Diagnose and Fix Concrete Cancer in Buildings with Projex Group

While the term hints at how severe this type of damage is, it is possible to fix concrete cancer in some cases. Before you get started, you'll need to understand what concrete cancer is, what you can do about it, and the importance of getting expert help.

The concrete used in buildings is reinforced with steel and iron bars or mesh. When exposed to air and water (such as through leaks from a higher level), a weak carbonic acid starts to form and the bars begin to corrode. Concrete is a porous material and can easily absorb the elements around it - including this corroding acid. Once corrosion starts, the steel expands, causing the surrounding concrete to crack, known as spalling. Spalling can set off a vicious cycle by further exposing the steel to the elements and accelerating the level of corrosion. The impact on the building leads to a tragic compromise of structural integrity. Flat concrete roofs are an example of a building structure particularly vulnerable to leaks and water-driven concrete cancer if they're not adequately waterproofed.

Six common causes of concrete cancer include:

1. Poor waterproofing
2. Salt-water chlorides for buildings near the sea
3. Building defects
4. Weather
5. Poor quality concrete and insufficient concrete cover
6. Movement of the earth under the build leading to cracks

How to fix concrete cancer

If you suspect your building has been affected by concrete cancer, make sure you get it checked by a professional so you know what type of repair work has to be done. The earlier you catch it and have it fixed, the more likely you can avoid paying more for repairs than you have to.

Spotting the signs yourself

A structural engineer can diagnose concrete cancer accurately, but you might be able to work out if your building has been afflicted by the problem by looking out for a few tell-tale signs. Cracking or crumbling concrete, and rust stains emerging from the concrete/cement render are common signs. Others include bubbling concrete render and roof leaks, or leaks in internal walls. Concrete expanding outwards could also be a sign of concrete cancer.

Diagnostic analysis of concrete cancer

Every concrete cancer repair job starts with a detailed diagnosis of the problem. Have a qualified engineer conduct a diagnostic analysis. Working with a structural engineer is important since a repair contractor or repair materials supplier might not be adequately qualified to complete the job. The engineer can identify the cause of the problem and outline what needs to be repaired.

Correct the problem

Depending on the cause of concrete cancer, the engineer might recommend different solutions.

1. Polymer modified repair system solution

   For situations where concrete carbonation and low concrete cover are the issues, the engineer might recommend using a polymer modified repair system. This option removes the concrete around the reinforcing bars and cleans the steel, before applying both the steel primer and a polymer modified material. They might also apply an anti-carbonation protective coating to the whole concrete surface. Sometimes the experts might recommend using additional reinforcing steel anodes before new concrete is applied, or the steel might be replaced in severe cases.

2. Electrochemical treatment option

   If it's a case of chloride contamination in a building near the ocean, you might need to have specialist repair work done to treat concrete cancer. This can include electrochemical treatment, such as cathodic protection.

3. Simple replacement method

   If it's a case with less severe damage, you might be able to remove the damaged concrete, clean and replace the rusted, exposed steel, and fill in the cracks.

Don't miss the last step

Once the underlying steel and concrete have been repaired, you'll need to allow it to cure properly; specialist coatings might be used at this stage. Then you can have finishings, paints, and protective coatings reapplied, be sure to include the application of waterproofing.

Waterproofing as a preventative to concrete cancer

Once you've fixed concrete cancer, take preventative steps so it doesn't happen again. Waterproofing concrete is essential to prevent water from corroding the steel beams. Consider high-quality waterproofing options such as Wolfin or Cosmofin waterproofing membranes to seal the new concrete horizontal surfaces. This minimises the risk of future water damage and prevents harsh chemicals contaminating the concrete from entering through pores. This is an important preventative because poor waterproofing, or worse, no waterproofing, could undo all the repair work on your building.

When it comes to concrete cancer, there's no one-size-fits-all solution. The best repair option depends on your building materials and the extent of the damage. Regardless of whether the damage is severe or moderate, waterproofing and comprehensive sealing after the repair are important to minimise the risk of concrete cancer reoccurring.

Projex has been a leading supplier of outstanding engineering and waterproofing products for over 25 years. We're committed to providing the highest quality materials to solve a range of waterproofing and engineering issues.

Talk to one of our qualified sales staff or visit www.projex.com.au to find out more about our waterproofing products.