People have been building in concrete for thousands of years and indeed it is obvious that one of the most beautiful (if not the most beautiful) building in the world was shaped with the stuff before 126 AD 

These days everyone has heard of concrete cancer and when it is mentioned in relation to your strata plan it can cause serious angst within the body corporate. The situation is not calmed at all when people can readily google it... for instance this:

 

"Corrosion of steel reinforcement in concrete structures is well known to be "Concrete Cancer", which is a significant worldwide problem and causes multi-billion dollars losses to the infrastructure and building owners each year. The detection, diagnosing and appropriate treatment of this complicated problem requires very special expertise in this field."

Exacerbating the situation more are the people who are almost experts... every bump in a concrete soffit seems cause sufficient for them to raise the spectre of dire consequences, doom and gloom with the threats of widespread concrete coring, special levies, wildly inaccurate speculations speckled through the strata meeting minutes sending fear into the hearts of prospective purchasers and driving down property values un-necessarily, but offering nothing but the drama to deal with the problem.

Concrete Spalling at drip groove (horizontal). The vertical mark is not a structural issue. It's caused by concrete slurry bleeding though a joint in the formwork during wet concrete placement.

 

What's the best strategy?

If you think you have a problem get someone in early who knows what they are looking at. The best strategy is to engage someone experienced to orchestrate the rectification work and report to the Strata plan on the process. Someone dispassionate, calm and collected and experienced in construction contracts. Someone widely experienced in building and architectural construction finishes, and someone experienced in dealing with competing interests of the various experts, tradesmen, authorities, legislation, owners and their representatives.

 

How do you solve your spalling problem?

All projects and circumstances are unique so the best solution is tailor made by someone without a pre-determined strategy.

 

We recently inspected a strata property at Coogee in which all the visual signs indicated that concrete was spalling only at the drip groove (photo above). The likely culprit was that the underlying steel reinforcing was simply tied too close to the formwork during construction and therefore the steel was corroding due to water penetration. That's a builder's construction defect, not a design defect. Proper supervision by the builder could have avoided that issue entirely. With appropriate witness points, a well established contract with an experienced person representing the Principal could also have helped avoid it.

The spalling affected 24 balconies. In this instance we arranged for a couple of test core samples, that is two partial depth cores to get a feel for whether there was a more sinister underlying issue, in what visually appeared to be the worst affected balcony. The test cores showed bright reinforcing steel and the lab test results confirmed a normal chloride ion content range. On that basis, we recommended a lump sum contract for all preliminaries, plant, labour and materials except the spalling repairs which was performed on a schedule of rates basis. We closely monitored and measured the extent of spalling repairs during execution of the work and adjusted the contract sum accordingly. We had a very co-operative builder and that is an essential pre-requisite to a happy outcome.