Exposed aggregate driveways look great -- but they're easy to damage if you pressure wash them wrong. Too much PSI and you'll start popping stones right out of the surface. The good news: with the right settings and technique, you can get an exposed aggregate driveway clean without any damage.

The Quick Answer

Exposed aggregate needs lower pressure than standard concrete. Here's what the pros use:

PSI range: 2,100 to 3,000 PSI (never above 3,000)
Nozzle: 40-degree (white tip) for rinsing; 15-degree for spot scrubbing
Distance: 12 to 18 inches from the surface
Detergent dwell: 2 to 3 minutes before rinsing
Pricing: $0.35 to $0.77 per sq ft (vs. $0.10 to $0.20 for standard concrete)

Exposed aggregate is a specialty service. It's worth charging more because it takes extra care, technique, and time.

Why Exposed Aggregate Needs Special Treatment

Standard concrete is one solid slab. Exposed aggregate is different -- it's a mix of concrete and decorative stones (pebbles, gravel, glass, or shells) where the top layer of cement has been removed to expose those stones.

That's what makes it beautiful. It's also what makes it tricky to clean. The stones sit partially embedded in the concrete, and high-pressure water can loosen them and pop them right out. Once a stone's gone, there's no putting it back.

The rule: use the minimum pressure needed to do the job. Start low and work your way up only if necessary.

Step-by-Step Technique

Step 1: Pre-Wet the Surface

Start at around 1,500 PSI with a wide nozzle and wet the entire driveway. This loosens surface grime and prevents your machine from pulling dust into the pump. It also gives you a read on how the surface responds before you increase the pressure.

Step 2: Apply Detergent

Switch to a detergent-compatible nozzle (usually black tip) and apply a concrete cleaner at a 1:10 dilution ratio. A concrete degreaser works well for tire marks and oil stains. Let it dwell for 2 to 3 minutes -- the chemical does most of the cleaning work so your pressure washer doesn't have to.

Don't let the detergent dry. On hot days, work in smaller sections to keep the surface wet.

Step 3: Rinse at the Right PSI

Increase to 2,500 to 3,000 PSI using a 40-degree nozzle and rinse in overlapping passes. Keep the wand 12 to 18 inches from the surface. Point the spray slightly away from edges to avoid undercutting the border stones.

Move in sweeping left-to-right passes, then go over the same area top-to-bottom. This cross-pattern technique cuts streaking and lifts embedded grime better than single-direction passes.

Step 4: Spot-Treat Stubborn Stains

For oil stains or dark spots that didn't lift, switch to a 15-degree nozzle -- but be careful. A narrow tip at 3,000 PSI can dislodge aggregate if you hold it too close. Keep it at least 10 to 12 inches away and use short bursts.

For really stubborn oil, apply a second round of degreaser, scrub with a stiff brush, and rinse again rather than cranking up the pressure.

Which Nozzle to Use

Nozzle choice matters more on aggregate than on standard concrete. Here's the breakdown:

Black tip (soap nozzle): Detergent application only -- very low pressure
40-degree white tip: Main rinsing nozzle -- safest for aggregate surfaces
25-degree green tip: OK for the first pass on heavily soiled areas
15-degree yellow tip: Spot cleaning only -- use with caution, keep distance
0-degree red tip: Never use on exposed aggregate -- too much concentrated force

How to Price Exposed Aggregate Jobs

This isn't a standard concrete job. Charge accordingly.

Standard concrete driveways run $0.10 to $0.20 per sq ft. Exposed aggregate should be priced at $0.35 to $0.77 per sq ft because of the extra care and technique involved. A 500 sq ft driveway at $0.50/sq ft = $250.

Set a minimum of $175 to $200 for any aggregate job. Drive time and setup cost the same regardless of size.

Upsell opportunity: exposed aggregate benefits from sealing every 2 to 3 years after a good cleaning. Offer a penetrating sealer application for an extra $0.10 to $0.25/sq ft. It's a quick add-on that boosts most jobs by $50 to $125.

Common Mistakes to Avoid

Too much pressure: Anything over 3,000 PSI risks dislodging stones permanently.
Getting too close: Keep 12 to 18 inches of distance. Closer is not better on aggregate.
Skipping detergent: Chemical dwell time does the heavy lifting. Pressure alone won't lift embedded oil stains.
Using a 0-degree tip: That's for stripping paint off concrete, not cleaning decorative aggregate.
Pricing it like standard concrete: This job takes more care and skill. It should cost more.

Bottom Line

Exposed aggregate driveways are a premium specialty that most pressure washers get wrong by using too much pressure or the wrong nozzle. Get the technique right -- 2,500 to 3,000 PSI, 40-degree nozzle, 12 to 18 inches of distance, detergent dwell -- and you can clean these surfaces without damage while charging a premium rate for the expertise.

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How to Pressure Wash Exposed Aggregate Driveways (2026 Guide)