Question 1

How much crushed stone do I need?

Accepted Answer

Multiply length by width by depth in feet, then by the density of your grade and divide by 2,000 for tons. A 40 × 12 ft driveway at 4 inches of crusher run needs about 10.8 tons.

Question 2

What is crusher run?

Accepted Answer

Crushed stone that still contains its fines — dust and small fragments that fill the voids between larger pieces. That is what lets it compact into a hard, load-bearing base. Washed stone with the fines removed never locks up the same way.

Question 3

What is #57 stone used for?

Accepted Answer

Drainage. It is washed, roughly three-quarter-inch, and has large voids that let water move freely, which makes it right for French drains, behind retaining walls, and under slabs. It is the wrong choice as a driveway base because it stays loose.

Question 4

How much does a yard of crushed stone weigh?

Accepted Answer

Between 2,700 and 3,600 lb depending on grade. Crusher run is heaviest at about 1.8 tons per yard because the fines fill the voids; clean #57 is nearer 1.4.

Question 5

How deep should a crushed stone base be?

Accepted Answer

Four inches under a patio or walkway, six to eight under a residential driveway, and more on clay or soft soil. Depth is set by the sub-grade beneath it — good soil needs less base than poor soil.

Question 6

Do I compact crushed stone in layers?

Accepted Answer

Yes — three to four inch lifts, compacting each. A plate compactor densifies only the top few inches, so a single pass over eight inches of loose stone leaves the bottom half uncompacted, and that is where the settlement comes from.

Question 7

Do I need fabric under crushed stone?

Accepted Answer

On soft or clay soil, yes. A woven geotextile stops the stone punching down into the sub-grade, which is the usual reason a base thins over a few years and the surface starts to move.

Question 8

What is the difference between crushed stone and gravel?

Accepted Answer

Crushed stone is mechanically broken, so the fragments are angular and interlock. Gravel is naturally rounded by water. Angular material makes a base; rounded material rolls, which is why pea gravel drives rut and crushed-stone drives do not.

Crushed Stone Calculator

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