Causes of Concrete Spalling (cancer)
Concrete spalling occurs when salts are allowed to penetrate concrete and affect the structural steel which is embedded within the concrete. This usually occurs in or near coastal areas. The Building Code of Australia classifies areas within 1 Km of the ocean as severe marine environment and areas between 1 and 5 Km to be in a marine environment. Similarly, areas within 5 Km of still saltwater locations such as a lakes and harbours are classified as a marine environment. Those locations contain a degree of salt laden air which can penetrate the surface of concrete.
When the concrete external slabs such as balconies have insufficient “cover” of concrete over the structural steel within the concrete slab, then the salt laden air can penetrate that surface area of concrete and affect the structural steel. If the repairs are not undertaken in reasonable time, then the deterioration will continue. In extreme cases, a balcony or impacted area can collapse.
The repairs required will depend on the extent of damage to the structural steel. There are other issues to be considered such as any additives within the concrete which can accelerate the degree of deterioration. Where the damage is no major, it may be possible to remove the damaged concrete and grind and remove the rust from the steel, provide a protective coating and repair the surface. The degree of works required will be dependent on a professional Expert to inspect and determine the extent of repairs required.