Pavers fail from the bottom up. Sunken ruts, rocking pavers and weeds almost always trace back to too little base, poor compaction or bad drainage. Estimate the layers properly and the pavers take care of themselves.
The layers
- Excavation: the total depth of every layer, plus the paver thickness, minus how high the finished surface sits above the ground.
- Sub-grade: the natural ground, compacted. Remove soft spots.
- Geotextile on clay or soft soils.
- Sub-base: MOT Type 1, compacted in layers.
- Bedding: 30–50 mm of sharp sand, screeded.
- Pavers and edge restraint.
- Joint sand: kiln-dried sand, swept in and compacted.
How thick?
| Use | Sub-base |
|---|---|
| Paths and patios | 100 mm |
| Driveways (cars) | 150–200 mm |
| Poor or clay ground | Add 50–100 mm and geotextile |
Fall
Patios need a fall away from buildings so water drains: about 1:60 to 1:80. Build the fall into the base, not the sand bed.
Quantities
Pavers = area ÷ (paver + joint module), plus 5–10% waste, or 12–15% for herringbone and curves. Base volume = area × depth, plus about 20% for compaction. The paver calculator works out every layer, the joint sand and the edging in one go.
Don't forget
- Removing the dug soil, which swells when dug
- Plate compactor and cutter hire
- Drainage channels at thresholds
- Keeping the finished level below the damp-proof course: 150 mm below DPC is the usual rule
This guide is general information for estimating. It is not engineering, legal or tax advice. Check the Building Regulations and Building Control for your project.