Spray Foam Roofing Calculator

Foam volume and coating from roof area and R-value target.

Roof Area (sqft)

Foam Thickness (inches)

Coating Type (0=Silicone, 1=Acrylic)

Walkway Area (sqft)

Waste Factor (%)

Tab to move between fields

Foam Required (board ft)

4,950

Foam Sets (A+B drums)9

Achieved R-Value9.8

Coating (gallons)99

Walkway Granules (lbs)150

Primer (gallons)11

Est. Material Cost ($)$10,470.00

How to Use This Calculator

Enter the roof area (sqft) and target foam thickness (inches).
Select coating type (silicone or acrylic) and enter walkway area (sqft).
Set waste factor (%).
Review board feet of foam needed, foam sets, achieved R-value, and gallons of coating.
Spray foam requires licensed applicators and favorable weather (low humidity, above 40F) for proper adhesion.

How the result changes with Roof Area (sqft)

Roof Area (sqft): Total roof surface area in square feet.
Foam Thickness (inches): Desired SPF thickness. 1-1.5" typical for re-roofing, 2-3" for new with insulation.
Coating Type (0=Silicone, 1=Acrylic): 0=Silicone (UV stable, ponding water OK), 1=Acrylic (cheaper, no ponding water).
Walkway Area (sqft): Area needing embedded granules for foot traffic protection.
Waste Factor (%): Extra material for overspray, detail work, and waste.

Foam Required (board ft): Total board feet of SPF (1 board foot = 1 sqft at 1 inch thick).
Foam Sets (A+B drums): Number of A+B component drum sets (~600 board feet per set).
Achieved R-Value: Thermal R-value from closed-cell SPF at R-6.5 per inch.
Coating (gallons): Gallons of protective elastomeric coating for all coats.
Walkway Granules (lbs): Granules embedded in coating for walkway protection.
Primer (gallons): Substrate primer for adhesion on metal or concrete.
Est. Material Cost ($): Approximate material cost (labor not included).

Identify Input Parameters
4 parameters
Roof Area (sqft) = 3000, Foam Thickness (inches) = 1.5, Coating Type (0=Silicone, 1=Acrylic) = 0, Walkway Area (sqft) = 200 = 5 input(s) provided
Calculate Foam Required
Foam Required = areaWithWaste * foamThicknessIn
4950 = 4950
Calculate Foam Sets
Foam Sets
9 = 9
Calculate Achieved R-Value
Achieved R-Value = foamThicknessIn * 6.5
9.8 = 9.8