Paver Base Depth: How Much Gravel Under Pavers?
Short answer: under a patio or walkway, compact 4 to 6 inches of crushed-stone base; under a home driveway, 6 to 8 inches. On top goes 1 to 1½ inches of bedding sand, then the pavers. These are the minimums from the Concrete Masonry & Hardscapes Association (CMHA, which took over the Interlocking Concrete Pavement Institute). Go deeper on soft, wet or clay soil and where the ground freezes.
To turn your area into tons of gravel, sand and a paver count, use the paver calculator.
Base depth by use
| What the pavers carry | Compacted base | Paver thickness |
|---|---|---|
| Patio, walkway, pool deck | 4 to 6 in | 2⅜ in |
| Home driveway | 6 to 8 in | 2⅜ in (3⅛ in for heavy use) |
| Street, parking lot | 8 to 12 in | 3⅛ in, designed by an engineer |
The base is crushed stone with fines (often sold as road base, crusher run or ¾ in minus), not round gravel. Round stone rolls and never locks together.
How deep to dig
Add the three layers: base, sand and paver. With 2⅜ in pavers and 1 in of sand:
| Base | Dig below finished surface |
|---|---|
| 4 in | about 7½ in |
| 6 in | about 9½ in |
| 8 in | about 11½ in |
Dig the base out wider than the pavers too. With plastic or metal edging held by spikes, CMHA has the base run past the spikes, by up to 10 in on home projects.
How much base gravel to order
Compacted volume is area × depth. Loose gravel shrinks when you compact it, so the calculator adds 15%, then converts at about 1.42 tons per cubic yard:
| Area | 4 in base | 6 in base | 8 in base |
|---|---|---|---|
| 100 sq ft | 1.42 cu yd (2.01 t) | 2.13 cu yd (3.02 t) | 2.84 cu yd (4.02 t) |
| 200 sq ft | 2.84 cu yd (4.02 t) | 4.26 cu yd (6.04 t) | 5.68 cu yd (8.05 t) |
| 300 sq ft | 4.26 cu yd (6.04 t) | 6.39 cu yd (9.06 t) | 8.52 cu yd (12.07 t) |
| 500 sq ft | 7.10 cu yd (10.06 t) | 10.65 cu yd (15.09 t) | 14.20 cu yd (20.12 t) |
Bedding sand
Use coarse concrete sand (ASTM C33), screeded to an even 1 to 1½ in and left loose: the pavers settle into it when you run the plate compactor over them. CMHA warns against two common substitutes:
- Mason sand drains slowly and shifts. Keep it for the joints.
- Stone dust or screenings hold water because of their fine particles.
At 1 in, bedding sand takes about 0.31 cu yd (0.40 tons, or 17 bags of 0.5 cu ft) per 100 sq ft.
Getting the base right
- Compact the soil first, then lay the base in layers (lifts) of about 4 to 6 in, compacting each one. One thick layer only gets packed on top.
- Get it flat: CMHA’s tolerance is ±⅜ in under a 10 ft straightedge.
- Fix dips with base, not sand. Extra sand in a low spot settles and shows through as a dip in the pavers.
- Slope it for drainage, away from the house, the same as the finished surface.
- On fine clay soil, a geotextile fabric between soil and base stops the two mixing.
Common questions
Can I put pavers straight on dirt or sand?
Not if you want them to stay flat. Without a compacted stone base, pavers sink and shift, especially after freezes and heavy rain.
Is 4 inches of base enough for a patio?
It is the minimum, and fine on firm, well-drained soil. Use 6 in on clay, wet ground or where frost is deep.
How thick should the base be for a driveway?
6 to 8 in of compacted crushed stone for a home driveway. Streets and parking lots need an engineered design.
How much does a ton of base gravel cover?
About 50 sq ft at 4 in deep, or about 33 sq ft at 6 in, using the table above.
Sources
- CMHA PAV-TEC-010: Application Guide for Interlocking Concrete Pavements (revised 2022): base and paver thickness, bedding sand, lifts, tolerances, edge restraints.
- Engineering ToolBox: densities of dirt, sand and gravel: dry gravel 105 lb/ft³, dry sand 97 lb/ft³, used for the tons.