Paver base calculator for Oregon

Stone beneath the pavers costs far less per square foot, yet that lower layer is usually where a failed patio begins. This calculator determines the amount of compacted crusher run or a similar blend, using 1.5 tons per cubic yard: 4 inches for pedestrian areas and 6-8 beneath vehicles, with the +10% compaction allowance selected by default. Calculate bedding sand separately, since it is a fixed 1-inch layer.

Calculating base material

1. Start by measuring the paving footprint in feet. Extend the base 6 inches beyond each exposed paver side so the edge restraint has support beneath it.
2. Patios and walkways need 4 inches of compacted depth. Use 6 under driveways or clay soil, and 8 below driveways built on soft ground.
3. Divide cubic feet by 27 to get yards, multiply by 1.5 to find tons, then turn on the +10% allowance.

Project base depth and coverage

Layers to excavate, from lawn through the finished paver

Set the dig line by totaling each layer. For a typical patio, use 4 inches of base beneath 1 inch of bedding sand and a 2 3/8 inch paver, flush to the lawn. This calls for a 7.5-inch excavation, with adjustment for any reveal above grade. Put the level on a stake and refer to it while digging. Going too deep creates two costs: soil must be hauled off, and stone must replace it. Run the Dirt Calculator backward to estimate the yards removed from the hole.

Sound practices for installing a paver base

• Place the material in 2-inch layers, dampen each one lightly, then compact it with a plate compactor. A little moisture helps the base tighten better than dry aggregate.
• Build the compacted base with a 2-3% pitch leading away from the house. Bedding sand and pavers take on the grade beneath them.
• The 6-inch overhang allows the edge restraint to sit on compacted base rather than lawn soil. Install it there, not directly on the grass.
• Winter-saturated Willamette Valley clay calls for woven geotextile below the base. The fabric helps keep aggregate from being pushed down into the subgrade through wet seasons.
• Base thickness cannot be replaced with a deeper sand layer. Because sand shifts, this approach can lead to an uneven patio.

Reusing pavers: checking the existing base

For a patio being lifted and reset, first see if the base can remain. Take up the pavers, remove the old bedding sand, and examine the layer below. If it is level, firm, and draining properly, install a fresh 1-inch bedding layer; stone needs drop to a tenth of what a new installation uses. Remove and rebuild the base where there are depressions, soft areas, or pooled water. Leaving those issues in place puts new pavers over the same underlying problem.

Example calculation: a 16 x 12 patio

Start with 192 square feet of paving, then include the 6-inch extension on three exposed sides for a 210 base footprint. At 4 inches after compaction: 210 x 0.333 = 70 cubic feet = 2.6 cubic yards, or about 3.9 tons and 4.3 with the allowance. Purchase 4.5 tons of crusher run and 0.9 tons of bedding sand through the Paver Sand Calculator, in one free delivery. Arrange delivery after the excavation is complete, because stone left on the lawn for two weeks can kill a rectangular patch of grass.

Questions about base depth, excavation and tonnage

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