How deep to go
| Use | Published figure | Source |
|---|---|---|
| Gravel shed pad depth | 4 to 6 in | siteprep.com |
| Pad size beyond the shed | 12 in on every side | siteprep.com |
Site Prep, which builds shed pads, puts the depth at 4 to 6 inches and makes the pad extend 12 inches past the shed in each direction, so a 10 × 12 ft shed sits on a 12 × 14 ft pad. Its crews use crushed stone, not rounded river gravel, which it says is not suitable for a foundation.
Working it out
Cubic yards = area (sq ft) × depth (in) ÷ 12 ÷ 27. Tons = cubic yards × weight per cubic yard.
Example: 14 × 12 ft at 4 inches with 10% extra is 2.28 cubic yards of no. 57 stone, about 2.94 tons at 1.29 tons per cubic yard.
Rochester Concrete Products' install guide adds 10% for compaction and uneven ground.
Common questions
How much gravel do I need for a shed base?
Measure the area, choose a depth from the table above and enter both in the calculator. It gives cubic yards, tons and bags.
Should I order extra?
Rochester Concrete Products' install guide adds 10% for compaction and uneven ground. Loose stone also compacts, so a compacted layer needs more loose material than its finished depth suggests.
Related calculators
Sources
- https://www.siteprep.com/how-much-gravel-for-a-shed-foundation/
- https://www.siteprep.com/gravel-shed-foundation-12-wider-shed/
- https://new.siteprep.com/?p=553
- https://www.fhwa.dot.gov/publications/research/infrastructure/structures/bridge/15034/003.cfm