How much paver base do you need?
A paver patio is three layers on firm, sloped subgrade: a compacted gravel base, a 1 in screeded bed of coarse sand, and the pavers. Work out the base as area × compacted depth × compaction factor. Make the base footprint bigger than the pavers — at least 6 in past every edge, as Quikrete does for patio bases — so the edge restraints sit on compacted stone.
Worked example — a 10×10 ft patio, 6 in base: the base footprint is 11×11 = 121 sq ft. 121 × 0.5 ft = 60.5 cu ft compacted (2.24 cu yd). Crusher run compacts by a third, so order 1.33× — plus 5% for an uneven subgrade — 3.13 cu yd, or about 4.5 tons at 1.45 tons per loose yard. The bedding sand is 100 sq ft × 1 in = 8.3 cu ft: 18 half-cubic-foot bags.
How deep should the base be?
| Project | Compacted base (Unilock) |
|---|---|
| Patio | 6–8 in |
| Walkway | 6–8 in |
| Pool deck | 6–12 in |
| Driveway | 10–14 in |
Unilock's guide adds that clay soil needs the deeper end and sandy soil less. Older bag instructions are thinner — Quikrete's paver sand sheet suggests only 2–4 in of gravel — and that gap explains many sunken patios. Compact the base in lifts of 2–3 in with a plate compactor, and slope it away from the house.
Base stone and bedding
- 3/4 in crusher run (also sold as #411, road base, ABC, CA-6, 21A) compacts hard. Bed pavers on it in 1 in of coarse concrete sand.
- 3/4 in clear stone drains freely and barely compacts by volume. Unilock beds pavers on it with 1/8 in chip stone instead of sand.
- Screed the bedding loose over 1 in pipes, lay the pavers, set edge restraints, then run the plate compactor over the pavers to settle them in. Sweep jointing or polymeric sand into the joints last.
Bags or bulk?
Paver base comes in 0.5 cu ft bags (about 50 lb, $5.37–$7.49) that cover roughly 6 sq ft at 1 in deep; a County Materials pallet is 63 bags. That makes a 10×10 patio about 169 bags — 2.7 pallets — versus about 4.5 tons of bulk crusher run at $24–$34 a ton (American Rock Supply) plus delivery. Above a few hundred pounds, bulk wins easily; bags make sense for a small landing or when the truck can't reach.
Measuring and digging out
Measure the finished paver area, then let the calculator grow the base 6 in past every edge. Edge restraint runs along every side that doesn't butt against the house, steps or another slab — enter those lengths under “Edges against a house” to drop them from the count. Dig to the base depth plus the bedding plus the paver thickness: a 6 in base, 1 in of sand and a 2⅜ in paver means about 9⅜ in below finished grade. That spoil adds up fast — the 10×10 patio above moves 3.5 cubic yards of soil, roughly 5.2 tons in place at the 110 lb per cubic foot Nebraska DOT uses for compacted soil, and more volume once it is loose. Plan a trailer, a dumpster or a spot to regrade it before you start digging.
Order of work
- Mark the layout and have buried utilities located before you dig (Unilock's first step).
- Excavate, then compact the subgrade so the base sits on firm soil.
- Place the base in 2–3 in lifts, compacting each one, sloped away from the house.
- Screed 1 in of bedding over pipes, lay the pavers from a corner, and cut the edges.
- Spike the edge restraints into the base, compact the pavers, then sweep in joint sand.
If you choose to seal the pavers, Unilock suggests resealing every 3–5 years.
Common mistakes
- Ordering the base by its finished depth and running short after compaction.
- Building the base only as big as the patio, so edge restraints have nothing solid to spike into.
- Spreading bedding sand thicker than 1–2 in to fix a lumpy base — pavers then settle unevenly.
- Compacting the bedding sand before laying the pavers.
- Skipping edge restraints. Unilock calls them critical: without them pavers creep sideways.
Patio sizes: 10×10, 12×12, 12×16, 16×20. Pouring concrete instead? Use the slab calculator. Gravel paths and driveways are in the gravel calculator, and bedding sand on its own in the sand calculator.