#57 Stone in Virginia: the Washed Size for Drainage and Pads

Nearly every order placed for this stone starts with one unspoken decision: does this layer need to move water, or does it need to stay put under weight? On ground that swings from tidal sand around Hampton Roads to slow red clay through the Piedmont to rock close to the surface out past the Blue Ridge, that question has different answers on different lots, sometimes on the same lot. #57 stone is the washed size that answers the first half of it, and it is a poor substitute for the second.

Am I moving water, or am I carrying a load?

Work through it in that order and the material choice falls out on its own.

• Water has to move through the layer: a French drain, a curtain drain, backfill behind a retaining wall, a downspout run. This stone, with the fines washed out and the voids left open.
• Weight has to sit on the layer without settling: a drive, a parking pad, a lane. A dense-graded base such as 21A that packs hard.
• Both, in sequence: the base carries, a drain line underneath moves the water, and the two layers are separated so they stay doing their own jobs.

Size here is 3/16 inch to 1 inch, graded to the #57 designation, angular crushed rock. Locally that number comes from the VDOT washed stone sizes, which is how yards and plans across the state describe the material rather than a certification this storefront holds.

Will #57 stone hold up under a hot tub pad on Piedmont clay?

It will, with the layers in the right order. An 8 ft by 8 ft tub full of water and people is a concentrated, static load on ground that drains slowly and swells when it wets.

• Strip the organic layer and get onto firm subgrade. Soft ground under a corner is what tips a tub, not the stone above it.
• Compact a dense-graded base first. That is what carries.
• Use the washed stone as the free-draining layer where the design calls for one, and keep it separated from the clay so fines cannot migrate up into the voids.
• Give the whole pad a fall away from the house. Slow-draining clay holds whatever you leave sitting on it.

Where the tub manufacturer or an engineer specifies a slab or a particular build-up, follow that, because the stone is part of somebody else's design at that point.

Can a side-yard dog run be surfaced with it?

Yes, and it is one of the better uses for a narrow side yard that never dries out. It drains after a thunderstorm instead of turning to a mud strip, it rinses clean with a hose, and the angular faces hold together better underfoot than rounded stone.

Two cautions. Loose washed stone at 3/4 inch is uneven to walk on in soft shoes, so it suits the dog more than it suits you. And it will travel out of the run unless you contain it: an edge board, a paver curb, or a trench edge cut below the surrounding grade.

What happens to a turnaround pad when the ground stays wet?

This is where the coastal lots and the low Piedmont bottoms part company from everywhere else.

• On flat Coastal Plain ground through Hampton Roads, the Eastern Shore and the river necks, water sits close to the surface and has nowhere to run. Open stone dropped straight onto saturated ground is pressed into it and disappears, so separation is not optional there.
• On Piedmont clay the stone stays on top for a while and then sinks in ruts where the tires track, for the same reason.
• West of the Blue Ridge, in the limestone valleys, the concern turns the other way: concentrated runoff into karst ground goes down into the rock, so a pad that channels water into one spot is worth rethinking.

A turnaround that sees regular vehicle movement is better built as a compacted base with a wearing course, keeping the washed stone for the drainage part of the job.

How many cubic yards does a 12 by 14 foot pad take?

Length by width in feet, times depth in inches divided by 12, divided by 27 for cubic yards.

• Example, a turnaround or parking pad 12 ft by 14 ft at 4 inches: 168 square feet x 0.333 = 56 cubic feet. 56 / 27 = 2.1 cubic yards.
• Example, an 8 ft by 8 ft hot tub pad at 4 inches: 64 square feet x 0.333 = 21.3 cubic feet. 21.3 / 27 = 0.8 cubic yards.
• Example, a dog run 6 ft wide and 30 ft long at 3 inches: 180 square feet x 0.25 = 45 cubic feet. 45 / 27 = 1.7 cubic yards.

This site publishes roughly 2,800 lb per cubic yard for #57 stone, about 1.40 tons per yard, and that weight is approximate: the 12 by 14 pad above is 2.1 x 1.40 = roughly 2.9 tons, with the hot tub pad about 1.1 tons and the dog run about 2.4 tons.

An open-graded stone does not tighten down the way a dense base does, so what lands is close to what you end up looking at. Feed the cubic yards into the stone calculator to convert them to tons for this material.

Which washed size should actually be on the order?

Four products on this site look similar in a photograph and behave differently in a trench.

Order by the name printed on the plan. If a drawing calls out a number, the number is the order.

Choose your quantity and a delivery date on this page. Delivery is arranged at checkout from your ZIP code, so pick a tipping spot a loaded truck can reach before you book.