CAWS repairs concrete cancer and spalling concrete across Perth, on apartment balconies, slab edges and soffits, car parks, columns and family homes. We break the damaged concrete out, treat the steel properly and fix the water or salt that caused it, so the repair lasts.
Signs of concrete cancer
Rust stains bleeding through concrete or render
Cracks running along a balcony edge, column or beam
Concrete that sounds hollow when tapped, or is lifting and flaking off
Exposed, rusty steel reinforcement
Pieces of concrete falling from soffits or slab edges
What causes it
Concrete protects the steel inside it. Over time, salt from the sea air and carbon dioxide break that protection down, the steel rusts and swells, and the concrete cracks and falls away. Perth’s coastal air and leaking balconies or roofs speed it up.
How concrete cancer happens
01Protected
High alkalinity keeps a protective layer on the steel.
02Salt and CO2 get in
Sea air and carbon dioxide work through the concrete cover.
03Steel rusts and swells
Rust takes up several times the space of the steel and cracks the concrete.
04Concrete spalls
The cover breaks away, letting in more water and speeding up the damage.
→What it looks like
A spalled slab edge with the rusted steel exposed.
Find the full extent. We sound out the area to find all the drummy concrete, not just what you can see, and look for where the water or salt is getting in.
Break out behind the steel. Damaged concrete is removed back past the corroded steel, so the repair bonds to sound material.
Clean and treat the steel. Rust is removed and the steel is primed. Where too much of a bar has been lost, it is replaced or supplemented to an engineer’s design.
Reinstate and protect. The area is rebuilt with a suitable repair mortar and finished with a protective coating.
Fix the cause. If a balcony, roof or planter is letting water in, we waterproof it too. Otherwise the damage comes back.
Hand over. We photograph the finished repair, so you have a record.
Slab soffit broken out to expose the reinforcement mesh during concrete cancer repairReinforcement treated and primed across a soffit before the concrete is reinstated
Where we repair it
Balconies and slab edges on apartments and homes
Soffits and ceilings, including work from scaffold or swing stages
Car parks, decks, ramps and columns
Columns, beams and facades on strata and commercial buildings
Driveways, carports and stairs around the home
Concrete repairs underway across a large slab soffit from mobile scaffoldScaffold towers on a strata apartment building for balcony remediation
Facade and parapet repairs on a shopfront from an elevated work platformFormwork and props in place to reinstate a concrete stair
Galvanic anodes
Most concrete cancer repairs don’t need them. Where an engineer or the project specification calls for them, we install zinc galvanic anodes with the repair to give the surrounding steel extra protection.
Common questions
Is concrete cancer dangerous?
Falling concrete is a real safety risk, so keep people clear of any area that is spalling. In advanced cases, lost steel can affect the strength of a slab or beam, and a structural engineer should assess it.
Can it just be patched or painted over?
No. A patch or paint over rusting steel hides the damage while it keeps getting worse, and can even speed up corrosion next to the patch.
