What is Roof Waste?
Roof waste is the extra roofing material needed beyond the actual roof area to account for cutting, fitting, defects, and installation losses. Accurately estimating waste prevents mid-project material shortages and avoids over-ordering. Most roofing projects require 10 to 15 percent additional material.
How to Calculate Roof Waste
Here is the formula:
[\text{Waste} = \frac{\text{Roof Area} \times W}{100}]
Where:
- Waste is the additional material needed.
- Roof Area is the total roof surface area.
- W is the waste percentage.
The total material to order is the roof area plus the waste amount.
Calculation Example
A roof area of 600 ft² with an estimated waste percentage of 13.
[\text{Waste} = \frac{600 \times 13}{100} = 78]
You need an extra 78 ft² of material, for a total order of 678 ft².