Gravel Delivery FAQ: Ordering, Access and Red Clay

Two kinds of ground set most of the questions on this page. North of the Fall Line the subsoil is red clay over weathered granite and gneiss, which sheds a thunderstorm off a slope and then holds whatever soaks in. South of it the Coastal Plain is sandy, flat and drained by a high water table rather than by runoff. The questions below start with the mistakes those two grounds cause, then work through choosing and layering the material.

Keeping stone where you put it on a Georgia slope

Our drive falls away toward the creek. How do we keep the stone from ending up at the bottom?

Angular stone holds a slope far better than rounded stone, so a compacted base of crusher run or graded aggregate base with an angular surface over it stays put where pea gravel or river rock would creep downhill. Give the surface somewhere to shed to, because water running down the length of a drive is what moves the material. Where the slope is a bank rather than a drive, the answer is armor: fabric first, which is not a catalogue item here and comes from a local landscape supplier, then RipRap placed in layers of 12 inches or more. Larger stone at the bends of a dry creek bed does the same job on a smaller scale.

Clean stone against material with fines, and how thick to build

Clean stone or crusher run: what actually separates them?

Whether the fines were washed out. Clean stone, such as #57 Granite or Drain Rock, has the dust removed, so the gaps between pieces stay open and water travels through. Material with fines, such as crusher run at 3/4 inch minus or GAB (Graded Aggregate Base) at 1 inch minus, carries stone dust all the way through the mix; under a compactor those fines wedge into the gaps and the layer locks up. One drains and will not hold still. The other holds still and will not drain. Almost every wasted order on a clay lot comes from swapping them.

How deep does a base go for a family car, against something that carries a loaded truck?

The figures this site publishes for typical work are 4 inches of compacted crusher run or road base, with 2 to 4 inches of driveway gravel over the top, or about 6 inches of gravel on a new drive that is starting from bare ground. That covers normal car and light van traffic on ground that is firm.

Regular loaded-truck traffic is a different question and a catalogue depth cannot settle it. Loads, subgrade strength and drainage all come into it, and the sensible route is a contractor or an engineer who can look at the subgrade. What is safe to say is that on wet Piedmont clay more thickness alone does not fix a soft subgrade; excavating the soft material and laying geotextile fabric under the base does far more.

Is leftover material worth hanging on to?

Stone and gravel, yes. It does not spoil, and a spare half yard of the same product is worth keeping for the settling that shows up in the first wet season, particularly on clay. Pull it to one side on a tarp so it does not sink into the ground or get contaminated with soil.

Soils and mulch are less worth storing. Topsoil and garden soil compact and go anaerobic in a heap, and mulch breaks down. Better to plan those to the area you are actually covering and spread the lot.

Local names, two-layer jobs and clay that is still wet

I was told to get GAB, or surge stone, or M10. Which product is that here?

Georgia names and catalogue labels do not always match, so here are the common ones. GAB, or graded aggregate base, is listed as GAB (Graded Aggregate Base). Crush and run is Crusher Run. M10, granite dust and granite screenings all mean Screenings. #57 granite and 57 stone are #57 Granite. Surge stone is the local name for the large granite used to line creeks and culvert ends, which is stocked here as RipRap. River slicks are the big smooth stones for dry creek beds and bed edging, listed as Large River Rock. Pea pebbles are 3/8" Natural Pea Gravel. If a spec sheet uses a GDOT size number, compare it against the size and grading printed on each product page.

The job needs a base and a surface. How do I order that?

As two products and two calculations, never as one deep number. Work out the base layer at its own thickness, then the surface layer at its own, and enter each into the calculator separately. A drive is commonly a compacted crusher run or GAB base with Driveway Gravel or #57 over it. A paver patio is a compacted base with a 1 inch bedding layer of screenings or sand above it, and the Paver Base and Paver Sand tools exist precisely so those two are sized apart.

The ground is still soft from a wet week. Do we go ahead?

Not with base work. Material compacted onto saturated red clay floats on something soft and ruts under the first real load, and a heavy truck crossing soft ground leaves damage of its own. Wait the wet spell out where you can. Where the ground stays soft regardless, which happens in flat Coastal Plain low spots and in a Piedmont hollow with a downspout running into it, the fix is not extra stone. Dig the soft material out, lay geotextile fabric from a landscape supplier, put coarse stone in, and build the base on that. If the delivery date is already set and the ground has turned, drop the pile on the drive and move it when the ground firms up.

Building a drive up from bare red clay

Starting on bare red clay, which layers go down, and in which sequence?

The usual sequence on red clay runs like this. Strip the turf and soft topsoil and cut to grade, because organic material under a drive breaks down and the surface settles unevenly. Where the subgrade is soft, excavate it and lay geotextile fabric. Build the base in lifts of a few inches, compacting each one, using crusher run or graded aggregate base, keeping the material slightly damp so the fines bind. Shape the surface with a little fall so a summer downpour runs off rather than standing. Then place the surface layer, driveway gravel or #57 granite, and compact it. Run each layer through the calculator on its own before ordering.

Two things people ask here are answered better a click away. Units, rounding and the tonnage behind a given volume come out of the material calculators, which hold each product's own weight. The order form, the wooded lane and the pile itself are the delivery page's business, and so is a job that runs long: the extra goes on its own order rather than into the booked one. The refund and order-change policy is published beside it.

What is the difference between clean stone and material with fines?

Who operates Georgia Rock Supply?