A lot of concrete gets cleaned without the prep that actually makes it last. Skip a step, use the wrong cleaning method, or reach for whatever sealer is on the shelf, and you end up with a faded finish, flaking, or damage that shows up sooner than it should. Driveways, pool areas, and paths take in dirt, water, and oil constantly, and once stains sit in the slab, restoring it costs a lot more than doing it properly the first time.
Why cleaning and sealing matters
Concrete is porous, so left untreated it lets moisture, grime, and oil settle deep into the slab, weakening the surface over time. Regular cleaning clears the build-up, and sealing puts a barrier over the top that limits new staining and slows erosion. Melbourne's temperature swings and rainfall push concrete through constant expansion and contraction, and a sealed slab handles that far better than a bare one, staying more stable and holding its colour instead of fading in the sun.
Prepare the surface before you clean
Start with a clear, dry surface, sweeping or blowing away loose debris first. Cleaning a damp or dirty slab just spreads the grime rather than lifting it. Check for cracks or pits and patch them before cleaning, since gaps left open let water in and cause deeper damage later. If there's old sealant peeling or flaking, strip it back before applying anything new, otherwise the fresh coat won't bond properly. Pick a dry stretch of weather, ideally with no rain forecast for at least 24 hours.
Choosing a cleaning method
The right method depends on what you're removing. For general dirt, a broom and hose usually does the job. For oil or mildew, you need something stronger.
- Pressure washing works well for driveways, patios, and paths. Keep it under 3000 psi to avoid damaging the surface, angle the spray at 45 degrees, and test a corner first.
- Hand scrubbing with a stiff brush, warm water, and a concrete-safe cleaner suits smaller spots or indoor areas.
- Match the cleaner to the stain: a degreaser for oil, a mould and algae remover for shaded areas, and a pH-neutral cleaner for sealed or decorative concrete.
Acid-based cleaners can shift stubborn stains but need real care, always rinse thoroughly and use gloves, eye protection, and good ventilation.
Selecting the right sealer
Not every sealer suits every surface. Penetrating sealers soak into the slab and suit outdoor areas well, forming a barrier without changing the look and needing less frequent reapplication. Acrylic sealers give a gloss or satin finish and suit stamped or coloured concrete, though they typically need reapplying more often. Polyurethane sealers build a tougher surface layer for driveways and garages, resisting scuffing and tyre marks. Epoxy suits indoor workshops or floors exposed to chemicals, forming a thick coat that stops spills soaking in, though it needs a dust-free environment to apply properly.
Applying it properly
Timing makes the difference between a sealer that lasts and one that lifts or bubbles. The surface needs to be completely dry, even a little trapped moisture causes poor bonding. Use a sprayer for large or textured areas, a roller for smooth slabs, and a brush for edges and corners. Apply thin coats and let each one dry fully before the next. Keep the area off-limits until it's cured, at least 24 hours for foot traffic and longer for vehicles.
Getting it assessed properly
Every slab wears differently depending on its age, use, and exposure. We assess the surface on-site and match the cleaning method and sealer to what's actually needed, rather than a one-size approach. If your concrete is starting to stain, wear thin, or lose its finish, our resurfacing page has more detail, or get in touch for a site check.