Gravel Driveway

The situation

You want a driveway you can park on that does not turn to mud, does not wash out in an afternoon storm, and does not cost what concrete costs.

Almost everyone starts by searching for "gravel". That instinct is half right, and the half that is wrong is the reason a lot of gravel driveways fail within a year.

What to buy

You want a material that compacts, not one that stays loose. That is the whole decision.

Loose washed stone — #57 rock, pea rock, anything rounded and clean — has no fines in it. Nothing binds the pieces together, so tyres push it sideways. Within a few months you have ruts down the middle and berms along the edges, and you are raking it back every weekend.

What you actually want is a material with a full range of particle sizes, from coarse down to powder. The fines fill the gaps and, once watered and compacted, the whole layer locks into something firm.

The two good options

Crushed concrete is the usual answer. It is recycled concrete crushed to a driveway gradation, it compacts hard, and it actually keeps getting harder over the following months as leftover cement in the mix rehydrates. It is also the cheapest of the compactable materials.

Shell rock is the other. It compacts nearly as well and cures out a light buff colour rather than grey, which a lot of people prefer in front of a house. Slightly softer than crushed concrete.

If you want a dark, paved-looking surface, put 2 to 3 inches of asphalt millings on top of a compacted base of either. Laid in summer heat and rolled, millings bind into a firm dark surface that barely dusts.

How much you need

Four inches of compacted material is the minimum for a car. Six is better, and six is what you want if a truck or an RV ever parks on it.

One cubic yard covers roughly 80 square feet at 4 inches deep, or 55 square feet at 6 inches. So:

• A single-car drive, say 10 by 40 feet (400 sq ft), at 4 inches — about 5 yards
• A two-car drive, say 20 by 30 feet (600 sq ft), at 4 inches — about 8 yards
• The same two-car drive at 6 inches — about 11 yards

Add roughly 20 percent on top of those figures, because compactable material shrinks as you roll it. Our calculator adds that allowance for you.

Not sure? Tell us the rough size of the area and how deep you want it and we will work it out with you. Nobody expects you to know this — it is our job, not yours. Or use the calculator.

How to do it

1. Strip the grass and topsoil. Building on soft organic soil is why driveways sink. Get down to firm ground.
2. Grade it to shed water. A slight crown or fall to one side. Water sitting on a driveway is what destroys it.
3. Spread in layers, not all at once. Three inches at a time, maximum.
4. Wet each layer and compact it before adding the next. Damp, not soaked. A plate compactor from a rental yard is fine for a residential drive; a roller is better.
5. Top up after the first season. Some settling in the wheel tracks is normal, not a failure.

If you skip the compaction step, none of the rest matters. That is the single most common DIY mistake on this job.

Materials for this job

Gravel Driveway — common questions

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