Every takeoff needs a waste allowance: offcuts, breakage, mistakes, pattern matching, and the bag or tin that gets rained on. Too little and you're back at the supplier mid-job, losing time that costs more than the material. Too much and the profit sits in a pile behind the van. The right figure depends on the material, the layout and the site.
Typical allowances
| Material | Typical | Go higher when… |
|---|---|---|
| Ready-mix concrete | 5–10% | Uneven base, hand-dug, pumped |
| Bricks and blocks | 5% | Reclaimed brick, many openings or piers |
| Framing timber | 10% | Complex walls, lots of openings |
| Sheathing / sheet goods | 10% | Roofs with hips and valleys: 12–15% |
| Plasterboard | 10–12% | Short walls, sloped ceilings, many openings |
| Laminate / LVP / wood | 7–10% | Diagonal 15%, herringbone 20% |
| Tile | 10% | Large format, diagonal, many cuts: 15%+ |
| Carpet | Varies | Set by the roll width, not a percentage |
| Roof tiles and slates | 10% | Hips, valleys and dormers: 15–20% |
| Deck boards | 10% | Picture frames, diagonal layouts |
| Trim and moulding | 15% | Many corners and short runs |
| Paint | 5–10% | Rough surfaces, spraying |
| Mulch, gravel, soil | 5–15% | Loose soil settles 15–20% |
Where waste really comes from
- Cutting: every cut leaves an offcut, and many can't be reused. The more corners, openings and angles, the more waste.
- Pattern: diagonal and herringbone layouts waste far more than straight ones, because every edge piece is a cut.
- Stock length fit: buying lengths that don't suit the runs.
- Breakage and defects: chipped tiles, split boards, warped studs.
- Handling and weather: bags that get wet, sheets damaged on delivery.
- Mistakes: mis-cuts happen, especially on complex work and with less experienced crews.
Waste isn't only offcuts
Allow for stock length fit. If every run of trim is 3.4 m and you buy 2.4 m lengths, the waste will be far more than 10% unless you plan the joins. Good takeoffs choose stock lengths to suit the runs. The calculators do this for framing, decking and trim.
Waste on small jobs
Percentages break down on small jobs. A 10% allowance on a single small bathroom floor might be a fraction of a box, but you can only buy whole boxes. On small jobs, round up to the next pack and think in units, not percentages.
Keep spares for the client
For tile, flooring and roof coverings, leave a few spares with the client for future repairs. Batches change, and a matching tile three years later can be impossible to find. Say so in your quote. Clients appreciate it, and it explains why the order includes a little extra.
Returns
Ask your supplier about returns before ordering. Many will take back full, unopened boxes and bags within a set period, sometimes with a restocking fee. If returns are easy, you can afford to order a little more and send back what's left. Special orders and cut-to-length items usually can't be returned.
Waste in your price
The client pays for the waste either way, so be open about it. Showing quantities that include waste, rather than hiding a fudge factor in the unit price, makes your quote easier to compare and defend.
Track your real waste
The best waste figure is your own. After each job, compare what you ordered with what you used, and adjust your defaults. Every TakeoffYard calculator lets you set the waste allowance per job, so your own numbers carry into every quote.
Common questions
Should I add waste before or after rounding to packs?
Before. Work out the area, add the waste percentage, then round up to whole boxes, bags or sheets.
Do experienced crews need less waste?
A little, on straightforward work. But layout, room shape and material matter far more than skill. Herringbone wastes material for everyone.
What about waste on labour?
The equivalent of material waste in labour is lost time: setting up, cleaning up, waiting for deliveries and fixing mistakes. Build it into your rates with realistic billable hours, as the labour rate guide explains.
This guide is general information for estimating. It is not engineering, legal or tax advice. Check the NCC, Australian Standards and your building surveyor or certifier for your project.