1. What a waste factor covers
A waste factor is an allowance added to exact quantities to cover offcuts, defective pieces, saw kerf, and honest mistakes. It is not padding for guesswork; it is the difference between exact math and a realistic shopping list.
2. Picking 5, 10, or 15 percent
- 5%: simple rectangular decks with long straight runs and little cutting.
- 10%: a solid default for most residential decks.
- 15%: diagonal layouts, picture-frame borders, herringbone, or many angles.
3. Patterns that need more
Diagonal decking increases cut waste because each board meets the rim at an angle. Borders and inlays create short offcuts. Small, choppy decks can waste more per square foot than large simple ones. When in doubt, move up one step.
Note
A waste factor never replaces careful measuring or a good cut plan. It reduces the risk of a second trip to the store.
4. Worked example
If your exact decking need is 416 linear feet:
5% -> 436.8 ft
10% -> 457.6 ft
15% -> 478.4 ft
10% -> 457.6 ft
15% -> 478.4 ft
Every calculator on this site lets you apply these factors directly. See the board calculator.