The risks of Magnesite and Concrete Cancer

Let’s talk about magnesite. What is it, and why is it such a problem when wet?

Magnesite flooring is made of Magnesium Oxychloride. It has been used as a floor leveller, and was predominantly used in a lot of multi storey buildings across Sydney from the early 20 century until the 70’s, which aided the rapid growth and building of these structures. It is often a reddish brown appearance, and is relatively soft and flexible to the touch. Once wet, it often resembles the texture of a cork from an old wine bottle!

So why is it a problem when it gets wet though? For a start, Magnesite is extremely porous and absorbent. As a result, it will also leech chlorides into the concrete subfloors and any pipework within the slab, as gravity does it’s job and pulls the now contaminated water through the concrete subfloor. This means that the steel reinforcement of the concrete subfloor is at risk of corrosion and concrete cancer, which can cost thousands upon thousands of dollars worth of damage to your building. This is why it is so important that your flood restorer is familiar with this surface, and how to dry it properly.

Generally speaking, most magnesite can be between half an inch to one and a half inches in thickness. It will hold a lot of water, and the drying process takes a significantly longer time than just a regular concrete subfloor, as not only does the magnesite have to be dried, so too does the subfloor below. The drying process also has a tendency to show up any weak areas of magnesite, which can often present as cracks or separated sections which are not always apparent to the naked eye, but can show up with the implementation of a “drum” test.

Therefore, it is important that all floor coverings are removed from magnesite, not only for the drying process, but also to be able to expose any weak or damaged areas to be replaced with modern products such as Ardite.

For anyone living in a magnesite building, it’s always important to ensure that any building managers, strata, or body corporate members are familiar with the seriousness of what water damaged magnesite can present to the structure of the building. It is also recommend that anyone walking on exposed magnesite wear enclosed footwear, as the chlorides can also pose quite the irritant to sensitive skin.

FloodMaster are available 24/7 and are just a phone call away to assist you with your magnesite building.