Concrete cancer is a serious issue that can cause extensive and costly property damage. It occurs when steel reinforcement inside a concrete slab begins to rust, expanding and displacing the surrounding concrete, making it brittle and prone to cracking. Given the process cycle of exposure, corrosion and further degradation, the condition will only worsen if left untreated. It is essential to take preventive measures to avoid concrete cancer, such as waterproofing concrete with high-quality membranes like Wolfin or Cosmofin.
Six common causes of concrete cancer include poor waterproofing, salt water chlorides, construction defects, weather, poor quality concrete and insufficient coverage, and soil movement under construction. Magnesite floor covering is also a major culprit, as it leaches aggressive chloride ions into the concrete. Concrete cancer is caused by the reduction of the highly alkaline nature of freshly poured concrete due to water ingress through two main processes. Poor waterproofing or lack thereof can lead to corrosion of steel beams, while chloride pollution in buildings near the sea can cause significant damage.
Repairing heavily damaged concrete can be expensive and may not be profitable compared to replacing it. If the damage is less severe, you may be able to remove damaged concrete, clean and replace rusty steel, and fill in cracks. In cases of chloride contamination in buildings near the ocean, specialized repair work may be necessary. Once the underlying steel and concrete have been repaired, they must be properly cured with specialized coatings.
Waterproofing and comprehensive sealing after repair are important to minimize the risk of future concrete cancer in the building. Flat concrete roofs are particularly vulnerable to leakage and water-driven cancer if not adequately waterproofed.