Concrete Cancer Repair FAQ — Central Coast

There is no fixed price. The main drivers are how far corrosion has spread through the reinforcing steel, how much concrete has to be cut back, what access is needed (a ground-level carport beam is a very different job from a balcony three floors up), and what reinforcement and coating the exposure calls for. A small early patch is usually a minor job; common-property remediation across a unit block is a structural project. On an older beachfront structure, an asbestos check or engineering advice may come before the concrete work and add to the cost.

The basic method is the same: cut out the damaged concrete, treat or replace the rusted steel, rebuild and seal. What changes is the specification. Sea spray carries chlorides into concrete, and chlorides speed up corrosion of the reinforcing steel. For a local reference, the Terrigal Rock Pool works that Central Coast Council outlined in 2017 specified new concrete walls with stainless steel reinforcement. For a beachfront balcony, slab or retaining wall, ask the contractor what steel treatment, repair mortar and coating they propose, and why. On a frontage like Wamberal, where council reported 43 residences impacted by storm erosion in July 2020, the ground may need an engineer's view first.

First, get the extent scoped by a concrete repair contractor. A building and pest report flags the problem but usually does not scope the repair. Second, on an older structure, ask about asbestos before anything is broken out, cut or ground. In its July 2020 FAQ on the Wamberal Beach erosion, Central Coast Council said the building waste exposed on the beach came from private property, and that it had removed asbestos from Wamberal and Terrigal since the community first reported it there in 2018. Ask for the scope in writing. It is useful for price negotiations, strata planning or an insurance claim.

Sometimes, but not automatically. Cover usually turns on the cause: sudden accidental damage is more likely to be covered than gradual deterioration from age and weather, which many policies exclude. On a strata-titled block, whether the damaged concrete is common property or part of a lot depends on the strata plan, and that generally decides whether the owners corporation or the lot owner is responsible. Check the policy with the owners corporation or the insurer, and ask for a written report on the damage and its likely cause to support any claim.

It is not recommended. Filler or render over active concrete cancer traps moisture and salt against the rusting steel, so the corrosion keeps going underneath where you cannot see it. A lasting repair cuts back the damaged concrete until clean steel is exposed, treats or replaces the corroded bars, rebuilds with a structural repair mortar and then seals the surface. Skipping those steps usually just delays a bigger repair. On an older structure, do not cut or grind anything until it has been checked for asbestos.

A single balcony or small patch is typically a few days of work, because repair mortar and coatings need curing time between stages. Larger strata jobs across several balconies or a whole facade can run for weeks, staged so parts of the building stay in use. Rain matters for exterior work, since membranes and coatings need a dry surface. Bureau of Meteorology averages for the Norah Head weather station (1995 onwards) show June as the wettest month, at 143.8 mm, and September as the driest, at 62.1 mm. Ask the contractor how they plan the job around wet weather.