The squarish number “100” on the roof of a house refers to the number of bundles, or squares, on the roof. As a result, a square roof of roofing shingles covers 100 square feet of space. Some roofing materials are sold in smaller units than squares, and you’ll have to calculate your roof’s square footage based on that figure. The following information will help you figure out the square footage of your roof.

The number of shingles in a bundle varies, but in general, three bundles of shingles comprise one square. For example, a common three-tab bundle contains 29 shingles of standard size, which means that the square is 87 square feet in total. If you’re unsure, you can calculate your roof’s square footage by measuring the length of the building and then multiplying the two figures together.

A roofing square covers the surface area of a roof, and the number of bundles needed to complete a job is dependent on the roof’s slope and pitch. Professional roofers often purchase slightly more material than they actually need, so they can add on to the roof when necessary. Use the Roof Shingles Calculator to estimate the amount of squares you’ll need. This will help you ensure you’re getting enough material for your roof.

In the construction and roofing industry, the square is a handy unit for measuring the amount of shingles you’ll need. You can calculate this figure by multiplying the length of your roof by 100, and then dividing it by 1.3 for a low-incline roof. This way, you’ll know how many squares you’ll need for your entire roof. And if you’re trying to figure out how many squares you’ll need, you’re probably right.

Depending on how much roofing material you’ll need, you might want to get architectural or 3-tab shingles. These shingles contain multiple layers of asphalt, and will therefore weigh the same as an architectural bundle, but won’t have the same appearance. Both types of architectural shingles will usually cost you a little more than 3-Tap shingles. However, there are some exceptions to this rule. Some roofing shingles, such as GAF’s 3-tab shingles, require up to three bundles to cover a 100-square-foot roof.

A square roof should be at least two hundred square feet. For a 2400 square-foot roof, you’ll need 24 squares of underlayment. Underlayment can vary in composition, weight, and quality, so you’ll need to find one that fits your needs. Underlayment usually comes in rolls of 10 squares and #15 felt rolls have four squares each. This will give you enough material for the entire roof, but you’ll need to leave ten percent for trim and overlap.