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Gravel & Aggregate

How much stone a job takes — in tons, which is how quarries actually sell it, with the compaction allowance that separates a base course from a decorative bed.

Stone is sold by the ton. Every calculator that stops at cubic yards has stopped one step short of the number you will be billed for.

The conversion is different for every material, because they weigh different amounts per yard: #57 crushed stone 2,700 lb, crusher run 2,800, pea gravel 2,700, river rock 2,600, masonry sand 2,700. Those are dry, loose figures — wet stone runs up to 10% heavier, and the quarry weighs it wet.

Compaction is a property of the material, not of the job

Crusher run and other base materials lose roughly a fifth of their volume under a plate compactor. Order the finished volume and you will be short by exactly that, on the day, with the compactor already on hire.

Decorative stone is never compacted. Adding a base-course allowance to river rock is the same mistake pointing the other way — a pile you cannot use.

Depth by use

2″ for decorative beds. 3″ for walkways. 4″ for a pedestrian paver base or drainage. 6″ under vehicles. 8″ on soft or filled ground.

Getting the depth right matters more than getting the material right. A driveway base at 3 inches fails whatever stone is in it.

Delivery is priced by the load

Not by the ton. Ordering short and needing one more delivery usually costs more in fees than the extra stone would have cost outright. Round up.

Compact in lifts

No more than four inches at a time. A single pass over eight inches of loose stone compacts the top few inches and leaves everything below it exactly as loose as it was — which is where the settlement comes from two winters later.

1 article

How much pea gravel for a 22 × 22 ft area, 4″ deep?

pea gravel
8.07tons
5.98 yd³ for 484 ft² at 4″
Plan22 ft22 ft484 ft²SectionStone — 4″
Order this many tons8.07tons
Volume161 ft³5.98yd³
Area22 × 22 ft484ft²
50 lb bagsfar cheaper to have it delivered loose323bags
Coverage per ton60ft² at 4″
Weight assumeddry and loose — wet stone runs up to 10% heavier2700lb/yd³
Typical usepaths and play areas — rounded, so it moves underfoot

Notes

  • Stone is sold by the ton, not by the yard. That conversion is where estimates go wrong, and it is different for every material: pea gravel runs 2700 lb per cubic yard, so 5.98 yd³ is 8.07 tons. Quarries quote and bill in tons; the yardage figure is only useful for picturing the pile.
  • No compaction allowance here — pea gravel is not compacted in normal use. Adding a base-course allowance to decorative stone is the mirror-image mistake to leaving it off crusher run.
  • 4″ is about right for paver base (pedestrian) and drainage. For reference: 2″ for decorative beds, 3″ for walkways, 4″ for a pedestrian paver base or drainage, 6″ under vehicles, 8″ on soft soil.
  • Get the depth right before the material. A driveway base at 3″ fails no matter how good the stone is, and a decorative bed at 6″ is money buried where nobody sees it.
  • Delivery is priced by the load, not by the ton. Ordering 8.07 tons and then finding you need one more usually costs a second delivery fee larger than the extra stone — round up.

Gravel and aggregate

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