Sub-base and aggregates
Gravel and pea shingle tonnes
- where
- volume (m³)
- area (m²)
- depth (mm)
- material to order (t)
- density as laid (t/m³)
- margin (%)
Explain this equation
This gives the tonnes of gravel, pea shingle or clean stone for a given area and depth, such as a gravel drive top or drainage layer.
A is the area, t the depth in millimetres and V the volume. ρ is the density of the stone and w a margin.
Volume is area times depth, with /1000 converting millimetres to metres; weight is volume times density, plus the margin.
Sense check: 50 mm of gravel over 20 m² is 1 m³, about 1.5–1.7 t depending on the stone.
Watch out: clean single-size stone has more air in it than Type 1, so it weighs less per m³.
Tonnes of gravel, pea shingle or single-size stone for a drive top, path, French drain or drainage layer.
Enter your values to see the result.
Good to know
Caterpillar gives dry gravel as 1.69 t/m³ in place and 1.51 t/m³ loose; pit-run gravel 2.17 in place. Clean single-size stone and pea shingle are near the lower end because of their voids. Aggregate suppliers suggest allowing about 5% extra. Decorative gravel over a sub-base is usually 40–50 mm deep: deeper and it is hard to walk or drive on.
Common mistake
Using the Type 1 density for clean stone. Single-size gravel weighs noticeably less per m³.
Limits
Density varies with stone type and size. Use the supplier’s figure if known.
Sources
Results are calculations from the published methods and figures shown, and depend on the data you enter. Follow BS 8500, BS EN 206, BS EN 752, Building Regulations Part H, manufacturers’ data and your engineer’s design. Structural concrete and foundations need a competent designer.