by finish coats appropriate to the service environment.
−
### Where the steel was shop-primed under [[sync/structural-steel-framing]], the field system shall be compatible with the shop primer, and the Contractor shall confirm compatibility or apply a tie-coat before finishing.
…2 unchanged lines
### 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
…7 unchanged lines
```
−### Galvanized steel, aluminum, and other non-ferrous metals scheduled to be field-painted shall receive a primer specifically formulated for the metal, applied after solvent cleaning and any required passivation or etch.
−
### Oil-based and alkyd primers shall not be applied directly to galvanized steel, because the zinc surface saponifies the alkyd binder and the coating fails by peeling.
…2 unchanged lines
### 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
…8 unchanged lines
```
−### Exterior wood scheduled to be coated shall receive a primer suited to the finish — an alkali-resistant, stain-blocking primer for opaque (paint) finishes, or a penetrating finish for transparent and semi-transparent finishes — followed by the specified topcoats.
−
### Knots and resinous areas shall receive a stain-blocking spot primer to prevent bleed-through.
…4 unchanged lines
### 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
…7 unchanged lines
```
−### Previously-painted exterior surfaces scheduled for recoating shall be assessed for the soundness and the adhesion of the existing coating before recoating.
−
### All loose, peeling, blistered, and chalking coating shall be removed.
…25 unchanged lines
### 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
…8 unchanged lines
```
−### The preparation grade for exposed ferrous metal shall be selected to match the coating system and the service environment.
−
## Concrete and Masonry Preparation {toc}
### Coating applied over efflorescence is pushed off the wall as the salts continue to migrate and crystallize beneath the film. {note}
+### 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
…7 unchanged lines
```
−### Concrete, masonry, and stucco shall be prepared in accordance with SSPC-SP 13 / NACE No. 6 and cleaned in accordance with ASTM D4258, removing laitance, form-release agents, efflorescence, curing compounds, dust, and any unsound material.
−
### Where the surface profile is too smooth or too contaminated to clean adequately, the surface shall be abraded in accordance with ASTM D4259 to expose a sound, slightly textured surface that the coating can key into.
…4 unchanged lines
### 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
…7 unchanged lines
```
−### New concrete and masonry shall be allowed to cure before coating so that excess moisture and surface alkalinity have subsided to levels the coating can tolerate.
−
−### A minimum cure of 28 days is the conventional requirement for film-forming coatings on new concrete unless the coating manufacturer's technical data sheet and a moisture test establish that a shorter interval is acceptable.
−
## Galvanized and Non-Ferrous Preparation {toc}
…6 unchanged lines
### 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
…16 unchanged lines
### 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
…7 unchanged lines
```
−### Each coating system shall consist of a primer plus the number of finish coats required to achieve the specified total dry film thickness, complete hide, and uniform appearance.
−
### In no case shall a coating system over a previously uncoated substrate consist of fewer than one primer coat and two finish coats.
…2 unchanged lines
### 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
…7 unchanged lines
```
−### The total system dry film thickness shall meet the minimum specified for the coating system and shall be verified in the field.
−
### The specified dry film thickness shall fall within the manufacturer's recommended range for the product and the number of coats.
…5 unchanged lines
### 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)
…11 unchanged lines
```
−### The gloss level of the finish coat shall be as specified for each surface, expressed by the MPI gloss level designation (G1 through G7), which defines the gloss measured at 60 degrees and the sheen measured at 85 degrees.
−
# Volatile Organic Compound Content {toc}
…47 unchanged lines
### 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
…5 unchanged lines
```
−### The Contractor shall verify the dry film thickness of coatings applied to metal substrates in accordance with SSPC-PA 2, using a Type 1 (magnetic pull-off) or Type 2 (electronic) gauge, and shall record the spot and area measurements.
−
### Dry film thickness on non-ferrous and non-metallic substrates shall be verified by the manufacturer's recommended method, including wet-film gauge readings during application correlated to the target dry film thickness.
…2 unchanged lines
### 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)
…6 unchanged lines
```
−### Where adhesion verification is specified, or where a coating is applied over an existing coating of unknown type, adhesion shall be verified by the tape test in accordance with ASTM D3359.
−
## Concrete Moisture Testing {toc}
### The ASTM D4263 plastic sheet method is a simple field screen in which a plastic sheet is taped to the surface and inspected for condensation after a set interval; condensation indicates capillary moisture migrating from within the concrete that will blister or delaminate the coating. {note}
+### 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
…5 unchanged lines
```
−### Before coating concrete and masonry, the Contractor shall confirm acceptable surface moisture in accordance with ASTM D4263 (plastic sheet method), or by an electronic moisture meter or other method acceptable to the coating manufacturer.
−
### Coating shall not be applied until the moisture condition is within the coating manufacturer's stated limit.
−# Application {toc}
+# Application Methods {toc}
−## Application Methods {toc}
+## Spray alone bridges the surface texture and leaves voids and pinholes that compromise weather resistance. {note}
−### 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
…8 unchanged lines
```
−### Coatings shall be applied by brush, roller, or spray as appropriate to the product, the substrate, and the required appearance, and as permitted by the manufacturer's technical data sheet for the product.
+## Spray application of exterior coatings shall be back-rolled or back-brushed where required to work the coating into porous substrates such as masonry and rough concrete.
−### Spray 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.
−### 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}
−## 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.
−### 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.
−### 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.
−### 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}
−## 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 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 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.
−### 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}
…38 unchanged lines
### 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
…6 unchanged lines
```
−### The Contractor shall warrant the coating application against defective workmanship — including peeling, blistering, flaking, excessive chalking beyond the coating's published rate, and premature loss of adhesion attributable to inadequate surface preparation or improper application — for the project warranty period.
−
# Spare and Extra Materials {toc}
…16 unchanged lines
### 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.