In Plain English
Quick Answer
A roofing unit equal to 100 square feet of roof area.
Definition
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.
Context
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
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.
See Also
Related Terms
FAQ
Questions Contractors Ask
How do you convert roof area to squares for a bid?
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.
What waste factor should an estimator add per square?
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.
Why is the square used instead of square feet in roofing?
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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