Exposed aggregate concrete is valued for its durability, natural appearance and resistance to wear. But like any exterior surface, it benefits from regular upkeep. A consistent maintenance routine will preserve its colour, prevent staining and extend the life of the sealer that protects the surface from moisture and UV damage. The good news is that maintaining exposed aggregate is straightforward and does not require specialist tools or chemicals. Here is a practical, season-by-season approach that any homeowner or property manager can follow.
Why Maintenance Matters
When exposed aggregate is first laid, the contractor applies a penetrating or film-forming sealer that locks in the colour and creates a barrier against water absorption, oil stains and algae growth. Over time, foot traffic, vehicle movement, weather and UV exposure gradually degrade this protective layer. Without resealing, the surface becomes more porous, allowing dirt, mould and stains to penetrate deeper into the aggregate.
Regular cleaning slows this degradation, and periodic resealing restores the protection to near-original levels. The cost of maintenance is minimal compared to the expense of replacing or resurfacing a neglected driveway or patio.
Autumn: Clear and Clean
As trees shed their leaves, organic debris can accumulate on concrete surfaces. Wet leaves left sitting on exposed aggregate for extended periods release tannins that stain the surface, particularly on lighter-coloured blends. Sweep or blow leaves regularly, paying special attention to areas near garden beds and under trees.
Autumn is also a good time for a thorough clean. Use a garden hose with a fan nozzle or a pressure washer set to a moderate pressure — between 1500 and 2500 PSI. Higher pressures can dislodge aggregate particles or damage the sealer, so keep the nozzle at least 300mm from the surface and use a sweeping motion rather than holding it in one spot.
For stubborn marks, a mild concrete cleaner diluted according to the manufacturer's instructions will lift most stains without harming the sealer. Avoid bleach-based cleaners on coloured aggregate as they can cause discolouration.
Winter: Inspect and Repair
South Australian winters bring cooler temperatures and intermittent rain. While exposed aggregate handles moisture well, any cracks or chips in the surface can allow water to penetrate the substrate. During winter, walk the surface and look for hairline cracks, loose aggregate stones or areas where the sealer has visibly worn away.
Small cracks can be filled with a flexible concrete repair compound available at most hardware stores. Loose stones can sometimes be re-adhered with an exterior construction adhesive. For larger areas of damage, contact a professional concrete contractor who can assess whether a localised repair or a full reseal is needed.
Spring: Deep Clean and Assess
Spring is the ideal time to prepare your exposed aggregate for the warmer months ahead. Start with a thorough pressure wash to remove any dirt, algae or mould that accumulated over winter. If green algae has taken hold in shaded areas, an algae-specific concrete cleaner will clear it effectively.
After cleaning, assess the condition of the sealer. Sprinkle water on the surface — if it beads up, the sealer is still performing well. If it absorbs into the concrete and darkens the surface, it is time to reseal. Most exposed aggregate surfaces need resealing every three to five years, depending on traffic and sun exposure. A quality solvent-based or water-based sealer applied in two thin coats will restore colour vibrancy and protection.
Summer: Protect and Maintain
The harsh Australian summer subjects outdoor concrete to intense UV radiation, high temperatures and occasional storms. The sealer is your primary line of defence during this period. If you resealed in spring, your surface should be well protected.
During summer, focus on prompt spill cleanup. Oil drips from vehicles, barbecue grease, red wine and fertiliser can all stain exposed aggregate if left unattended. Blot up spills as soon as practical and rinse the area with clean water. For oil stains, a degreaser formulated for concrete will draw the oil out of the pores without damaging the sealer.
Avoid dragging heavy or sharp objects across the surface, as this can scratch the sealer and dislodge aggregate. Use furniture pads under outdoor settings and avoid turning vehicle steering wheels while stationary on the surface, as this creates localised scuff marks.
Long-Term Care
With consistent seasonal maintenance, an exposed aggregate surface from Clustries will look outstanding for twenty years or more. The aggregate itself does not deteriorate — it is natural stone that has already endured millions of years of geological forces. Your role is simply to protect the binding cement and sealer that holds the surface together.
If you are planning a new project and want advice on which aggregate blend and sealer combination will best suit your conditions, contact our team or visit the Thebarton showroom. We are always happy to share what we know.