Concrete spalling & repairs
Concrete cancer, spalling and cracks repaired on balconies, edges and facades.
View Guide · Remedial
Concrete cancer: signs, causes and repair
“Concrete cancer” is the everyday name for rusting steel inside concrete. It’s common in Sydney’s coastal air, and much cheaper to fix early.
- 15+ yearsin height & building work
- IRATAcertified rope access
- Licensedpainter & decorator · 471024C
- Fully insuredpublic liability & workers comp
What’s actually happening
Steel reinforcement is protected by the concrete around it. When moisture, salt or carbonation reach the steel, it rusts. Rust takes up far more space than steel, so it pushes the concrete apart from the inside, causing cracks and eventually chunks breaking away, spalling.
Warning signs
- Rust stains running from cracks
- Cracks along slab edges, balconies, columns and beams
- Bulging or drummy concrete that sounds hollow when tapped
- Pieces of concrete falling or exposed rusty steel
- Small rust spots on soffits, often “bar chairs” close to the surface
How it’s repaired
Many repairs on balconies and slab edges can be done by rope access, avoiding scaffold. Concrete spalling repairs
- Identify and mark affected areas.
- Break out damaged concrete to expose the steel.
- Clean and treat the steel, or replace it to an engineer’s specification.
- Reinstate with suitable repair mortar and protective coatings.
- Make good the finish.
Is concrete cancer covered by insurance?
It’s usually treated as maintenance or a defect rather than an insured event, but check your policy and speak with your strata manager.
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