Decomposed Granite for Paths, Patios and Hardscape Bedding

The yards this material goes into mostly sit on ground that does one of three unhelpful things. Clay through the Coast Range valleys and the inland basins swells in the wet months and cracks open through the dry ones. Cemented hardpan across parts of the Central Valley stops water a few feet down and holds it. Sandy coastal and desert soils take water instantly and then move underfoot. Decomposed granite is a fine, tight-packing layer, which means it is more sensitive to what is below it than almost anything else sold here, and that is where the planning has to start.

Set beside walkway gravel, mason sand and a clean small stone

Four materials get compared for the same jobs and each one behaves differently in the hand. This one is 1/4 inch minus, mostly stone dust and fine particles with the angular texture of crushed rock. Wet it and roll it and the particles knit into a dense, near-solid surface you can walk a cart or a wheelchair across.

Walkway Gravel is the loose-surface alternative at 3/8 inch. It stays stone underfoot, drains more readily and never tracks into the house, but it will not give you a flat, firm finish and it will not screed level under a flagstone.

Mason Sand is the other bedding candidate. Washed sand screeds beautifully and stays where it is put under a paver, but it has no angular fines to lock the grains, so a unit set in sand can rock if the bedding shifts. DG fills the small voids under an irregular flagstone and firms up around it.

A clean small stone such as #8 Crushed Stone is the opposite choice entirely: open, free-draining and deliberately without fines, which is what a permeable build specifies. If the assembly is meant to pass water through, this material is the wrong layer.

Where decomposed granite earns its place in a low-water yard

The strongest case is a path or patio surface in a yard that has given up its lawn. Watered and compacted, it reads as a warm, quiet ground plane that plants can grow right up to, and it takes a garden cart, a wheelbarrow and a wheelchair without ruts. In a low-water planting scheme that is the difference between a usable yard and a set of stepping stones surrounded by bare dirt.

The second case is bedding and jointing. Under flagstone, brick or pavers the fine material fills the hollows on the underside of each piece so it sits flat, and brushed into the gaps afterwards it packs in and helps hold the units in position. The third is leveling a subgrade before something goes on it, filling shallow low spots so a slab, a deck footing pad or a hot tub platform starts from a true surface.

In all three the layer is a finish or a setting course. The structure, where a structure is needed, is a compacted Class 2 Base underneath it.

Three jobs that will chew it up: a wall backfill, a pond edge, a site entrance

Retaining wall backfill is the first, taking a garden wall as an example. The space behind a wall needs to relieve water pressure, and a fine, tight-packing material does the reverse: it holds water against the back of the wall through every wet month. Clean open stone belongs there, such as 3/4" Drain Rock.

A pond or shoreline edge is the second. Fine material at a water's edge moves. Wave action and the rise and fall of a level lift the particles and carry them into the water, and one winter of storm runoff along the bank finishes the job. That edge wants stone heavy enough to stay, which is RipRap or large cobble.

A construction entrance is the third. The point of a site entrance is that large stone shakes mud off tires before they reach the road, and a 1/4 inch minus surface does the exact opposite: it turns to paste in the wet and picks up on the treads. That job wants a coarse 1 to 2 inch stone instead.

Depth over a base, and why the base decides the result

The site's measuring guide works in finished inches and treats landscape layers at around 2 inches and vehicle areas at 4. For a DG path or patio that lands in the right range: a setting course under flagstone is thinner again, a walked surface sits nearer the landscape figure, and anything carrying weight belongs on a compacted base rather than on a deeper layer of fines.

Depth is not the variable that decides whether the surface survives, though. Fall is. Give the finished surface a consistent slope so storm water crosses it and leaves at an edge, because a flat DG patio on clay will hold water after a big storm and a held puddle is what softens the surface and starts pitting it. Place it slightly damp, compact it in more than one pass, and edge every side. Without an edge the fines walk outwards through the first dry season and the surface thins from the outside in.

Measuring a 70 foot path and a 14 by 16 patio

Take a path as an example, 70 feet long and 4 feet wide, finished at 3 inches. That is 280 square feet. Three inches is a quarter of a foot, so 280 multiplied by 0.25 comes to 70 cubic feet, and 70 divided by 27 is 2.6 cubic yards.

Add the patio it leads to, 14 feet by 16 feet at the same 3 inches. That is 224 square feet, which gives 56 cubic feet, or 2.1 cubic yards. Together the two come to 4.7 cubic yards, and about 4.9 with the 5 percent the stone calculator adds by default for spillage.

You order by the ton, so the stone calculator makes the conversion using the density it holds for this material. Measure the patio twice before committing, because one extra inch across 224 square feet is another 0.7 of a cubic yard. This site publishes about 2,900 lb per cubic yard for screenings, roughly 1.45 tons per yard, which puts the 4.7 yards at approximately 6.8 tons, or about 7.1 with the allowance.

Booking a load into the dry-season calendar

This material wants to go down when the ground is dry enough to compact and the forecast is clear for long enough to finish, which in most of the state means the stretch from late spring into fall. Quantity and a delivery date are both chosen on this page and delivery is arranged at checkout by ZIP code. Think about where a heap of fines can sit without becoming a problem: on a tarp, on a hard surface, out of the line of any sprinkler, and not on the lawn you are keeping. If you are weighing this against another material for the same job and want a second opinion before ordering, ask through the contact page.