The cost of ignoring it
Left alone, concrete cancer compounds. A $15k slab-edge repair deferred two years routinely becomes a $60k+ structural scope with crack propagation, falling-debris risk and engineering intervention.
The defect, plainly
“Concrete cancer” is reinforcement corrosion: the steel inside the concrete rusts, expands, and breaks the concrete apart from within. You see it as spalling (chunks breaking away), rust staining, drummy render, or cracked slab edges on balconies and facades. It is progressive — the mechanism feeds itself as cracking admits more moisture, oxygen and chlorides.
Diagnostic approach
We do not quote from a photo. A concrete repair scoped without investigation is priced to be wrong — either padded against the unknown or destined for variations.
Our investigation typically includes:
- Visual and hammer survey of all accessible elements, defects tagged and photographed against a numbered schedule
- Cover meter survey to map reinforcement depth and identify low-cover zones
- Carbonation depth testing (phenolphthalein) on fresh break-outs
- Chloride sampling where marine exposure or admixture history warrants it
- Half-cell potential mapping on critical elements to find active corrosion that has not yet cracked the surface
The output is a written condition report: defect schedule, cause analysis, repair options with honest trade-offs, and a prioritised scope.
Repair methodology
Repairs follow the principles of AS 1379 / Concrete Institute guidance and the specified system’s technical manual:
- Break out to sound concrete, minimum 20mm behind corroded bars, saw-cut edges — no feather-edging
- Treat reinforcement: abrasive clean to bare steel, assess section loss (engineer referral where loss exceeds tolerance), prime with active zinc-rich or cementitious primer
- Reinstate with polymer-modified repair mortar matched to substrate strength, cured properly — not rushed
- Protect: anti-carbonation coating or penetrating inhibitor across the element, not just the patch, so the ring-anode effect doesn’t relocate the corrosion to the patch perimeter
Every stage is a hold point with photographic records. You receive the evidence trail, not just an invoice.
Where this shows up
Balcony slab edges and soffits, facade panels and window hoods, carpark slabs and columns, planter boxes, lift overruns and plant decks — anywhere reinforced concrete meets weather, and especially anywhere built between the 1960s and 1990s with the cover tolerances of the era.