Waste Factor
general
The percentage added to a material estimate to cover cuts, breakage, and spillage — typically 5% to 15% depending on the material and layout.
Waste is not padding; it is the material that physically cannot end up in the finished work. Every perimeter cut generates an offcut too small to use, tile breaks during cutting, concrete is left in the chute and the wheelbarrow, and lumber is culled for defects. The right figure varies by material and by layout: a straight-lay tile floor needs 10%, the same floor on a diagonal needs 15% because every perimeter tile is cut at an angle and the offcuts rarely fit elsewhere. Apply waste to the measured quantity — never build it into the measurement itself, or you lose the ability to see what you are actually paying for.
Example
Typical figures: concrete 5–10%, tile 10% (15% diagonal), flooring 10%, roofing 10–15%, hardwood 20–30%, paint 0%.
Common mistake
Adding a waste factor to paint. Manufacturer coverage figures already account for normal application loss, so a percentage on top simply over-orders. What actually changes paint quantities is surface porosity, not waste.
Related Terms
- Roofing Square — A unit of roof area equal to 100 square feet — the unit shingles are sold and qu…
- Coverage Rate — How much area one unit of a material covers — square feet per gallon of paint, p…