How to Clean & Maintain Exposed Aggregate Concrete

Exposed aggregate is one of the toughest, best-looking driveway and path finishes you can lay — but like any surface, it looks its best when it’s cleaned and sealed on a sensible schedule. The good news is that maintenance is simple, cheap and only needed a few times a year. Here’s how to keep exposed aggregate concrete looking like the day it was poured.

Think of upkeep in three tiers: quick routine cleaning every few months, a deeper clean once or twice a year, and resealing every few years. Get those three rhythms right and the surface effectively looks after itself. Skip them for years on end and you don’t ruin the driveway — the strength is in the slab, not the surface — but you do let stains set, the colour go flat and the sealer wear thin, which means more work to bring it back later. A little and often always beats a big rescue job.

What you’ll need

None of this calls for special gear. A basic kit covers almost everything:

• A stiff-bristled outdoor broom (not a soft indoor one)
• A bucket, plus dishwashing liquid or a dedicated pH-neutral concrete cleaner
• A garden hose with a decent nozzle
• Optionally, a domestic pressure washer for the deeper cleans
• For stains: an absorbent (cat litter or bicarb), a degreaser, and an oxygen-bleach or mould cleaner

Avoid strong acids, wire brushes and pinpoint high-pressure jets — all three can etch the paste, dull the stone or strip the sealer. Gentler is almost always better on a decorative finish.

Routine cleaning (a few times a year)

Most of the time, exposed aggregate only needs a basic clean two or three times a year:

1. Sweep first. Clear leaves, dirt and grit with a stiff outdoor broom. Left sitting, organic matter stains the surface and feeds mould.
2. Wash with warm water and a mild detergent. A squirt of dishwashing liquid or a dedicated concrete cleaner in a bucket of warm water is plenty. Avoid harsh acids, which can etch the surface and dull the stone.
3. Scrub with a stiff broom. Work the solution into the texture — the exposed stone traps a little more grime than a smooth surface, so agitation matters.
4. Rinse thoroughly with a garden hose so no detergent residue is left behind.

That’s it for everyday upkeep. Doing this in spring and again in autumn keeps most driveways looking fresh.

Pressure washing exposed aggregate

A pressure washer is the fastest way to lift ground-in dirt, algae and general weathering once or twice a year. Used correctly it’s completely safe on exposed aggregate:

• Keep the nozzle at least 20–30 cm from the surface and use a wide fan tip, not a pinpoint jet.
• Use a moderate pressure setting — you’re cleaning the surface, not blasting the stone or sealer off it.
• Keep the wand moving in even, overlapping passes.

If your driveway is sealed (it should be — more on that below), a heavy-handed pressure wash can wear the sealer over time, which is another reason to keep the pressure sensible and reseal periodically. As a rule of thumb, if the water is stripping visible flecks of sealer or leaving a lighter “cleaned” stripe that stands out sharply, you’re too close or too high on pressure. Back off and let the detergent do more of the work.

Removing common stains

• Oil and grease: Blot fresh spills immediately. For set-in stains, sprinkle an absorbent like cat litter or bicarb, leave it, sweep it up, then wash with a degreaser. A good sealer makes this far easier because the oil sits on top instead of soaking in.
• Tyre marks and rust: A dedicated concrete cleaner usually shifts these. Avoid strong acids.
• Mould, moss and algae: Common in shaded, damp spots. A diluted oxygen-bleach or a specific mould cleaner, scrubbed in and rinsed, does the job. Improving drainage and trimming overhanging plants helps stop it coming back — the same drainage thinking that stops concrete cracking.
• Leaf and tannin stains: Fallen leaves, gum nuts and bark left sitting in damp weather leach tannins that stain the surface a reddish-brown. Sweep debris off promptly and the problem never starts; for existing marks, an oxygen-bleach solution usually lifts them.
• Efflorescence (white haze): A powdery white bloom that can appear on newer concrete as mineral salts migrate to the surface. It’s cosmetic and usually weathers off, or a dedicated efflorescence remover clears it. Don’t attack it with strong acid.

Mistakes that damage exposed aggregate

Most driveways that look tired before their time have been cleaned the wrong way, not too little. Steer clear of these:

• Strong acids and hydrochloric (“brick”) acid. They etch the cement paste, dull the exposed stone and strip sealer. There’s almost never a reason to use them on a decorative finish.
• Pinpoint pressure-washer tips held close. A zero-degree jet can gouge the paste from around the stones and leave permanent tracks. Always use a wide fan tip and keep your distance.
• Wire brushes and metal scrapers. They scratch the surface and can leave rust marks. A stiff synthetic broom is all you need.
• Sealing over a dirty or damp surface. Trapped grime and moisture cause the new coat to cloud, peel or fail to bond. Clean, then let it dry fully first.
• Letting spills sit. Oil, tannins and rust are all far easier to remove fresh than set-in. A quick response beats any product.

Does concrete need to be sealed?

Yes — exposed aggregate should be sealed, and it makes a real difference. Sealing:

• Brings out the colour of the stone, giving that rich, “wet look” finish.
• Repels water, oil and stains so spills wipe up instead of soaking in.
• Protects against weathering and surface wear, extending the life of the finish.
• Makes routine cleaning easier, because dirt sits on the surface.

Sealing is normally included in a good exposed aggregate quote when the driveway is first laid, so your new surface arrives already protected.

Plain broom-finished concrete doesn’t strictly need sealing to survive, but sealing it still helps resist stains and dusting — it’s optional there, and recommended for decorative finishes.

How often should you reseal?

For exposed aggregate in a typical Australian driveway, plan to reseal every 2–4 years. The exact interval depends on:

• Traffic and wear — a busy driveway wears faster than a quiet path.
• Sun exposure — full-sun areas break down sealer faster.
• The sealer used — some premium sealers last longer between coats.

An easy test: flick some water onto the surface. If it beads up, the seal is still working. If it soaks straight in and darkens the concrete, it’s time to reseal. Resealing is a low-cost job — far cheaper than repairing a neglected, stained surface — and it’s the single best thing you can do to keep the finish looking new.

Always clean the surface thoroughly and let it dry before resealing, and follow the product’s guidance on coats and drying time. If you’d rather not do it yourself, it’s a quick job for a concreter.

Doing it yourself vs calling a concreter

Routine cleaning is firmly a DIY job — sweeping, washing and the occasional gentle pressure wash need no special skill. Resealing sits on the fence. A confident homeowner can reseal a driveway with a roller or sprayer on a dry, mild day, provided the surface is spotless and completely dry and the product is applied thinly and evenly. The common DIY pitfalls are applying too much (which leaves a cloudy, sticky film), sealing in the heat of the day, or sealing over trapped moisture after rain.

Where it’s worth calling in a concreter is when the surface is badly weathered, the old sealer is patchy and peeling, or the finish has never been sealed and you’re not sure what you’re working with. A professional reseal includes proper cleaning, the right sealer for the exposure, and even coverage — and if the surface is genuinely worn or damaged, resurfacing or repair may be a better call than another coat of sealer over a failing finish.

Local care around the Limestone Coast

A few regional conditions change how often you’ll be out with the broom and the sealer:

• Coastal salt at Port MacDonnell, Beachport, Robe and Kingston SE is abrasive and drying. Driveways near the coast benefit from more frequent rinsing to wash salt off, and from staying on top of resealing so the surface stays protected.
• Shade and damp in the cooler, wetter months feed moss and algae, especially on south-facing paths and under trees. A once-a-year mould treatment and good drainage keep it in check.
• Leaf litter from established gums and deciduous trees inland is the main staining culprit — sweeping little and often does more than any cleaner.
• Reactive terra rossa soils inland move with moisture. That’s a base and drainage issue rather than a cleaning one, but keeping water flowing away from the slab protects both the surface and the ground beneath it.

None of this is onerous — it’s mostly about timing your regular clean to suit where you live.

A simple maintenance schedule

When	Task
Every few months	Sweep; wash with warm water and mild detergent
Once or twice a year	Gentle pressure wash; treat any mould or stains
Every 2–4 years	Reseal (or when water stops beading)

Stick to that and exposed aggregate will stay looking sharp for decades. For a fuller picture of what the finish costs and how it compares to other options, see our exposed aggregate cost guide, and if you’re still choosing a surface, our concrete vs pavers for a driveway comparison shows just how much less maintenance a seamless slab needs.

Common questions

How often should I clean exposed aggregate? A quick sweep and wash two or three times a year covers most driveways, with a deeper clean once or twice a year. Coastal and heavily shaded surfaces may want a little more.

Can I use a pressure washer? Yes, safely — keep a wide fan tip 20–30 cm from the surface at moderate pressure, and keep moving. Avoid pinpoint jets held close, which can gouge the paste and strip sealer.

How do I know when to reseal? Flick water onto the surface. If it beads, the seal is fine. If it soaks in and darkens the concrete, it’s time. For most driveways that’s every 2–4 years.

Does exposed aggregate have to be sealed? It should be. Sealing brings out the colour, repels stains and makes cleaning far easier. It’s normally included when the driveway is first laid.

Can I fix a stain that’s already set in? Usually. Oil responds to an absorbent then a degreaser; mould and tannins to oxygen-bleach; rust to a dedicated concrete cleaner. Avoid strong acids on any of them.

Need your driveway resealed or restored?

If your exposed aggregate has lost its shine or you’ve inherited a tired, unsealed surface, we can clean, reseal or resurface it and get it looking new again.

Want your driveway looking its best? Call 0400 123 456 or get a free quote for exposed aggregate concrete — across Mount Gambier and the Limestone Coast.