Waste Factor by Material
How much extra to add for cuts and offcuts — by material and layout.
Every material order should include a waste allowance — the extra you buy to cover cuts, offcuts, breakage, and mistakes. Too little and you make a second trip; too much and you've overspent. Here are sensible starting points by material.
Typical waste factors
| Material | Typical waste | Notes |
|---|---|---|
| Flooring (straight lay) | 5–10% | Up to 15% for diagonal patterns |
| Tile | 10% | 15–20% for diagonal or herringbone |
| Drywall | 10–15% | Cuts around doors, windows, outlets |
| Roofing shingles | 10% | 15%+ for many hips and valleys |
| Decking | 10% | More for angles and picture-frame borders |
| Concrete | 5–10% | Spillage and uneven subgrade |
The pattern is simple: the more cuts a layout needs, the more waste you should plan for. Straight, rectangular installs sit at the low end; diagonal, curved, or heavily interrupted ones sit at the high end. When in doubt, round up — a spare box also covers future repairs, and dye lots change between production runs.
Frequently asked questions
Why do I need to add a waste factor?
Cuts, offcuts, breakage, and mistakes mean you can't use 100% of what you buy. A waste allowance keeps you from coming up short mid-job.
How much waste for a diagonal tile layout?
Plan for 15–20% — diagonal and herringbone patterns produce many cut tiles you can't reuse.
Is it better to over-order?
A modest over-order is wise — a spare box or two covers future repairs and avoids a costly second trip, since dye lots and batches vary.