How Much Wastage to Add
Every material wastes a little — to cuts, breakage and just getting the job done. Here are sensible buffers by material.
Why Wastage Matters
Ordering exactly what the math says means you'll run out. Adding a buffer is the difference between one finished job and a second trip to the supplier.
Recommended Percentages
| Material | Typical Wastage |
|---|---|
| Concrete (slabs) | 5-10% |
| Concrete (complex forms) | 10-15% |
| Tile (straight) | 5-8% |
| Tile (diagonal/pattern) | 10-15% |
| Lumber / decking | 10% |
| Bricks / blocks | 5-10% |
| Paint | 10-15% |
| Roofing shingles | 10% |
Square vs Pattern Waste
Layout drives waste as much as material. Straight-laid flooring and tile waste far less than herringbone, diagonal or heavily cut work.
Round Up at the Register
Apply your percentage, then always round up to the next whole bag, bundle, carton or yard. A small surplus you can return beats a deficit that stops the job.
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Related Calculators
Disclaimer: Figures on this page are general reference information. Always verify exact requirements with your project specifications and a qualified professional.