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

R-value measures how well a material resists heat flowing through it, and higher numbers mean better resistance. Closed-cell spray foam is roughly R-6 to R-7 per inch, while open-cell spray foam is roughly R-3.5 to R-3.8 per inch. But R-value only tells part of the story, because it doesn't measure air leakage, and air leakage is where many Iowa homes lose the most heat. When you're comparing insulation quotes or reading product labels, it helps to know what the number does a