A cracked, flaking driveway and a slab with concrete cancer can look almost identical from where you’re standing. One needs a cosmetic overlay costing $30 to $120 per square metre. The other needs the steel inside it cut out and rebuilt before any finish goes near it. What decides which job you’re facing isn’t how bad the concrete looks but whether the reinforcement inside has started to corrode.
Why the two problems look the same
Both jobs present the same way: cracking, flaking, patches breaking off and rust-coloured marks. Standing over the slab, you can’t tell whether the surface is simply worn out or the concrete is failing from the inside.
Spalling is the clearest example. Concrete chipping and breaking away in chunks can be nothing more than a weak, poorly finished top layer giving up after twenty summers. It can also be the visible end of a process that started years ago inside the slab, where corroding steel has been pushing the concrete apart. The appearance is the same and the job is not.
What decides it is the steel within
Reinforced concrete works because the steel inside is sealed away from water and air. Get that right and the steel never corrodes. Let water reach it through cracks or porous concrete and it rusts, and rust takes up more room than the steel it formed from. As UNSW’s School of Materials Science and Engineering explains, that expansion forces the existing cracks wider, which lets in more water and corrodes more steel and the damage accelerates itself.
The part doing the structural work is the part being destroyed. Cosmetic damage stays cosmetic, but corrosion eats into the load-bearing capacity of the slab while the surface still looks merely tired.
A slab in the early stages of concrete cancer is a smaller, cheaper repair than the same slab in two years. Waiting to see whether it gets worse is the most expensive option available.
What each service does on site
Concrete resurfacing bonds a thin polymer-modified cement layer, between 1.6mm and 13mm, over your existing slab. It covers crazing, pitting, staining and surface spalling, and leaves a uniform finish for a fraction of the cost of a re-pour. It assumes the slab underneath is sound, because the overlay adds no strength.
Concrete restoration repairs the structure. Deteriorated concrete is cut back to sound material, the exposed reinforcement is treated, and the section is rebuilt. Structural cracks are injected with epoxy or polyurethane resin to bond the concrete back together, and where more capacity is needed, carbon fibre wrapping, steel plates or additional rebar go in. Joints are rebuilt and resealed. Once the structural work is sound, the surface is cleaned, stains and contaminants are removed, and the concrete is ground or refinished so the repaired area sits consistently with the rest of the slab. Protective coatings go on last.
| Concrete resurfacing | Concrete restoration | |
|---|---|---|
| The problem it fixes | Surface wear on a structurally sound slab | Structural damage and corroding reinforcement |
| What happens on site | A 1.6–13mm overlay is bonded to the existing concrete | Failed concrete is cut out, the steel is treated, the section is rebuilt and refinished |
| Adds structural strength | No | Yes |
| Usual triggers | Crazing, pitting, flaking, bore stains, a worn finish | Concrete cancer, deep spalling, structural cracking, moisture at joints, staining too deep to clean off |
| How it’s priced | Per square metre, $30 to $120 in Perth | Per job, after inspection |
| What it costs to get wrong | The overlay lifts within months and you pay for the job twice | Money spent on strength a sound slab didn’t need |
Resurfacing over concrete cancer is the more expensive of those two mistakes. The overlay bonds to concrete that’s already delaminating, so the new surface lifts within months, and the restoration job then includes removing the overlay you just bought.
Restoration often finishes with a resurfaced or coated surface, so the two services overlap at the end of a job.
Four signs the steel is involved
- Rust-coloured staining bleeding out of the concrete: brown or orange streaks with no obvious external source usually mean the reinforcement is corroding and the products of that corrosion are working their way out.
- Cracking that follows a straight line or a grid: cracks running parallel to an edge, or in a regular pattern, are often tracing the reinforcement bars underneath as they expand.
- Spalling with steel visible in it: once you can see bar or mesh in the broken-out area, the protective cover has gone and the corrosion has direct access to air and moisture.
- A dull, hollow sound when you tap the surface: tap along the slab with a hammer or a length of steel. Where the concrete rings solid it’s still bonded. A drummy, hollow note means the layer above the steel has already separated, even if nothing has broken off yet. It’s usually the earliest sign you can find without cutting into anything.
If none of that is present, the damage is surface-level: fine crazing, shallow pitting, bore stains or a slab that’s simply old.
Perth concrete gets there sooner
Chloride is one of the main drivers of reinforcement corrosion, and it doesn’t only reach concrete through direct contact with seawater. Salt-laden air settles on the surface, works through the pores and breaks down the film protecting the steel. That’s why Australian concrete standards treat coastal structures as a more severe exposure than inland ones. Corrosion is a big enough problem in WA that Curtin University’s Corrosion Centre runs research dedicated to marine structures around the state.
Two slabs of the same age and the same mix, one in Scarborough and one thirty kilometres inland, aren’t carrying the same risk. Add Perth’s wet winters and dry summers moving the ground beneath them, and older coastal concrete is worth checking properly rather than assuming a resurface will do.
The work that sits between the two
Treating this as a choice between a coating and a rebuild leaves out the work in the middle. Plenty of slabs are structurally sound but well past the point a clean and seal will fix, and an overlay isn’t the only way to bring them back. On our concrete restoration jobs this is the surface restoration and refinishing stage, and it doesn’t need any structural repair to go with it.
Where a sound slab has good-quality aggregate, we can grind it to a honed or exposed aggregate finish instead of laying an overlay over the top. A honed finish grinds the surface smooth for a polished, even look. An exposed aggregate finish cuts back the top layer to reveal the decorative stone beneath. Both are worked into the slab you already have, so there’s no top-coating required and nothing that can later peel or delaminate.
Deep staining is the other case. Where oil, rust, efflorescence, paint or traffic staining is past what high pressure cleaning can shift, we grind it back and refinish the concrete. The stain comes out with the top layer rather than being coated over. On a slab that’s otherwise sound, that can be the whole job.
Who should be looking at it
We resurface, we restore, and we grind existing slabs back to a honed or exposed aggregate finish, so our inspection can price every answer your concrete might need. We carry the skills and the equipment for all of it.
That inspection is thorough enough to capture the full scope. Where the damage is structural or the extent isn’t clear, we engage a structural engineer to assess the concrete, so the scope rests on an engineering assessment rather than a guess at what’s underneath.
Restoration jobs usually need several kinds of work: diagnosis, structural repair, surface preparation, refinishing and coating. We hold the whole scope and manage the project from assessment through to the final coating, which means one point of contact and no gaps between stages where problems get missed.
We also tailor the scope to your budget. Where a full restoration isn’t viable right now, we’ll tell you what has to be done to keep the structure safe and what can wait.
Get it looked at before you get it quoted
The honest answer to “resurface or restore?” is that you can’t reliably tell from photos, and neither can we most of the time. It takes someone on site checking for delamination, reading the cracking pattern and working out whether the steel is involved.
FCT Surface Cleaning has been WA family-owned and operated since 1994. We’re Cm3 prequalified, fully insured and a government-approved contractor, and we do both jobs, so we’ll tell you which one your concrete needs.
Call (08) 9204 3333 or request a free, no-obligation quote, and we’ll come and take a proper look. You can also see our completed projects across residential, commercial and industrial sites in Perth.
What's the difference between concrete resurfacing and concrete restoration?
Resurfacing applies a thin cosmetic overlay to a slab that’s structurally sound but worn or stained. Restoration repairs concrete that’s damaged beneath the surface, addressing steel corrosion, spalling and structural cracking before any finish is applied. Resurfacing improves how concrete looks, and restoration fixes what it’s doing.
Can concrete cancer be fixed by resurfacing?
No. An overlay adds no strength and doesn’t stop corrosion, so the steel keeps expanding and the new surface fails with the concrete beneath it. Concrete cancer needs the deteriorated concrete cut out, the reinforcement treated, and the section rebuilt before any cosmetic finish goes on.
How can I tell if my concrete has structural damage or just surface wear?
Look for rust staining, cracking that runs in straight lines or a grid, exposed steel in broken-out areas, and a hollow sound when you tap the slab. Any of those point to structural damage. Fine crazing, shallow pitting and stubborn staining on an otherwise stable slab are surface problems.
Is concrete restoration more expensive than resurfacing?
Usually, yes. Resurfacing is priced per square metre and sits between $30 and $120 in Perth, depending on the finish and the preparation needed. Restoration is priced per job, because the cost depends on how far the damage has gone and how much reinforcement needs treating. Resurfacing a slab that needed restoring ends up costing more than doing it right the first time.
Can you grind my existing concrete instead of putting an overlay on it?
Yes, where the slab is structurally sound and the aggregate is good quality. We can grind it to a honed finish for a smooth, polished look, or to an exposed aggregate finish that reveals the decorative stone beneath. The finish is worked into the slab itself, so there’s no top-coating required and nothing to peel or delaminate later.
Can you remove deep staining without doing any structural repair?
Yes. Oil, rust, efflorescence, paint and traffic staining are removed as part of the surface restoration stage of a restoration job, and on a sound slab that work can be done on its own. Where the staining has gone too deep to lift, we grind or refinish the concrete instead.
