Gravel Delivery FAQ for California Drives and Hillside Lots

Phoning round yards for a quote and ordering online differ in one way that matters: online, nobody asks what the job is. You pick the grade, the depth and the tonnage yourself, and the load arrives exactly as specified. The questions that choice raises are collected below, and they matter more in this state than in most, because ground here spends half the year hard and dry and then takes a large share of its annual rain in a few winter storms.

Holding a drive together on a foothill grade

My drive runs down a foothill slope. How do I stop the gravel migrating to the bottom?

Compaction does most of the work. A properly rolled base behaves as one mass rather than as loose stone, so start there rather than with more depth. Beyond that, give the surface a crown or a cross-slope so storm water leaves sideways instead of running the length of the drive, hold the downhill edge with a header board, a concrete lip or a row of larger stone, and give runoff coming off the slope above its own route so it never reaches the drive. An angular graded material stays put far better on a grade than rounded pea gravel or cobble, which roll.

Fines and depth: the two things that move the number

How do I tell clean drain rock from a material that carries fines?

Read the grading line on the product page. Washed or clean material, such as Drain Rock or the #57 grading, has had the dust and small particles removed, so water travels through the gaps. A graded mix described with fines, dust or a minus size, such as Class 2 Base or crusher run, is built to compact. Put the compacting one in a drain and it will silt that trench closed inside a couple of wet seasons.

A daily car, or a trailer and a mini excavator: how much base?

Four inches compacted is the usual starting point for car traffic on ground that is already firm. A lane carrying loaded trucks, trailers or equipment wants a thicker section placed in lifts, and so does anything built on the shrink-swell clay common through the Coast Range valleys and the southern basins. Once the loads get serious it becomes an engineering question, so settle it with the building department or whoever designed the drive.

Leftovers, local names and jobs that need two layers

Is leftover Class 2 base worth keeping through the winter?

Usually, yes. Base rock keeps indefinitely under a tarp on a spot that drains, and after the first heavy storms there is generally a washout, a rut or a soft patch at a gate that it will patch. Leftover clean drainage stone is worth keeping for the same reason. Decorative cobble and pea gravel are less useful in reserve, so those are worth measuring tightly.

My contractor said base rock and the catalogue says something else. Which do I order?

Both, usually. The base product here is listed as Class 2 Base, which is the name the local specification uses, and base rock, Class II base and recycled base rock are all names for the same job. The safe check is not the name but the numbers: compare the size and grading printed on the product page with the words on your plan or quote sheet. Path fines quoted as DG are Decomposed Granite, and clean drainage stone quoted as 3/4 drain rock is 3/4" Drain Rock.

How do I plan a drive that needs a base and a surface course?

As two orders on one delivery. Work out the base first, at its compacted thickness, then the wearing course separately, because the depths differ and so do the weights per cubic yard. Class 2 base underneath, Driveway Gravel or decomposed granite on top. Add both to the same order, and mark two separate spots on the ground so the piles do not blend into each other.

Storm-soft ground, and rebuilding a drive from the subgrade

The site is still soft from the last storm. Should I take the delivery?

Give it a few dry days if the approach is unsurfaced. Clay and the flat hardpan ground on parts of the valley floor hold water at the surface rather than letting it soak away, and a loaded truck will rut an approach that carried a car the week before. Rescheduling a date costs nothing compared with repairing a lawn or a soft drive shoulder.

Rebuilding a drive from the subgrade up: which layer first?

Strip the soft or organic material off the subgrade and grade it so water leaves. Compacted Class 2 base next, placed in lifts rather than one thick layer, at a thickness set by the traffic and the ground beneath. Then the wearing course you look at: driveway gravel, decomposed granite, pavers on bedding sand, or a slab. Drainage is designed in at the start, not added afterwards, since the layer that cannot shed water fails long before it is overloaded.

Work out quantities with the material calculators, which also settle rounding, an awkward shape and the ton-against-yard question, then choose the amount and a date on the product page. Truck room, the tip, the checkout fields and what happens once an order is in are all on the delivery page. If the job swallows more than you bought, buy the extra on its own rather than trying to grow an order that already has a date against it. The refund and order-change policy is published there.

Who operates California Rock Supply?