The base: the structure
The base is a layer of crushed aggregate that is spread in layers and compacted. It carries the load and lets water drain. Its depth is a design choice that depends on soil, drainage, climate and use, and paver manufacturers publish their own requirements, which differ:
- Belgard’s technical guide lists a minimum of 4 in of compacted base for patios and pedestrian areas and 6 in for residential driveways, and notes deeper excavation may be needed in freeze-thaw climates (Belgard Technical Resource Guide).
- Unilock’s planning guide gives typical base depths of 6–8 in for patios and walkways and 10–14 in for driveways, deeper on clay (Unilock Project Planning Guide).
Because the sources disagree, our calculator treats base depth as your choice and never fills one in. Follow the installation guide for the pavers you buy.
The bedding layer: the setting bed
Bedding is a thin, smooth layer the pavers sit on. In sand-set installations both guides above describe about 1 in of screeded sand that is not compacted before the pavers go down. Permeable paver systems use a different bedding material and a different base, so these figures don’t apply to them.
Estimating both
Each layer’s volume is the patio area × its depth. For a 192 sq ft patio:
- 4 in of base: 192 × 4 ÷ 12 = 64 cu ft (2.37 cu yd).
- 1 in of bedding: 192 × 1 ÷ 12 = 16 cu ft.
- Dig depth with 2⅜ in pavers: 4 + 1 + 2⅜ = 7⅜ in.
These are compacted, in-place volumes. Loose aggregate takes up more room before it’s compacted, and installers often extend the base beyond the paver edge. We found no manufacturer or industry figure for a universal loose-to-compacted factor, so ask your supplier how much loose material to order for the compacted depth you want.
Before you dig
Contact 811 a few business days ahead so buried utilities are marked (811 Before You Dig), and slope the finished surface away from your house.