How we worked it out
Updated as you change the numbers.
- Area = length × width = 20 ft × 8 ft = 160 sq ft.
- Board feet = area × 2 in.
Method and assumptions
Kits are rated at their theoretical yield; real yield is often 10 to 20% lower, especially in cold conditions, so buy extra. R-values per inch vary by product; check the data sheet.
Questions
How much spray foam for a 20 × 8 ft wall at 2 in?
320 board feet: one 600 board-foot kit, about R-13 with closed-cell foam.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.