Project Ref 1002

Magnesite and Concrete Cancer

Magnesite flooring was widely used in Australia from as early as the 1920s up until the early 1980s. With a cork like texture, this type of flooring was made by combining magnesium oxychloride cement with natural fillers. It was typically applied as a topping over concrete slabs or as a self-leveling layer, creating a smooth surface to support the installation of various floor finishes like carpet or tiles.

🔍 The Problem
Magnesite flooring can lead to concrete cancer if it becomes wet, particularly in areas such as bathrooms, kitchens, and at balconies. The material is highly susceptible to moisture absorption, which causes chlorides in the magnesite to seep into the concrete slab beneath. This leads to corrosion of the steel reinforcement, resulting in cracks in both the slab and flooring. Over time, this can cause the surface to become uneven, and tiles may crack or lift. Additionally, the structural integrity of the slab can be weakened.

💡 When to Act
Regular maintenance and repairs are essential for preserving the integrity of any building. Often, the full extent of underlying damage remains hidden until renovation work begins, potentially revealing cracks or delamination in the concrete slab. If the building has a history of magnesite flooring or noticeable undulations in the flooring, these may indicate a potential risk for the development of concrete cancer.