Building a Paver Patio: Base Depth, Sand and Materials Needed

Most paver patios that fail do so because of what is underneath, not the pavers themselves. A patio that is laid on a properly compacted 4 to 6 inch crushed-stone base, with a 1 inch bed of sand and a firm edge, will last decades. This guide explains each layer, how deep it should be, and how to order the right amount of each material.

The layers, from the ground up

1. Compacted soil (subgrade). Remove sod and topsoil, which is soft and organic. Dig down to firm soil and compact it. Soft or wet spots should be dug out and filled with stone.
2. Geotextile fabric (optional but useful). On clay or soft soil, a fabric layer stops the base stone sinking into the subgrade.
3. Base layer. Crushed stone with fines (road base or "crusher run") compacted in lifts. This is the structural layer.
4. Bedding sand. A 1 inch screeded layer of coarse concrete sand, which allows the pavers to be set level.
5. Pavers. Laid on the sand and tapped into place.
6. Edge restraint. Plastic, metal or concrete edging that stops the pavers spreading sideways.
7. Joint sand. Swept in to lock the pavers together. Polymeric sand hardens slightly and resists weeds and washout.

How deep should the base be?

• Patios, walkways and pool decks (foot traffic): 4 to 6 inches of compacted base.
• Driveways and areas with vehicles: 8 to 12 inches, in layers, and often more on soft soil.
• Clay soils or places with frost: go to the deeper end of each range, and check what local installers and your supplier recommend. Frost heave is the enemy of pavers.

Install the base in layers ("lifts") of about 4 inches or less, and compact each with a plate compactor. A hand tamper works for very small areas, but is hard work and rarely gives the same density.

How much material do you need?

Take a 12 × 12 ft patio (144 ft²) with a 4 inch base, a 1 inch sand bed, and 6 × 9 in pavers:

If you pick 4 × 8 in brick pavers instead, you need about 713 for the same patio, and 12 × 12 in pavers need 159. For a 6 inch base on the same patio, order about 3.2 yd³ (4.5 tons) of stone. The paver calculator does these sums for any size.

Why the extra 20% on the base? Loose stone compacts by about a fifth, so you need to order more than the finished volume. The sand bed does not compact much, so it is ordered as is.

Step by step

1. Plan the layout and slope. Slope the patio away from buildings by about 1/4 inch per foot (about 2%) so water drains. Set string lines at the finished height, and work backward to find the dig depth.
2. Dig. Excavate to the depth of base + sand + paver thickness. Call 811 first in the US to find buried lines.
3. Compact the subgrade, then add fabric if needed.
4. Add and compact the base in layers, wetting it lightly and running over it several times. Check the slope with a level and string.
5. Screed the sand. Lay pipes or rails at the right height, pull a straight board across them, and fill and re-screed the low areas. Do not walk on the finished sand.
6. Lay the pavers from a corner or a straight edge, working outward and placing them down onto the sand, not sliding them. Stop for any cut pieces and finish them at the end.
7. Install the edge restraint and spike it into the base.
8. Compact the pavers with a plate compactor fitted with a pad, then sweep joint sand over the surface and compact again. Top up the joints.

Mistakes to avoid

• A shallow or uncompacted base. The number one cause of sinking, rutting and heaving.
• Using stone dust or fine sand as the base. It holds water and shifts. Use an angular, graded stone.
• Too much bedding sand. More than about 1 inch (or using it to level a poor base) means the pavers settle unevenly.
• Skipping the edge restraint. Without it, the pavers at the edge creep outward and the joints open up.
• No slope. Water ponding on or against the house causes damage and ice.