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Units of Measureaka: roofing squareaka: SQ

Square (roofing)

In Plain English

A roofing unit equal to 100 square feet of roof area.

Definition

In roofing, a square is a unit of measure equal to 100 square feet of roof surface area. Roofing materials—including shingles, tiles, underlayment, and built-up roofing—are specified, estimated, and priced per square. Contractors measure roof area by calculating the total number of squares, accounting for slope and waste factors, to determine the quantity of materials to order.

Why It Matters in Bidding

The square is the pricing and ordering unit for nearly all roofing work, so estimators convert measured roof area into squares, apply slope and waste factors, and then price materials and labor per square. Getting the square count wrong, or underestimating waste on hips, valleys, and steep pitches, directly understates both material orders and the roofing sub's labor.

Example

Taking off a gable roof, the estimator measures 2,400 square feet of surface, divides by 100 to get 24 squares, then adds a 10 percent waste factor before pricing shingles and underlayment per square.

Related Terms

Square FootUnit PriceLinear Foot

Frequently Asked Questions

Divide the total roof surface area in square feet by 100 to get squares, then add a waste factor for cuts at hips, valleys, ridges, and penetrations. Remember to use the sloped surface area, not the building footprint, since pitch increases actual roof area well beyond the plan dimensions.
Waste depends on roof complexity: simple gable roofs run low waste, while roofs with many hips, valleys, dormers, and cut-up planes need substantially more. Estimators base the percentage on the specific geometry rather than a flat number, because under-ordering forces costly small reorders and disrupts the crew's schedule.
Roofing manufacturers package and sell shingles, underlayment, and accessories in bundles tied to coverage per square, so quoting and ordering in squares aligns directly with how material ships. Estimators and suppliers speak in squares to avoid conversion errors when leveling roofing subcontractor bids.

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