How it is calculated
The paved area plus a reserve is divided by the area of one paver including the joint. Gravel and sand settle when compacted, so their volumes are multiplied by 1.3 and 1.2. Weight uses a bulk density of about 1.5 t per m³. Kerbs run around the perimeter.
Pavers per m² = 1 ÷ ((length + joint) × (width + joint))Gravel = area × layer × 1.3Sand = area × layer × 1.2Example
A 6 × 4 m patio in 200 × 100 mm pavers needs 1,206 pavers (25.2 m² with a 5 % reserve). For foot traffic that is 4.7 m³ of gravel (about 7 t), 1.2 m³ of sand (about 1.7 t), 20 kerbs of 1 m and 26.4 m² of geotextile.
Tips from practice
- For driveways use 60–80 mm pavers and a 250–300 mm sub-base.
- Fall the surface 1–2 % away from the house so water runs off.
- Compact each layer with a plate compactor and brush dry sand into the joints after laying.
Questions and answers
How many 200 × 100 pavers per square metre?
50 without joints, about 48 with 3 mm joints.
How deep should the sub-base be?
About 150 mm of gravel and 30–50 mm of sand for paths, 250–300 mm of gravel for driveways.
Do I need geotextile?
Yes. It keeps the gravel out of the soil and weeds out of the paving. Lay it on the bottom with an upturn at the sides.
Found a mistake in a formula? Write to [email protected]