Paver Base Calculator

The base is the project

Paver failures are almost never paver failures. They are base failures — settling, rutting, and edge collapse that show up as uneven or shifting pavers a year or two after installation. Getting the base right is the whole job; laying the pavers is the easy part at the end.

Why the base extends past the pavers

This calculator adds six inches of base beyond the paver edge on every side, and that overhang matters more than its small cost suggests. The perimeter of a paver field is where failure starts, because the outermost pavers have support on only one side. The extended base carries the edge restraint and stops the whole field creeping outward.

Crusher run, not washed stone

The base must contain fines. Crusher run, sold regionally as #411, QP, dense-grade, or road base, has stone dust mixed through it that fills the voids and locks the layer into something close to a soft pavement under compaction. Washed stone like #57 will never do this — it stays loose, and pavers set on it will move.

Compact in lifts, screed the sand

Compact the base in two-inch lifts. A plate compactor cannot densify more than about two to three inches per pass, so a single pass over a six-inch base leaves most of it loose.

The bedding sand is different: screed it flat to a consistent one inch and then leave it alone. Do not compact bedding sand before laying pavers — the pavers themselves are compacted into it at the end, and pre-compacting the sand prevents them seating evenly.

Depth by traffic

Four inches of compacted base for walkways, five to six for patios, and ten to twelve for anything carrying vehicles. Add one inch of bedding sand in every case, plus the paver thickness, to get your total excavation depth. Under-building a driveway base is the most expensive version of this mistake, because the repair means lifting every paver.