What you need to know
Four tell-tale signs of concrete cancer:
- Cracking, splitting or crumbling concrete.
- Rust stains that seem to come out from the concrete.
- The paint appears to be dropping down or bubbling from the soffits.
- Raised section of tiling or walkway coatings.
Concrete cancer or concrete spalling is the effect of steel reinforcements within a concrete slab rusting, which in turn causes the steel to expand up to 5 times its normal size and effectively destroys the concrete from the inside out, causing it to split and breakaway.
What are key signs to look out for?
It’s not always obvious what underlying problems are in a concrete structure, however cracking, honeycombing and spalling are relatively easy to locate. The real concern is the root of the problem and without proper technical support can be easily overlooked.
Things to look for are:
- Reddish/brown stains that are adjacent to cracked concrete or running down any part of a building.
- Concrete lifting/exploding out.
- Other cracks with signs of moisture coming through, they can sometimes look like white crystals or fluorescence.
The effects of concrete cancer according to Griffith University Architecture specialist
According to Griffith University Head of Architecture, Professor Gordon Holden, the effects of concrete cancer are particularly prevalent in older buildings due to inadequate building techniques often employed in the 1970s and 80s, resulting in an average lifespan of about 40 years.
What makes the concrete cancer epidemic even more alarming is that it as an internal issue, it is not always visible to the untrained eye. This is why it is imperative that building owners incorporate concrete cancer checks carried out by professionals into their annual maintenance reviews, in order to catch it early and avoid costly repairs, complete demolition, and hazardous living conditions caused by cracking and crumbling concrete.
- As the Gold Coast has one of the highest salt-air contents in the world, it’s this high salt content that accelerates the corrosion of the steel reinforcement.
- Insufficient or deteriorated paint coatings. A good paint/waterproofing coating will slow the cancer process greatly.
- Fractures (cracking) to the concrete allowing water and salt to penetrate the concrete and react with the steel.
- The original placement of reinforcing/bar chairs being too close to the surface (usually less than 50mm) allowing water to seep through concrete and react with the steel.
- Incompatible metals being used in close proximity to each other, thus causing a corrosion reaction.
Has concrete cancer a cure?
Unfortunately, there is no permanent cure, there is only preventative maintenance.
Using a High-quality waterproofing decretive coating will keep water seepage to a minimum, as they are more resistant to tears and punctures, they have longer lifespans and are more weather resistant. By preventing water from infecting your concrete, we can greatly slow the effects of concrete cancer in its tracks. If you have no waterproofing coverage or inadequate waterproofing coatings, your structure will be more susceptible to concrete cancer. Any area that moisture is getting in needs to be fixed before it has a chance to infect the concrete, including any cracks blister bubbles etc.