Built-Up Roofing Roofing Calculator
Estimate how much built-up roofing your roof needs and what it will cost. Enter your roof size and pitch to get squares, material quantities, and a budget range — with the 5% waste allowance built-up roofing typically requires.
- Estimated Packs
- 9 packs
- Effective Area per Shingle
- 784 sq in
- Waste Factor Used
- 10%
Enter your values and press Calculate to see your result.
About Built-Up Roofing (Flat)
Traditional hot-tar-and-gravel system for flat or low-slope roofs.
When measuring for a built-up roofing (flat) roof, it's critical to account for the correct waste factor. The typical waste factor for this material is 5%, which ensures you have enough material to cover hips, valleys, and starter strips without running short.
How the Roofing Materials Calculator | Calculate Shingles & Wood Works
Follow the exact steps to get your result instantly and privately.
Step 1: Wood Shingle Roofing
Wood shingles are thin, tapered pieces of wood which are treated with fire retardant. They are used because of their beautiful loo...
Step 2: Clay Tile Roofing
Clay tile roofing is maybe the oldest form of roofing. We find clay tiles as early as the 3rd millennium BC in ancient Mesopotamia...
Step 3: Metal Roofing
Metal roofing is also an old solution - we find it in 27 B.C. with Romans using copper for the Pantheon. It has a few advantages l...
Step 4: Asphalt Shingle Roofing
Asphalt roofing is one of the most common forms of roof covering because it is cheap, easy to install and easy to maintain. Typica...
Step 5: Slate Roofing
Slate is a natural stone created by intense heat and pressure produced by ancient seas. The stone can be split into thin sheets, i...
Step 6: Flat Roof Covering Solutions
There are more types of flat roof coverings like PVC, rubber, bitumen, and tar and gravel. PVC or vinyl is very light, long-lastin...
Step 1: Wood Shingle Roofing
Wood shingles are thin, tapered pieces of wood which are treated with fire retardant. They are used because of their beautiful look, durability and high-wind resistance. Calculating materials requires accounting for the specific reveal and overlapping nature of wood shakes.
Frequently Asked Questions
Clear answers about roof square footage calculations, pitch slope factors, shingle bundles, and ordering materials.
Built-Up Roofing runs about $400–$800 per roofing square installed, where one square covers 100 square feet. On a typical 2,000 sq ft roof (20 squares) that works out to roughly $8,000–$16,000, depending on your region, roof complexity, and local labor rates.
Plan for about 5% waste with built-up roofing. That allowance covers offcuts at hips, valleys, ridges, and starter courses, plus a few spare pieces for mistakes and future repairs. Steeper, more cut-up roofs sit at the higher end of the range.
A well-installed built-up roofing roof lasts 15-30 years. Traditional hot-tar-and-gravel system for flat or low-slope roofs. Regular inspections and prompt flashing repairs help you reach the upper end of that range.
Divide your total sloped roof area by 100 to get the number of squares, then add 5% for waste. For example, a 2,400 sq ft roof is 24 squares; with 5% waste you would order about 25.2 squares of built-up roofing.
Still have questions about your roof takeoff?
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