Exterior paint coverage varies by surface: 350-400 sq ft/gal for smooth siding, 250-300 sq ft/gal for textured surfaces, and 200-300 sq ft/gal for rough stucco or brick. Primers cover 200-300 sq ft/gal regardless of surface type.
🎨 Coverage by Surface Type
| Surface Type | Paint (sq ft/gal) | Primer (sq ft/gal) | Notes |
|---|---|---|---|
| Smooth Vinyl Siding | 350-400 | 200-300 | Best coverage, minimal absorption |
| Fiber Cement Siding (Smooth) | 350-400 | 200-300 | Similar to vinyl when sealed |
| Wood Siding (New) | 300-350 | 200-300 | Smooth wood, pre-sealed |
| Wood Siding (Weathered) | 250-300 | 200-300 | Higher absorption, needs more coats |
| Textured Surfaces | 250-300 | 200-300 | Rough sawn wood, textured fiber cement |
| Rough Stucco | 200-300 | 200-300 | Heavy texture increases paint usage |
| Brick (Unsealed) | 200-300 | 200-300 | Very porous, requires multiple coats |
Key Takeaway
Primers universally cover 200-300 sq ft per gallon regardless of surface type. This reduced coverage ensures proper sealing and adhesion. Paint coverage varies by surface texture and porosity.
🔧 Application Method & Waste Factors
Brush & Roller
Airless Sprayer
Conventional Air Spray
HVLP Sprayer
🧮 Example Calculation
Two-Story House with Wood Siding
Step 1: Calculate wall area
Perimeter: 150 feet
Average height: 20 feet (two stories)
Total: 150 × 20 = 3,000 sq ft
Step 2: Deduct openings
Doors & windows: ~400 sq ft
Paintable area: 3,000 - 400 = 2,600 sq ft
Step 3: Calculate primer needed
Coverage: 250 sq ft/gal (mid-range for primer)
Primer: 2,600 ÷ 250 = 10.4 gallons
With 10% waste: 10.4 × 1.10 = 11.5 → 12 gallons
Step 4: Calculate paint needed (2 coats)
Coverage: 275 sq ft/gal (weathered wood)
Per coat: 2,600 ÷ 275 = 9.5 gallons
Two coats: 9.5 × 2 = 19 gallons
With 10% waste: 19 × 1.10 = 20.9 → 21 gallons
Total Materials:
• Primer: 12 gallons
• Paint: 21 gallons (2 coats)
📚 Industry Standards
PCA Standards (formerly PDCA)
The Painting Contractors Association provides guidelines for exterior paint coverage rates, surface preparation requirements, and quality standards. Standard coverage: 350-400 sq ft/gal for smooth surfaces.
ASTM D3274 - Evaluating Degree of Surface Disfigurement
Standard guide for assessing chalking of exterior paint films. Determines when repainting is necessary based on surface degradation.
ASTM D6577 - Measuring Wet Film Thickness
Standard for determining proper paint application thickness. Ensures adequate coverage and durability for exterior surfaces.
Surface Preparation Standards
SSPC (Society for Protective Coatings) standards specify proper cleaning, scraping, sanding, and priming procedures for various exterior surfaces. Proper prep is critical for paint adhesion and longevity.
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