Insulation for an area
Enter area to cover and the coverage printed on the package. 5 percent added.
sq ft
sq ft
m²
m²
Area with waste
-sq ft
Packages
-
packages = (area × 1.05) ÷ coverage per package
Area with waste
-m²
Packages
-
packages = (area × 1.05) ÷ coverage per package
Estimate only. Includes 5 percent. Confirm the final quantity with your supplier before ordering.
How the insulation estimate works
Insulation is sold by area coverage, which depends on the product and its R value or thickness. Read the coverage printed on the bag or roll, then divide your area by it. Higher R value batts of the same width cover the same floor area but are thicker, so coverage is about area, not R value. Add about 5 percent for trimming and offcuts.
Cutting batts? A sharp retractable utility knife with spare blades makes clean cuts through fibreglass and mineral wool.
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Common questions
How much insulation do I need for 500 square feet?
With 5 percent waste that is 525 square feet. If each package covers 40 square feet, you need 14 packages.
Does R value change how much I buy?
Not the number of packages for a given floor area. R value sets the thickness and price, while coverage per package tells you how many to buy.
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