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Roofingaka: squareaka: 100 SF

Roofing Square

In Plain English

The roofing industry's unit of measurement — one square equals 100 square feet of roof surface.

Definition

A unit of measure equal to 100 square feet of roof surface area, used to quantify roofing materials and labor. Roofing material quantities (shingles, felt, membrane) are calculated and sold by the square. A 2,000 square foot house with a simple gable roof typically has about 22 squares of actual roof surface due to the slope.

Why It Matters in Bidding

The square is the universal pricing unit on roofing bids, so subs quote labor and material per square and estimators must convert plan dimensions and slope into squares accurately. Failing to add a waste factor for hips, valleys, and starter/cap shingles, or ignoring the slope multiplier, produces a takeoff that comes up short once the crew is on the roof.

Example

A roofing estimator measures 2,000 square feet of building footprint, applies a 1.12 slope multiplier and a 10% waste factor for cuts, and bids 24.6 squares of architectural shingles plus underlayment.

Related Terms

ShinglePitchCap SheetBuilt-Up Roof (BUR)

Frequently Asked Questions

Divide the actual sloped roof area by 100. The trick is computing the true sloped area, not the flat footprint, by applying a pitch multiplier. Then add waste for hips, valleys, and trim. Skipping the slope conversion is the single most common reason a roofing takeoff falls short of field needs.
The footprint is flat, but the roof is pitched, so the surface area is larger than the floor area below it. A steeper pitch increases the multiplier. Overhangs, dormers, and complex geometry add more area, which is why actual squares routinely exceed the simple footprint-divided-by-100 number.
It varies by complexity. Simple gable roofs may run around 10%, while roofs with many hips, valleys, and penetrations can need 15% or more for cuts and starter/cap courses. Base the figure on the actual geometry, and confirm whether the spec requires specific starter and ridge products that affect quantities.

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