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Contractor glossary

Roofing square

Updated

Definition

A roofing square is 100 square feet of roof surface. Roofers measure roofs, order materials, price labor and compare jobs in squares, so a roof with 2,400 square feet of surface is a 24-square roof.

Also called: Square, SQ

Squares measure the roof, not the house

A square counts roof surface, and a pitched roof has more surface than the house has floor. Overhangs push the edges past the walls, and the steeper the roof, the more material it takes to cover the same footprint.

To get from a footprint to squares, measure the building's outline including the overhangs, multiply by the pitch factor, and divide by 100. The pitch factor is the square root of (rise squared plus 144), divided by 12, where the rise is how many inches the roof climbs per 12 inches of run (see roof pitch).

Pitch Pitch factor 1,000 sq ft of footprint becomes
4/12 1.054 1,054 sq ft (10.54 squares)
6/12 1.118 1,118 sq ft (11.18 squares)
8/12 1.202 1,202 sq ft (12.02 squares)
10/12 1.302 1,302 sq ft (13.02 squares)
12/12 1.414 1,414 sq ft (14.14 squares)

The factor only works for planes that share one pitch. A steep main roof and a shallow porch roof are two measurements, not one.

From squares to a material order

Measured squares are what the roof is. Ordered squares are what you buy, which adds waste for the cuts at hips, valleys, rakes and penetrations. Keep the two numbers separate on the estimate so the homeowner, an adjuster and your crew can each see where the order came from.

Example: A ranch house with a simple gable roof measures 50 by 30 feet including the overhangs, a 1,500-square-foot footprint. At 6/12, the roof surface is 1,500 × 1.118 = 1,677 square feet, or 16.77 squares. Say your records on simple gables support a 10% waste allowance (a made-up figure for this example): 16.77 × 1.10 = 18.45 squares of field shingles. If the wrapper on the shingle you're using says three bundles cover a square, that's 18.45 × 3 = 55.35, so you order 56 bundles. Starter and ridge cap come from the linear feet of eaves, rakes and ridge, not from the squares.

Where squares show up in the business

  • Supplier orders. Field shingles and underlayment are ordered from the squares; accessories are ordered by the linear foot or by the piece.
  • Labor. Install labor is often priced and tracked per square. Logging squares installed per crew day is a simple piece of job costing, and it's where your labor price should come from.
  • Tear-off and disposal. Old roofing comes off by the square, and every extra layer adds labor and weight, so price tear-off per square, per layer.
  • Insurance claims. Adjusters' estimates usually list roofing in squares too. Writing your quantities in the same units makes an insurance supplement easy to match line by line.

Price per square is handy for comparing jobs, but it's a result, not a starting point. How to price roofing jobs builds a price from measurements, waste, layers and line items, and divides by the squares only at the end.

Common mistakes

  • Using the floor plan or living area. It ignores pitch and overhangs, so every number downstream comes out short.
  • One pitch factor for a mixed roof. Measure each section at its own pitch.
  • Assuming bundles per square. Coverage varies by product. Read it off the wrapper or the manufacturer's spec sheet.
  • Applying field waste to everything. Starter, ridge cap and drip edge are measured by length, so figure their overage from the linear feet, not from the field-shingle percentage.
  • Quoting a bare price per square. Per-square numbers only compare if they cover the same layers, accessories, flashing and decking terms.
  • Rounding down. You can't buy part of a bundle, and a short order costs a supply run mid-job.

How it connects

Squares are the core quantity on a roofing estimate and in the scope of work the homeowner signs. How to write a roofing estimate shows how to present measured squares, pitch and waste so the homeowner and the adjuster can follow your numbers.

Go deeper

Roofing guideHow to Price Roofing JobsPrice roofing jobs from real measurements: squares, pitch factors, waste, tear-off layers, decking allowances, code line items and insurance work.Roofing guideHow to Write a Roofing EstimateWhat goes in a roofing estimate: squares with pitch and waste, line items adjusters expect, code items, decking allowances, photos, warranties and payment terms.Roofing guideHow to Invoice Roofing Jobs (Including Insurance Claims)How roofers invoice retail and insurance jobs: allowances, ACV and depreciation checks, deductibles, supplements, mortgage checks and lien waivers.
Roof pitchRoof pitch is how steep a roof is, written as the inches it rises for every 12 inches of horizontal run, such as 6/12. Pitch decides how much real surface sits over a footprint, how fast crews can work and what safety setup and materials the roof needs.EstimateAn estimate is a contractor's expected price for a job, based on the scope as it's understood before work starts. It tells the customer the price could change if the work turns out different, but whether it binds you depends on its wording, the customer's acceptance and your state's law.Insurance supplementAn insurance supplement is a request, made on the homeowner's claim, asking the insurer to add work or quantities its original estimate missed. On a roof, it usually covers items found at tear-off or measured short, backed by photos, measurements and line-item prices.Job costingJob costing is recording what each job actually cost (materials, labor at its full hourly cost, subcontractors, permits, disposal and return trips) and comparing it with the estimate and the price, so you can see which jobs made money, which didn't and why.Scope of workA scope of work is the written description of exactly what a job includes and what it excludes: the tasks, materials, quantities, locations and standards of finish. It's the part of an estimate or contract that defines what the price buys, so anything outside it needs a change order.

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