Concrete cancer is a common term used when reinforced concrete deteriorates and the steel reinforcement inside the concrete begins to corrode. Rust occupies more volume than the original steel, which can create internal pressure. The surrounding concrete may then crack, delaminate or break away.
Why it happens
Moisture, chlorides, carbonation, inadequate concrete cover, cracking and exposure conditions can all contribute. The cause needs to be assessed rather than assumed from appearance alone.
What it looks like
Rust staining, cracking along reinforcement lines, spalling, exposed steel and drummy concrete are common warning signs.
What repair usually involves
A repair may require removal of unsound concrete, treatment of affected reinforcement, reinstatement with compatible repair materials and protective systems. Structural or widespread deterioration can require engineering input.
What to do next
Take clear photos of the wider area and close up damage, note the property location and where the concrete is situated, then arrange an on site assessment so the repair scope can be priced accurately.