Estimating Materials Using Square Feet
To estimate materials divide the total square footage by the coverage of the product. For example, to estimate plywood for subfloor, divide the total square footage by 32 (the square feet in a 4′ by 8′ sheet). If the total floor area is 1,440 square feet:
Insulation required for the same floor area given that each insulation package covers 47 square feet:
1,440/47 = 30.63 PACKAGES (SELL 31)
Always round up to the next highest selling unit.
For product sold by the square (vinyl siding) divide the total square footage by 100 (a square is 100 square feet).