What waste factor should I use?

It depends on the material and layout. Common figures: drywall 10 percent for simple rooms and 15 percent with many openings; roofing 10 percent for a simple gable and 15 percent with hips and valleys; tile 10 percent straight and 15 percent diagonal.

Is a waste factor the same as overage?

Yes, mostly. Overage and waste factor both mean the extra you order above the measured quantity. Concrete crews often call it over-order and add 5 to 10 percent.

What is a waste factor in construction?

A waste factor is the percentage added to a measured quantity to cover cuts, offcuts, breakage and mistakes. It is applied after the takeoff: measured quantity x (1 + waste) = order quantity. Simple layouts often take about 10 percent; cut-up roofs and diagonal or herringbone tile take 15 to 20 percent.