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Gravel & aggregates

Depths, weights, sub-base specs and what 'tonne per cubic metre' actually buys you.

All guides
Stub — growing
Last reviewed
2 sources
Regulations
  • Loose gravel in a front garden is permeable and counts as SuDS-friendly under GPDO Class F. [1]
  • MOT Type 1 is specified to the Specification for Highway Works — Series 800. Use it for sub-bases under paving and driveways. [2]
Hints & tips
  • Loose gravel decorative depth: 40–50 mm over a permeable membrane. Less and the membrane shows through; more and it walks.
  • Bulk density rules of thumb: gravel ~1.5 t/m³, MOT Type 1 ~2.0 t/m³ compacted, sharp sand ~1.6 t/m³.
  • Always add a 5–10 % over-order on bulk aggregates — voids, spillage and the bottom of the bag are real.
  • Bulk bags are nominally 1 tonne but actual mass varies ±10 %; weighbridge tickets are the only honest source.

This app provides general UK guidance and material estimates only. It is not legal, planning, engineering or building-control advice. Always confirm requirements with your local planning authority, building control, utility providers, manufacturers or qualified professionals.