Paver Base Materials: Which to Choose

Crusher run is the most common base for pavers. It is also sold as dense-grade aggregate or road base. The product mixes crushed stone with fine stone dust in a graded blend. The mix of sizes is the key feature.

The fines fill the gaps between the larger stones. When you run a plate compactor over the layer, the pieces lock together tightly. The result is a firm, dense base that carries load and holds its shape. This tight packing is why crusher run is the default choice for most patios and walkways.

Crusher run does have a trade-off. The fines hold some water and drain more slowly than clean stone. On ground that stays wet, this can matter. Good grading and a proper slope keep water moving off the base.

Compact crusher run in thin lifts. Spread a few inches, pack it, then add the next lift. A thick single lift will not firm up at the bottom. A weak lower layer lets the surface settle later.

Use the calculator with the crushed-stone density to size a crusher run base. Enter your area and the finished base depth. Add the waste allowance to cover the settling that compaction causes. Crusher run is a dependable, widely available base for foot-traffic surfaces.

Open-graded base uses crushed stone with the fines washed out. It is often sold as clean stone or by a size number. Because there are no fines, the stones leave open voids between them. Those voids are the whole point.

Water passes straight through an open-graded base. This makes it the choice for permeable paver systems and for sites where drainage is a problem. Rain moves down through the stone instead of pooling under the pavers. In cold climates, better drainage lowers the risk of frost heave.

An open-graded system uses a different layering than crusher run. A clean, larger stone forms the base, and a smaller clean stone often serves as the bedding. The whole assembly is designed to drain as one unit. Follow the paver maker's spec for the exact stone sizes.

Clean stone still needs compaction, but it behaves differently than crusher run. It locks up quickly because the angular pieces wedge together. It settles less than a dense-grade base since there are few fines to migrate.

Open-graded base costs more effort to spec correctly. You must match the stone sizes across the layers. When drainage is the priority, it is worth the care. Size it with the crushed-stone density in the calculator, and confirm the exact products with your supplier.

The bedding layer is the thin course the pavers rest on. It sets each paver and lets you level small differences. The material you choose for it is a common point of debate.

Coarse sand, often called concrete sand, is the generally preferred bedding. Its angular, well-graded grains drain freely and stay stable under load. Water passes through instead of sitting against the pavers. The layer holds its shape once screeded, so the surface stays flat.

Stone dust is the main alternative. It is the fine material left from crushing stone. It screeds smooth and packs tight, which some crews like. But stone dust holds water. A wet bedding layer turns soft, and the pavers can settle or rut. For that reason, coarse sand is the safer pick for most patios and walkways.

Avoid fine masonry sand or play sand for bedding. The grains are too rounded and too small. They wash out from between the pavers and let the surface shift.

Keep the bedding layer thin, about 1 inch. Screed it to an even depth over the compacted base. Do not compact the sand before you lay the pavers. Compact after laying, when the joints are filled. Size the sand with its own density in the calculator, separate from the base stone.

Geotextile fabric is a woven or non-woven sheet laid between the soil and the crushed-stone base. It is not a material you measure in tons, but it changes how the base performs. On the right site, it is worth adding.

The fabric separates the base from the soil below. Without it, soft soil can push up into the stone and the stone can sink into the soil. Over time this mixing steals base depth and creates soft spots. The fabric keeps the two layers apart, so the base you built stays the base you have.

Separation matters most on soft, wet, or clay soils. On firm, well-drained ground the benefit is smaller. When soil conditions are poor, the fabric is cheap insurance against a sinking patio.

Some fabrics also spread load and add strength across weak ground. Choose a product rated for base separation, not a thin weed barrier. A light garden fabric will not hold up under a compacted stone base.

Lay the fabric across the compacted subgrade before any stone goes down. Overlap the seams generously and run it up the sides of the dig. Then spread and compact the base on top as usual. If your ground is soft, add a little extra base depth as well, and remember that the calculator sizes the stone, not the fabric.

The same materials serve patios and driveways, but the build changes with the load. Foot traffic and vehicle weight are not the same demand. Match the base to the use before you order.

A patio or walkway carries people and furniture. A 4-to-6-inch compacted crushed-stone base handles this. Four inches suits firm, dry ground. Six inches suits soft or wet soil. A 1-inch bedding sand layer completes the build. This is the standard the calculator defaults describe.

A driveway carries cars and trucks. That load is far higher, so the base must be deeper and well compacted. Plan a thicker crushed-stone base than a patio uses, and compact it in careful lifts. A weak or thin driveway base ruts and cracks under the weight.

Drainage and frost matter more under a driveway. Consider an open-graded base or a geotextile fabric on poor soil. Check your local frost depth, since deeper frost calls for a deeper base. Build a firm edge restraint to hold the field against the push of vehicle traffic.

Set your layer depths for the true use, then let the calculator size the tons. Enter the base and bedding depths as separate layers. Keep the waste allowance on to cover compaction. Order slightly long, because a stalled job costs more than a small surplus of stone.