A board foot of spray foam is a volume measurement: one square foot of foam, one inch thick (1 ft x 1 ft x 1 in). To find board feet, multiply the square footage of the area by the number of inches of foam. So 1,000 square feet of wall sprayed 3 inches thick is 3,000 board feet. Spray foam contractors use board feet because foam is sold, sprayed, and tracked by volume. Once you understand the unit, a spray foam quote becomes much easier to read and compare. Why Spray Foam Use

Spray foam insulation cost depends mostly on the type of foam (open-cell or closed-cell), how thick it's applied, how many square feet are covered, how easy the area is to reach, and how much prep and cleanup the job needs. Because those factors vary so much from one building to the next, the only way to know your real cost is an on-site estimate. What you can do ahead of time is understand what goes into the number, so you can compare quotes fairly. Spray foam is usually pri