Start with the right diagnosis
The cause of the damage decides the fix. A quick look at the symptoms usually tells the story.
Fine surface crazing. A web of hairline cracks across the surface, often from rapid drying when the concrete was poured. Usually cosmetic.
Shrinkage cracks. Straight or slightly wandering cracks, often between joints that were spaced too far apart. Usually stable once the concrete has finished shrinking.
Settlement cracks. Cracks with one side lower than the other, or panels that have sunk. Caused by a poor or washed-out base. A sign the problem is underneath.
Heave and root damage. Panels pushed up, often near trees. The cause is still active.
Scaling and spalling. The surface flaking off in patches, sometimes revealing rusty steel. Near the bay, salt can play a part, particularly where concrete was unsealed or the steel had little cover.
Staining and wear. Oil, rust, leaf tannins, efflorescence (white salty deposits) and worn-through finishes. Cosmetic, though some stains are stubborn.
When resurfacing works
A resurfacing overlay is a thin layer of polymer-modified cement product applied over existing concrete, often sprayed or trowelled, then patterned or coloured and sealed. It can give an old driveway a new look without removing it. It works when:
- the existing slab is level and solid, with no rocking or sunken panels
- cracks are stable and can be repaired first
- the surface is clean and sound enough for the overlay to bond
- you are happy with the current levels, since the overlay adds a little height
When resurfacing will not work
Overlays fail when they are asked to fix structural problems. Avoid resurfacing when:
- panels have sunk, lifted or tilted
- cracks are wide, active or have displacement
- tree roots are still pushing up the slab
- the existing surface is flaking, crumbling or contaminated with oil that cannot be removed
- drainage is wrong and water pools on the surface
In these cases, an overlay will crack or peel, often within a short time. Replacing the failed panels, or the full driveway, is money better spent. See driveway removal and replacement.
Repair options
Crack repair
Stable cracks can be cleaned out and sealed with either a flexible filler, where some movement will continue, or a rigid repair mortar where it will not. Repairs will usually be visible; the goal is to stop water getting in and edges breaking down.
Panel replacement
Where one or two panels have failed, they can be saw-cut at the joints and replaced, with the base corrected underneath. The new panel will look different from the old concrete at first, especially with colour or aggregate.
Patching and edge repair
Broken edges, spalled patches and chipped steps can be cut back to sound concrete and patched with repair mortars. Any exposed steel is cleaned and treated first.
Joint repair
Old timber or failed sealant in joints can be removed and replaced with a flexible joint sealant to keep water and weeds out.
Cleaning and sealing
Sometimes the best repair is a thorough clean and a quality sealer. Pressure washing, stain treatment and sealing can transform faded exposed aggregate. See concrete sealing.
Salt, scaling and spalling near the bay
Homes close to the water in Brighton, Sandringham, Black Rock and Elwood see more salt-related surface damage. Salt carried in sea air settles on concrete and is drawn in by rain. Over many wet-dry cycles, salt crystals can contribute to surface scaling, and where salt and moisture reach reinforcement with little cover, the steel can rust and expand, cracking the concrete above it. Repairs involve cutting back to sound concrete, treating the steel, patching with suitable repair materials and sealing to slow further damage. Where spalling is widespread, replacement may be more sensible. Our coastal concrete care guide explains prevention.
Can you pebblecrete or aggregate over existing concrete?
This question comes up often. A true exposed aggregate finish needs depth to hold the stones and generally cannot be applied as a thin layer over old concrete. Some decorative overlays imitate the look on sound slabs. If you want genuine exposed aggregate, replacement is usually the way. See exposed aggregate.
Trip hazards and safety
Lifted edges on paths and driveways are more than an eyesore. A raised lip of a centimetre or two is enough to catch a toe, a pram wheel or a walking frame, and the public footpath outside your home is the council's responsibility while the private path inside the gate is yours. Where a panel has lifted, options include grinding down a small lip as a temporary fix, cutting out and replacing the panel, or dealing with the root or base problem that caused it. If a crossover or council footpath outside the property is damaged, report it to the council or check whether it is your responsibility under their rules before arranging repairs.
How a repair or resurfacing job runs
Assessment
A site look identifies the cause and the realistic options.
Written quote
Repair, resurface or replace, with a clear explanation of why.
Preparation
Cleaning, grinding and crack or patch repairs before any overlay.
Application
Repair materials or overlay applied and finished.
Sealing
Protection against water, salt and stains.
Care advice
How long to stay off the surface and how to maintain it.
What affects a repair quote
- what kind of damage it is and how widespread
- area to be repaired or resurfaced
- surface preparation needed, including oil removal and grinding
- crack, joint and patch repairs
- overlay system, colour and pattern
- sealing
- access and the need to stage work around driveway use
No prices appear on this site. A free assessment gives you a written quote.
Repairs across Bayside
Salt-related repairs are more common near the foreshore in Sandringham and Black Rock. Settlement and root damage are typical of older driveways in Moorabbin and Highett. For a full rebuild, see driveway replacement.
Concrete repair FAQs
Resurface if the slab is solid and level with mainly cosmetic problems. Replace if panels have sunk, lifted or cracked badly. An honest assessment should tell you which.
Rarely. Repairs stop water getting in and edges deteriorating, but they usually remain visible, especially on coloured or aggregate surfaces.
That comes down to how sound the slab underneath is, the product, traffic and maintenance. On sound concrete with good preparation and regular re-sealing it can perform for years; on failing concrete it may not last at all.
That is usually efflorescence: salts carried to the surface by moisture. It can be cleaned off, and improving drainage and sealing helps prevent it coming back.
Surface flaking (scaling) can come from finishing problems, weak surfaces, salt exposure or water damage. The cause affects whether patching, resurfacing or replacement is best.
Often, yes. The panel is cut out at the joints, the base is corrected and a new panel is poured.
Related Services
Get a repair assessment
Send photos of the damage, close up and from a distance. We will arrange a free site look and an honest recommendation.