Roof guide
Roof waste guide
Waste depends on the material and the roof geometry. Use a realistic allowance so the order covers cuts, overlaps, and edge work.
Membranes and sheets
Overlap and seam waste is usually small, but trims and penetrations still add up.
Boards and panels
Cuts around edges and openings can increase the waste factor more than expected.
Tiles and battens
Ridges, hips, valleys, and break lines can all increase the final ordering requirement.
Example
Waste example
A roof with complex edges may need 10 to 15 percent waste instead of a basic 8 percent allowance.
The calculator lets you change the allowance so you can match the roof type and product system.