What Is a Roofing Square?

A roofing square is the unit roofing is estimated and ordered in. One square covers 100 sq ft of roof, so a roof that measures 2,400 sq ft is 24 squares.

Surface, not floor area

The 100 sq ft is measured on the roof itself. A sloped roof is larger than the floor plan under it, and the steeper the slope, the larger the difference. The planner finds the surface area from a plan measurement and a pitch with a multiplier. Here is one 60 × 30 ft plan, 1,800 sq ft from above, at several pitches written as rise over a run of 12:

The flat case has a multiplier of 1, so the surface equals the plan. This works for one uniform pitch. Dormers, valleys and several pitches need each plane measured, or the measured surface area entered directly.

From squares to bundles

A square is a unit of area, not a count of anything you carry. Bundles come next, and they depend on the shingle. TAMKO’s rule of thumb is three bundles per square for most three-tab and laminated shingles, but a data sheet is the authority: TAMKO’s Heritage sheet lists a sales square as covering 98.4 sq ft when applied to its instructions, so the 100 sq ft square is the measuring convention and a product can describe its own coverage a little differently. A roofing square is a measurement; a shingle’s packaged coverage is a separate fact, so use the manufacturer’s coverage per bundle when you have it. The purchase math from area to whole bundles is its own page, because the coverage is yours to enter.

For the same idea on walls, see what a square of siding is, which uses the same 100 sq ft unit for a different material.