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Roofing & Siding Material Calculators

Calculate roof pitch multipliers, roofing squares, architectural shingle bundles (3 bundles/square), underlayment rolls, starter strips, and vinyl siding cartons.

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Roofing Pitch & Exterior Siding Takeoff Standards

Contractor standards for roof squares, pitch multiplier calculations, and vinyl siding overlap expansion.

Roofing Squares Definition

In roofing, 1 "Square" equals exactly 100 square feet of sloped roof area (10 ft × 10 ft). Standard architectural shingles are packaged at 3 bundles per square, meaning each bundle covers approximately 33.3 square feet.

Pitch & Slope Multipliers

Roof pitch determines the true surface area. A common 6/12 pitch has a multiplier of 1.118 (a 2,000 sq ft flat footprint equals 2,236 sq ft of pitched surface). Steeper 8/12 pitches increase surface area by 20.2% (1.202 multiplier).

Underlayment & Ice/Water Shield

Synthetic roof underlayment rolls cover 10 squares (1,000 sq ft) per roll with superior tear resistance compared to traditional 15lb/30lb asphalt felt. Self-adhering Ice & Water shield must be placed 3 to 6 feet up eaves and in valleys.

Vinyl Siding Packaging & Accessories

Vinyl siding is shipped in 2-square cartons (200 sq ft per box). Always calculate 10ft starter strips along all bottom foundation perimeters and 12.5ft J-channels around the perimeter of all window and door casings.