Roofing Squares and Shingle Bundles

Understand the purchasing units of roofing: the square, the bundle and the coverage figure that ties them together.

Roofing is ordered in squares and bundles, and getting those units right is half the battle. A roofing square is 100 square feet of roof surface. A bundle is a package of shingles, and its coverage is how many square feet one bundle installs at the correct exposure.

The 100 square foot definition

Because a square is exactly 100 sq ft, converting area to squares is just dividing by 100. A 1,500 sq ft roof is 15 squares before waste. Squares make it easy to talk about quantity with suppliers, but you still buy bundles, so you need the coverage figure.

Bundles per square depend on the product

A common figure is three bundles per square for lighter shingles that cover about 33⅓ sq ft each. But four or even five bundles per square are normal for heavier architectural or designer shingles. Treat three, four or five bundles per square as product-dependent examples, never universal defaults, and read the number printed on the wrapper.

Round at the right moment

Compute the order area first by applying your waste allowance to the net area, then divide by the bundle coverage and round up to whole bundles. Rounding before you apply waste, or rounding squares instead of bundles, can leave you a bundle short or with a wasted bundle. The shingle calculator follows this order automatically.