Exposed Aggregate Concrete: Why Adelaide Chose It, and How to Get It Right

Drive any new Adelaide subdivision and count the driveways: exposed aggregate has quietly become the city's default premium surface. It earned that position honestly — it hides tyre marks and dust that plain grey advertises, it grips underfoot when wet, and it reads as a designed finish rather than infrastructure.

What it costs

Installed exposed aggregate in Adelaide currently runs $130–$180 per m², against $95–$130 for plain grey — the premium buys a decorative mix (the stone is specified, not whatever's in the plant that day), more finishing labour, and the wash-off process itself. Small pours sit at the top of the range because establishment costs don't shrink with area.

How the finish actually happens

Exposed aggregate isn't stone glued onto concrete — the decorative stone is in the mix. The slab is placed, screeded and floated conventionally; a surface retarder is sprayed on; and at precisely the right cure window (hours, and weather-dependent — this is the skill), the top millimetres of cement paste are pressure-washed away, revealing the stone beneath. Timing the wash-off is everything: too early scours deep and dislodges stone, too late and the paste has set over it. It's the least forgiving finishing process in domestic concreting, which is why experience is most of what you're paying for.

Choosing a blend

Adelaide suppliers offer dozens of regional blends — warm river pebbles, charcoal basalts, creamy quartz mixes. Three practical rules: view a sealed sample (sealing deepens colour dramatically, and the wet look is the look you'll live with); match undertones to your roof and render rather than chasing the stone in isolation; and for driveways choose blends with 7–10 mm stone — bigger feature pebbles look spectacular but shed more readily under turning wheels.

The details that separate good from average

Everything from our plain concrete playbook still applies underneath: compacted base, correctly positioned mesh, saw-cut control joints (cut cleanly through the decorative surface — crisp joints are a signature of good work). Then add: consistent wash-off depth across pours done on different days, matched batching so panel colours agree, and edges tooled before wash-off so margins stay sharp.

Sealing: the maintenance truth

Seal at completion, again around 12 months, then every 2–4 years depending on sun and traffic. Sealed aggregate resists oil, tannin stains from overhanging trees, and UV dulling; unsealed, the cement matrix slowly erodes and stones begin to pluck at the surface. It's an hour with a roller every few years to keep a 30-year surface — take the deal.

Thinking exposed aggregate for a driveway, alfresco or pool surround? See how we build it.