3/8" Crushed Stone in Virginia: Angular, Not Rounded

Two materials on this site measure about 3/8 inch, and buyers mix them up constantly. 3/8" crushed stone is the one with broken faces and sharp corners; Pea Gravel is the one worn round by water. On a Fairfax slope, a Richmond side yard or a lot down on the Eastern Shore where the ground is flat and the rain has nowhere to go, that difference decides whether the surface stays where you rake it.

Sharp faces against rounded ones: what the pile tells you

Tip the two side by side and you can tell them apart across the yard. The crushed chips sit at a steeper angle of repose, so the pile has a peak rather than a slump. Take a handful and the pieces have flat faces and points that catch against your palm. They are gray and buff rather than the mixed tans and creams of the rounded stone, because they came from crushed rock rather than out of a riverbed.

On the ground this shows up in one behavior. Angular pieces wedge against each other and stay wedged; rounded ones roll apart and keep rolling. It is why a crushed chip holds a gentle slope that pea gravel abandons, and why it tracks less on shoes and paws.

What it shares with the rounded stone is size, which means both feel small underfoot and both are easy to move by wheelbarrow.

Beds, paths and a dressing: 3/8" crushed stone on Virginia ground

A landscape or rock garden bed is the common order. At 2 inches over shaped ground it covers evenly, it does not float off in a thunderstorm the way bark does, and on Piedmont clay it lets water through to the graded surface beneath instead of holding it around the plants. Put a separation layer under it so the clay cannot come up through the gaps.

A garden or side-yard path works too, and it is more comfortable than any coarser size because the pieces are small enough not to roll under a foot. Over a compacted base it firms into a proper walking surface. Laid straight onto soft ground it presses in and disappears, which is the usual reason a path like this fails within two seasons.

A splash area under a downspout takes it as well, though with one caveat that the size cannot get around. Concentrated roof water off a steep Northern Virginia roof will push small pieces out of the landing zone. Widen the receiving area, dig it deeper than looks necessary, and contain the downhill edge.

As a driveway dressing it goes over an existing compacted base, never instead of one. It fills the surface voids of the layer below and leaves a finer top course than the base alone gives you.

Where the shed pad goes wrong

A base under a shed or a garage pad is the one to turn down. The material is angular, which helps, but it is a single small size with nothing finer to fill between the pieces, so it will not compact to the density a building corner needs. Settlement shows up as a door that stops closing square.

That pad wants 21A, the dense-graded base graded with fines right through it, placed in lifts and rolled. Once the pad is built and carrying, this stone can go over the top as a dressing if you want the finer look, but it has no structural part in the build.

The same goes for a drive that vehicles turn on. Turning tires scuff a loose small stone sideways and pile it at the edges.

Depth over clay, over sand and over a base

• Landscape and rock garden beds: about 2 inches over a separation layer.
• Paths over a compacted base: about 2 inches of stone, compacted in.
• Downspout splash areas: about 3 inches, carried under the outlet and contained at the low side.
• Driveway dressing over an existing base: about 1 to 1.5 inches. Thicker just gives the tires something loose to push around.
• Pipe and utility bedding: follow the drawing, since the bedding depth belongs to that design.

On flat Coastal Plain ground where water sits near the surface, and on Piedmont clay after a long wet spell, the separation layer matters more than the extra inch of stone.

Yards and tons for a 144 square foot bed, an apron and a pad

Square feet times depth in inches divided by 12 gives cubic feet; divide by 27 for cubic yards. This site's calculator pages put 3/8 inch chips at roughly 2,800 lb per cubic yard, about 1.40 tons.

• Example, a rock garden bed 16 ft by 9 ft at 2 inches: 144 sq ft x 0.167 = 24 cu ft. 24 / 27 = 0.9 cubic yards, roughly 1.2 tons.
• Example, a downspout splash apron 9 ft by 4 ft at 3 inches: 36 sq ft x 0.25 = 9 cu ft. 9 / 27 = 0.3 cubic yards, roughly 0.5 ton.
• Example, a 12 ft by 16 ft shed pad, built the right way with 4 inches of base: 192 sq ft x 0.333 = 64 cu ft. 64 / 27 = 2.4 cubic yards. Dense-graded base runs nearer 3,000 lb per cubic yard on this site's figures, about 1.50 tons, so roughly 3.6 tons of 21A goes into that pad, with none of this stone below the surface.

Run the same numbers through the stone calculator if you want them checked before you order.

Sitting it beside the other small sizes on this site

Choose a quantity and a date on this page once the edges are set and the base is down, so the load lands in finished work. Delivery is arranged at checkout from your ZIP code.