11.4 Painting, Coatings, and Finish Schedules

Painting, Coatings, and Finish Schedules

The final Division 09 group covers surface preparation, coating systems, environmental limits, and the finish schedule that ties room finishes to the drawings. References include manufacturer data sheets, SSPC/NACE surface-prep standards for steel, ASTM D16 coating terminology, and OSHA 29 CFR 1926 Subpart Z (toxic and hazardous substances) plus Subpart D (lead in construction).

Surface preparation

Coating performance is mostly about prep. For steel, SSPC standards define the cleanliness:

• SSPC-SP1: solvent cleaning (remove oil/grease) — always first.
• SSPC-SP2/SP3: hand/power tool cleaning.
• SSPC-SP6: commercial blast.
• SSPC-SP10: near-white blast (immersion service).

For gypsum board, prime before topcoat so the porous paper and the harder joint compound do not flash (show as dull/glossy patches). New concrete and masonry must cure and have pH below about 10 before alkali-sensitive coatings.

Coating systems and spread rate

A typical system is primer + two finish coats. Estimate paint using the theoretical coverage (often 350 to 400 square feet per gallon) divided by a loss factor:

• Wall area: 1,600 square feet.
• Coverage: 350 sq ft per gallon.
• Coats: 2.
• Gallons = (1,600 / 350) x 2 = 9.14, order 10 gallons.

Rough or porous surfaces lower coverage; spray application adds overspray loss. Dry film thickness (DFT) is verified with a gauge against the spec — too thin fails early, too thick can crack.

Environmental limits and VOCs

Manufacturers set application windows. Typical limits:

• Air/surface temperature: about 50 to 90 degrees Fahrenheit for latex (read the data sheet).
• Surface temperature: at least 5 degrees Fahrenheit above the dew point to prevent condensation.
• Humidity: generally below 85 percent.

Volatile Organic Compound (VOC) content is limited by EPA and many state/local rules; flat interior latex is often capped near 50 to 100 grams per liter. Low-VOC products help meet LEED indoor air quality credits.

OSHA lead and hazard rules (29 CFR 1926.62, Subpart Z)

Disturbing old coatings can release lead. Key triggers:

• Permissible Exposure Limit (PEL): 50 micrograms per cubic meter (8-hour TWA).
• Action Level: 30 micrograms per cubic meter, triggering exposure monitoring.
• Provide respirators, training, and hygiene facilities when above the action level.

Solvents and coatings also fall under Hazard Communication (29 CFR 1910.1200 / 1926.59) — maintain Safety Data Sheets (SDS) on site and label containers. Confined-space coating requires ventilation per Subpart D/E.

The finish schedule and markup math

The finish schedule is a drawing table listing each room and its floor, base, wall, and ceiling finishes plus paint codes. It coordinates Divisions 09 finishes and resolves conflicts between the specification and the plans.

For bidding, distinguish markup from margin. If painting cost is 8,000 dollars and you want a 20 percent margin, divide by (1 - 0.20): 8,000 / 0.80 = 10,000 dollars price. A 20 percent markup instead would be 8,000 x 1.20 = 9,600 dollars — a frequent exam trap; margin always yields a higher price than the same-percentage markup.

Surface Prep and Coating Systems

Paint adhesion is 90% surface prep: clean, dry, sound, and properly profiled. A coating system is primer + topcoat(s); primer seals/bonds (use the right primer — stain-blocking for tannin/smoke, bonding for glossy substrates, galvanized metal primer for galv steel). Bare metal needs a rust-inhibitive primer; new drywall needs a PVA primer to equalize porosity. Recoat within the product's window and respect dew point/temperature limits (most paints fail below ~50°F).

Sheen, Coverage, and a Worked Takeoff

Sheen runs flat → eggshell → satin → semi-gloss → gloss; higher sheen is more washable/durable (kitchens, trim) but shows surface defects more. Coverage ~350–400 SF/gallon per coat on smooth surface (less on rough/porous). Worked example: 1,600 SF of wall, 2 coats, at 350 SF/gal = (1,600 × 2)/350 = 9.1 → order 10 gallons plus primer. Rough block can drop to 150 SF/gal.

Finish Schedules and VOC Rules

The finish schedule (a Division 09 document) lists each room's floor, base, walls, and ceiling finish by code, keyed to the spec — the painter and other finish trades work from it. VOC limits (EPA/state, e.g., CARB/SCAQMD) cap solvent content; LEED projects require low-VOC paints, adhesives, and sealants. Lead-based paint (pre-1978) triggers EPA RRP lead-safe work practices on renovation.

Common Exam Traps

• Trap: Painting over a dirty/glossy surface without prep/bonding primer (peels).
• Trap: Using flat paint in a wet/high-traffic area (use washable semi-gloss).
• Trap: Ignoring temperature/dew point limits when painting.
• Trap: Disturbing pre-1978 paint without RRP lead-safe practices.

Application Methods and Mil Thickness

Apply by brush, roller, or spray; spraying is fast but needs masking and often back-rolling to work coating into the surface. Specs state a target dry film thickness (DFT in mils) verified with a gauge — spreading one gallon too thin to save material leaves an under-thickness film that fails early, while too thick a coat runs or traps solvent. Recoat windows matter: recoating outside the manufacturer's window can cause intercoat adhesion failure (lifting/wrinkling). Match the system, film build, and cure to the substrate and exposure.

Specialty Coatings and Sequencing

Beyond architectural paint, finishes include epoxy floor coatings (durable chemical-resistant systems needing a profiled, moisture-tested slab), intumescent fireproofing that swells under heat to protect steel, and elastomeric coatings that bridge hairline masonry cracks. Sequence painting in the finish schedule order: prime before other trades dirty the walls, then final coat after ceilings, flooring underlayment, and trim so the painter is not chasing damage. Protecting completed finishes until closeout is part of the painter's scope.