What Is a Roofing Square?
A roofing square is a standard unit used to describe roof area. One roofing square equals 100 square feet of roof surface. For example, a roof with 2,000 square feet of actual surface area contains 20 roofing squares.
Roofing squares are commonly used when estimating materials such as asphalt shingles. The number of bundles needed for each square depends on the specific shingle product, so always use the manufacturer's coverage information.
Why Roof Pitch Changes the Amount of Roofing You Need
The footprint of a building is not the same as the actual surface area of a sloped roof. As roof pitch increases, the distance from the ridge to the eave becomes longer, increasing the total area that must be covered.
This is why simply multiplying the length and width of a building can underestimate roofing material. The roof's slope must also be considered unless you already know the actual measured roof surface area.
What Is Roofing Waste?
Roofing materials usually cannot be installed with zero waste. Shingles, panels, and other materials may need to be cut around roof edges, valleys, hips, dormers, vents, chimneys, and other features.
A simple roof may produce relatively little waste, while a complicated roof with many angles and intersections can produce considerably more. Extra material can also be useful for replacing damaged pieces or making future repairs.
Measuring Complex Roofs
A complicated roof can often be easier to estimate by dividing it into several simpler sections. Each section can be measured separately and the resulting roof areas added together.
Gables, additions, porches, dormers, and roofs with different slopes may be treated as separate sections. For highly irregular roofs, measurements from a roofing plan or professional roof measurement may provide a more reliable estimate.