How Deep Should a Paver Base Be?

Common base depths

These are widely used rules of thumb for compacted crushed-stone base on firm, well-drained soil. Paver manufacturers and local practice may call for more.

Add depth on clay, wet or frost-prone ground. Soft clay soils hold water and move, so many installers add 2 to 4 in of base there and lay a geotextile fabric on the subgrade to keep the base from mixing with the soil.

Why the base matters

Pavers are only as flat as what is under them. A thin or poorly compacted base settles under foot traffic, freezes and heaves, or ruts under car tires. The bedding sand on top is only a leveling layer about 1 in thick. Using a thicker sand layer to make up for a low base is a common mistake, because sand shifts and leaves dips.

How deep to dig

The excavation depth is the base, plus the sand, plus the paver thickness, measured down from the finished surface. Patio pavers are often about 2-3/8 in (60 mm) thick; driveway pavers are often about 3-1/8 in (80 mm).

Excavate 6 to 12 in beyond the paved edge as well, so the base extends under the edge restraint.

Compact in lifts

A plate compactor can only firm up a few inches of stone at a time. Spread the base in layers, often 2 to 4 in each, dampen it slightly, and compact each layer before the next. A 6 in base is usually two or three lifts. Use crushed angular stone with fines (sold under names such as road base, crusher run or dense-graded aggregate). Round stone like pea gravel will not lock together.

Worked example: patio

A 12 × 16 ft patio is 192 sq ft. With a 4 in base you need 2.37 cubic yards of compacted base, roughly 3.3 tons. On clay with a 6 in base it is 3.56 cubic yards, about 5 tons. A 1 in sand bed adds 0.59 cubic yards (16 cu ft), which is 32 bags of 0.5 cu ft. Suppliers deliver loose stone, so add about 10 percent for compaction when you order.

Worked example: driveway

A 10 × 40 ft driveway is 400 sq ft. A 10 in base takes 12.35 cubic yards, about 17.3 tons of crushed stone, and the 1 in sand bed takes 1.23 cubic yards. Driveways see far heavier loads than patios, and soil and climate matter more, so it is worth asking a local paver installer or your supplier what base depth works in your area.

Base per 100 square feet

A quick reference for compacted base at about 1.4 tons per cubic yard. Scale it to your area.

Metric example

A 20 m² patio with a 150 mm base needs 3 m³ of compacted base, about 5 tonnes, and a 30 mm sand bed needs 0.6 m³.

Slope and drainage

Shape the subgrade and the base to the same fall you want on the finished surface, so water drains through the whole system, not just across the top. A common target is about 1/4 in per foot (2 percent) away from the house. Never slope a patio toward a foundation.

Safety

• Call your utility-locating service before excavating.
• Wear hearing protection with a plate compactor, and keep feet clear of the plate.
• Cut pavers wet or with dust extraction and wear a suitable mask, because concrete dust contains silica.

Enter your area and depths in the paver calculator to get pavers, base and sand together, or use the gravel calculator for other stone types.

Frequently asked questions