CSLB C-39 Roofing ContractorEstimating and PlanningEasy

A client's roof requires 21 squares of standard three-tab asphalt shingles. Each bundle covers 33.3 square feet, meaning three bundles equal one square. How many bundles must be ordered for the entire job?

  1. A70 bundles
  2. B21 bundles
  3. C63 bundles
  4. D42 bundles
Show answer & explanation

Correct answer: C. 63 bundles

Standard three-tab shingles are packaged 3 bundles per square. 21 squares × 3 bundles/square = 63 bundles.

Why the other options are wrong

  • A. Overstates the bundle count beyond the correct multiplier.
  • B. Confuses number of squares with number of bundles.
  • D. Uses a factor of 2 instead of the correct 3 bundles per square.

Shingle Bundle Ratio

Standard three-tab asphalt shingles are packaged so that 3 bundles equal exactly 1 roofing square (100 sq ft).

  • 3 bundles = 1 square for standard 3-tab shingles
  • Each bundle covers about 33.3 sq ft
  • Architectural shingles may use different bundle counts

Memory trick: Three's company: 3 bundles make one square.

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