Exposed Aggregate Concrete: Cost, Colours & Maintenance Guide
Exposed aggregate concrete is a decorative outdoor concrete finish where the surface paste is removed to reveal the stone inside the mix. It costs more than plain concrete, but gives better wet-weather grip, stronger street appeal and more colour choice for driveways, paths, patios and pool surrounds.
What is Exposed Aggregate Concrete?
Exposed aggregate concrete is not a separate structural category of concrete. It is a surface finish. The concrete is poured with stone aggregate in the mix, then the top layer of cement paste is removed so the stones become visible at the surface.
That exposed stone gives the concrete its texture, colour variation and grip. It is common on driveways, pool surrounds, front paths and outdoor entertaining areas because it looks more finished than plain grey concrete while still behaving like a durable outdoor slab.
Exposed Aggregate Concrete Cost in Australia
As a broad Australian guide, exposed aggregate concrete commonly costs about $90-160/m² installed for residential driveways and outdoor paving. The final price varies by region, supplier, access, slab thickness, reinforcement, site preparation, aggregate choice and sealing system.
| Cost driver | Why it matters | Typical effect |
|---|---|---|
| Aggregate selection | Standard local stone is cheaper than premium imported or decorative blends. | Can add $10-50/m² |
| Surface retarder and washback | The finish needs extra timing, labour and cleanup. | Raises labour cost |
| Sealer | Exposed aggregate should be sealed to protect the matrix and improve cleanability. | Initial and recurring cost |
| Access and site prep | Sloped blocks, poor truck access, excavation and base correction increase the job price. | Often bigger than finish cost |
For a local example with Sydney driveway pricing, see the Sydney exposed aggregate vs standard concrete comparison.
Colours, Stones and Finish Options
The finished look comes from the aggregate and the cement matrix around it. River pebbles create a warmer natural finish, basalt and granite read darker and more architectural, while quartz, marble chips and recycled glass are usually premium decorative options.
| Option | Appearance | Best fit |
|---|---|---|
| River pebble | Rounded stones, cream, tan, brown and grey tones | Driveways, paths, general residential work |
| Basalt or blue metal | Darker, angular, modern finish | Contemporary homes and commercial entries |
| Granite | Speckled premium stone | Feature paths, entries and pool surrounds |
| Quartz or light stone | Bright, reflective, lighter surface | Pool areas and high-visibility landscaping |
| Oxide-coloured matrix | Stone plus coloured concrete background | Custom driveway and landscape designs |
Where Exposed Aggregate Works Best
- Driveways: the most common use, especially where street appeal matters.
- Pool surrounds: strong wet-weather grip and a natural stone look.
- Front paths and entries: a durable way to make the approach to the home look more complete.
- Patios and alfresco areas: good for outdoor entertaining where plain concrete would look too utilitarian.
- Public paths and commercial entries: a hard-wearing textured surface for foot traffic.
Exposed Aggregate vs Plain Concrete
Plain concrete is usually cheaper and easier to patch. Exposed aggregate is usually better looking and more slip resistant, but it needs a skilled finish and more deliberate maintenance. Both can use the same concrete grade, thickness and reinforcement; the difference is the surface treatment.
How Exposed Aggregate is Installed
- Choose the concrete grade and aggregate blend. Select a concrete grade suitable for the use, then choose the stone colour, size and finish available from local suppliers.
- Prepare the base, forms and reinforcement. Compact the sub-base, set falls for drainage, install formwork and place reinforcement according to the project specification.
- Place and screed the concrete. Pour the concrete, screed it to level and complete the initial finishing while keeping the chosen aggregate evenly distributed.
- Apply surface retarder. Apply surface retarder to delay set at the top of the slab while the body of the concrete continues to harden.
- Wash back the surface. After the correct set time, wash away the softened cement paste to expose the stone without dislodging the aggregate.
- Cure and seal the surface. Allow the concrete to cure, then apply an exposed aggregate sealer to protect the surface and improve cleanability.
The washback timing is the hard part. If it is washed too early, stones can dislodge. If it is washed too late, the cement paste can set too hard and the exposure will be patchy.
Maintenance, Cleaning and Resealing
Exposed aggregate is low maintenance, not no maintenance. The surface should be kept clean, oil and rust stains should be treated early, and the sealer should be refreshed before the surface becomes porous or chalky.
| Timing | Task |
|---|---|
| Monthly or as needed | Hose or sweep grit, leaves and dirt from the surface. |
| After spills | Clean oil, tannin, paint and rust marks quickly before they soak in. |
| Every 12 months | Check for sealer wear, whitening, cracks and drainage issues. |
| Every 3-5 years | Reseal, depending on traffic, sun exposure, coastal conditions and product type. |
Common Problems to Watch For
Cracking
Usually caused by base movement, poor joint layout, rapid drying, excess water, inadequate thickness or structural loads. Exposed aggregate does not stop concrete behaving like concrete.
Efflorescence
White mineral residue can appear when moisture carries salts to the surface. Clean it before resealing so it is not trapped under the sealer.
Patch Matching
Repairs are hard to hide because aggregate blend, exposure depth, age and sealer condition all affect the final appearance.
Sealer Whitening
Milky or cloudy sealer can come from moisture trapped under the coating, incompatible products or resealing before the surface is dry.
Regional Differences in Australia
Exposed aggregate varies by region because stone is heavy and many suppliers use local quarry materials. That is why colour ranges in Sydney, Melbourne, Brisbane, Perth and regional markets can look different even when the finish type is the same.
Regional pages should carry local price bands, supplier availability, climate notes, driveway examples and suburb links. This national page should stay broad; local pages should answer buying and availability questions for each market.
Frequently Asked Questions
What is exposed aggregate concrete?
How much does exposed aggregate concrete cost in Australia?
Is exposed aggregate concrete different from normal concrete?
Where can exposed aggregate concrete be used?
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What is efflorescence on exposed aggregate?
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Can exposed aggregate be customised?
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