#8 Crushed Stone for Permeable Paving and Drainage in Massachusetts

On a dense town lot where the driveway doubles as the work area, picking between the small stones matters more than the depth you lay them at. #8 crushed stone is graded clean at 3/32 inch to 3/8 inch, with little to no fines in it. Its near neighbor on the same order form, #89, runs 3/8 inch down to fines and is meant to bind. One holds its voids under load. The other closes. That single difference decides most small-stone orders placed here.

Clean at 3/32 to 3/8 inch: what #8 crushed stone will not do

The size band is narrow and the wash is the point. Take a handful and your glove stays clean, which is exactly what you want going into a paver joint or around a pipe.

It will not pack into a firm walking surface. With no fines there is nothing to fill the space between the pieces, so a plate compactor seats the layer and stops there. It will not hold a shape on a steep face either. And it will not carry a structure on its own, which is where half the confusion on this page starts.

Why permeable work in a Massachusetts town waits for the frost to come out

Frost depth here is 48 inches by code, and the ground stays too cold to compact a base through the winter months. Permeable paver work, bedding courses and pipe runs all sit on ground that has to be firm underneath, so the practical season runs from spring thaw through late fall.

Late winter is the worst of it. Dense lower till under most of eastern and central Massachusetts holds snowmelt near the surface, and the subgrade under a half-built pad stays soft for weeks. Starting in March usually means starting twice.

Along the South Coast and on the Cape the ground is deep outwash sand, drains fast and comes back into condition earlier. The frost figure is the same statewide, but the wait is shorter.

Excavation, fabric and a tipping spot, all settled before the load arrives

Three things want to be finished before a clean load goes down.

The excavation comes first, and on till over ledge it may stop shallower than the plan says. Work to the depth the rock allows and adjust the detail above it rather than chasing another six inches.

Geotextile goes between subgrade and stone on anything soft or wet. Till pumps up into open voids under load, and once the spaces are full of silt the layer has stopped doing its job.

Last, decide where the pile goes. On a narrow street the driveway is the only option, so lay a tarp and clear a wheelbarrow route before a date is booked.

Paver joints, drainage courses, pipe beds and a sunny rock garden bank

Four jobs cover most of what leaves on a small clean load.

Permeable paver work is the main one. The stone fills the bedding course and the open joints between units, so rain goes straight down through the surface instead of running to the street.

Drainage layers and French drain runs are the second. The gradation is open enough to move water and small enough to sit tight around perforated pipe without bridging and leaving gaps beneath it.

Concrete batches that call for a finer coarse aggregate are the third.

A rock garden bed on a dry sunny bank is the fourth, and it works better than most buyers expect. Angular 3/8 inch chip stays where it is put on a gentle slope, reads as a finished surface next to planting, and does not float off in a summer downpour the way finer material does.

A culvert outlet is the wrong job, and a shed pad is only half right

Two jobs worth naming plainly.

A culvert outlet is not this stone. Water leaving a pipe in heavy rain has enough force to move 3/8 inch chip in the first storm, and once the apron scours the channel starts cutting in behind it. Outlet aprons want stone heavy enough to stay put, which is RipRap, with #4 Crushed Stone as the step down for a smaller ditch line.

A shed or garage pad is half right. The compacted layer that carries the load is a stone-and-fines blend, so Processed Gravel does that part. Clean stone earns its place as the drainage and leveling course between that base and a slab, keeping water from sitting against the underside of the concrete through a freeze.

A 9 by 12 rock garden and a 10 by 14 shed slab course, in tons

Two hypothetical examples, both worked from the measuring guide on this site: 2 inches for landscaping, 4 inches for driveway and pad depths.

A 9 foot by 12 foot rock garden bed at 3 inches, the depth that covers fabric properly:

• Area: 9 x 12 = 108 square feet
• Depth: 3 / 12 = 0.25 ft
• Volume: 108 x 0.25 = 27 cubic feet
• Cubic yards: 27 / 27 = 1.00

At roughly 2,800 lb per cubic yard, the approximate figure this site publishes for 3/8 inch chip stone, that is about 1.40 tons. Drop to 2 inches and the same bed takes 108 x 0.167 = 18 cubic feet, or 0.67 cubic yards, about 0.94 tons.

A 10 foot by 14 foot shed slab drainage course at 4 inches:

• Area: 10 x 14 = 140 square feet
• Depth: 4 / 12 = 0.333 ft
• Volume: 140 x 0.333 = 46.7 cubic feet
• Cubic yards: 46.7 / 27 = 1.73, about 2.42 tons

With the five percent the stone calculator adds by default it is 1.82 cubic yards, near enough 2.5 tons. Check the figures against the stone calculator before a quantity goes on the order.

Topping joints back up after the first March thaw

Permeable joints settle through the first season and then hold. Sweep a little more in once the frost is out and the surface has dried, and do it before the spring sweeping rather than after.

Beds want less. Blow the leaf litter off in late autumn, because that is what weeds eventually root in, not the stone itself.

Pick a quantity and a delivery date on this page once the arithmetic is settled, or send the measurements through the contact page if the shape is awkward. Delivery is worked out at checkout from your ZIP code, and the driver needs a clear spot he can reach and tip onto. A look at how delivery is arranged is worth five minutes if the street is tight.