Spray Foam Calculator
Calculates two-component polyurethane spray foam insulation kits (such as Touch 'n Seal or DuPont Froth-Pak 200 and 600 kits) in board feet (1 bd ft = 1 sq ft at 1 inch thick) for rim joists, crawlspaces, metal buildings, and wall cavities.
Formula
Board Feet (bd ft) = (Sq Ft × Thickness in) × (1 + Waste %); Kits (Froth-Pak 600) = Ceil(bd ft ÷ 600)
1. Board Feet = Square Feet × Thickness in Inches 2. Gross Board Feet with Waste = Board Feet × (1 + Waste %) 3. Froth-Pak 600 Kits (yields 600 bd ft) = Ceil(Gross bd ft ÷ 600) 4. Froth-Pak 200 Kits (yields 200 bd ft) = Ceil(Gross bd ft ÷ 200) 5. R-Value Achieved = Thickness in × (Closed Cell: 7.0 / Open Cell: 3.8)
Inputs
- Surface Area to Insulate
- Applied Foam Thickness
- Spray Foam Chemistry
Worked example
Insulating and air-sealing a basement rim joist perimeter (300 sq ft) with 2 inches of closed-cell foam (R-14).
Outcome: 300 sq ft × 2 inches = 600 board feet. With 15% overspray allowance, total volume is 690 board feet. Requires one Froth-Pak 600 kit plus one Froth-Pak 200 kit (800 bd ft total). Achieves R-14 and creates an impermeable vapor barrier.
Why does spray foam kit temperature matter so critically during application?
The A and B chemical cylinders must be warmed to 75°F–85°F prior to spraying. If the tanks are cold (below 65°F), the chemicals will not mix in the correct 1:1 ratio, resulting in sticky unreacted foam that fails to cure or off-gasses odors.