What Goes Under Pavers: Base, Sand and Depth
A paver patio is mostly what you cannot see. The pavers are the easy part; everything that decides whether it stays flat is underneath.
Six inches of compacted crushed stone, then one inch of concrete sand. For a driveway, ten to twelve inches of stone instead of six.
The layers
| Layer | Material | Patio | Driveway |
|---|---|---|---|
| Subgrade | Native soil, compacted, sloped to drain | — | — |
| Separator | Geotextile over soft or clay ground | — | — |
| Base | Crusher run / dense-grade crushed stone | 6 in | 10–12 in |
| Bedding | Concrete sand | 1 in | 1 in |
| Pavers | — | — | — |
| Joints | Polymeric or joint sand, swept in | — | — |
The bedding layer is one inch and stays one inch. It is there to seat the pavers, not to fix the levels — that is the base's job. Using two or three inches of sand to correct a dip is the single most common cause of a patio that ripples within a year.
Why crusher run below and concrete sand above
They want opposite properties, which is why they are different materials.
The base wants to lock solid. Crusher run is angular stone with the fines left in, so it compacts into something close to a slab. Washed stone would stay loose.
The bedding wants to stay loose but not move. Concrete sand is coarse and angular, so the grains interlock under load. This is where play sand fails — its rounded grains roll, and the pavers settle unevenly. See types of sand.
Compaction is the step that matters
Compact the base in lifts of three to four inches, not all at once. A plate compactor cannot densify a foot of loose stone from the top; it packs the surface and leaves the bottom soft, which shows up as a dip two winters later.
Do not compact the bedding sand before laying. Screed it, lay the pavers on it undisturbed, then compact the whole surface once at the end, which beds the pavers into the sand.
Slope, before anything else
Build the fall into the subgrade, not into the sand. About an inch every eight feet, away from any building. Water that cannot run off sits in the base, and a saturated base heaves in the first freeze.
How much to order
For a 10 by 12 ft patio (120 sq ft):
- Base at 6 in — 2.2 cubic yards, about 3.1 tons of crusher run
- Bedding at 1 in — 0.4 cubic yards, about 0.5 tons of concrete sand
For a 20 by 20 ft driveway apron (400 sq ft) at 10 inches of base, that is 12.3 cubic yards or about 17 tons — a proper delivery, and worth reading will a dump truck damage my driveway before it arrives.
Both are sold by the ton; how much gravel do I need has the conversion. Add about 10% to the base for compaction.
The unprofitable part
If the ground is soft, boggy or recently filled, more base will not save it. Excavate to something firm, or accept that the patio will move. A properly built six inches over solid ground outlasts twelve inches over made-up ground every time, and costs less.
Find base stone and sand suppliers near you on Topsoil.com.
The same build carries flagstone, provided the stone is thick enough to dry-lay — how much flagstone do I need has the coverage per ton and the thickness that decides it.