How much waste should I allow for paving?
Last reviewed 1 July 2026
Short answer
5% for a straight grid on a rectangular patio, 10% for most real patios, and 15–20% for herringbone, circular features or areas with angled edges. Small patios need proportionally more than large ones, because the perimeter — where all the cutting happens — is a bigger fraction of the area.
Work it out for your project with the patio and paving calculator →
Waste happens at the perimeter
Cutting is concentrated at the edges. A 4 m × 5 m patio has 18 m of perimeter for 20 m² of area — 0.9 m of edge per square metre. A 2 m × 2 m patio has 8 m of perimeter for 4 m² — 2 m of edge per square metre, more than twice as much.
That is why a fixed percentage under-serves small areas. On a very small patio, 15% may be barely enough even for a straight grid.
It is also why an L-shaped or stepped patio needs more than a rectangle of the same area: it has more perimeter and more internal corners.
Suggested allowances
| Situation | Allowance |
|---|---|
| Rectangular, straight grid, dimensions divide evenly | 5% |
| Rectangular, straight grid, dimensions do not divide evenly | 10% |
| Running bond | 7–10% |
| Basket weave | 10% |
| Herringbone 45° | 15–20% |
| Any pattern with a curved edge | +5% on top |
| Circular feature or fan pattern | 20–25% |
| Patio under 6 m² | +5% on top |
| Natural stone with variable thickness | +5% — some pieces will be unusable |
Reduce it by setting out first
- Dry-lay a row along the most visible edge before fixing anything. This is where the full slabs should be.
- Push the cuts to the least visible edge, usually against the house or a boundary.
- If the last row would be a narrow sliver, take a little off the first row instead so both ends are a reasonable width.
- Where two patterns meet or the patio changes direction, work outwards from the junction.
- Save usable offcuts. A half slab cut cleanly from one edge is often exactly what the opposite edge needs.
Note: Design out the cutting
Keep the spares
Finish the job with two or three whole slabs left over and store them somewhere dry. Paving cracks, gets stained and occasionally gets broken by a dropped tool.
A replacement bought in three years' time will be from a different batch and will not match — particularly with concrete paving, which fades, and with natural stone, which varies by quarry face.
Safety notice: Material planning only