How to Fix Concrete Cancer?

What concrete cancer is, and waterproofing solutions to fix or prevent concrete cancer?

What is Concrete Cancer?

Concrete cancer is the breakdown of a building’s concrete, specifically in areas that surround internal steel reinforcements.

Concrete cancer occurs when water makes contact with the structural steel reinforcement bars and causes rust. The steel bars then forcibly expand and deform, breaking apart the concrete that surrounds them. The concrete ‘spalls’, i.e. breaks apart and falls away in chunks.

Buildings are often required to ‘encase’ the steel rebar with specific types and depths of concrete. This serves to shield the steel from the elements, which may include varying levels of rain and/or salt (if near the ocean). However, concrete, no matter how thick or what type, remains a porous substrate. Water likely will eventually soak through to the steel within, and concrete cancer will then occur in time. However, there is a way to prevent or treat it before significant damage is done.

How to Repair & Prevent Concrete Cancer?

Concrete cancer, and other similar problems like efflorescence, can be treated or prevented. Chemical water repellency can be added to the concrete surface itself by means of applying Resistain, a waterproofing sealer.

Resistain is an advanced liquid waterproofing sealer that is applied to concrete surfaces using a brush, roller or spray. It soaks into the concrete to a depth of 10mm, binds with the structure of the concrete in a molecular level and forms a water-repellent barrier. Once Resistain is applied, the concrete surface itself will repel water and salt. This protects the surface from all forms of water damage, including concrete cancer, efflorescence, mould, algae, discolouration and weather-based erosion.

Resistain will also reduce staining by various causes, and will also repel oil.

How to Treat a Surface Using Resistain?

A thorough guide to waterproofing concrete and other surfaces is available here.

Equipment

Preparation equipment:

• Concrete cleaning equipment
• Concrete gap-filling or crack repair equipment if needed.

Application equipment:

• Resistain penetrating sealer
• Brush, roller or spray for applying Resistain
• Cloths or rags to wipe up excess Resistain.

Method

Prepare the surface to be treated by cleaning any dirt, grime, mould or foreign matter from the concrete.

If there are any gaps in the surface, these need to be repaired so the concrete surface is unbroken before applying Resistain.

Using your preferred application tool, apply an even coat of Resistain to the surface. The surface should have a mirror-like appearance.

After the first coat is absorbed into the concrete, apply a second coat.

10 minutes after the second coat, wipe away any remaining liquid that will not soak in. If the surface is still soaking in Resistain, another coat can be applied as concrete is highly porous.

The surface will be water-repellent as soon as the treatment soaks in, however the full curing process will take up to a week.

Use isopropanol or a dry cloth to clean Resistain off the equipment or other non-masonry surfaces.

Conclusion

Resistain will maintain the surface for a minimum of 15 years. It can be reapplied at any time.

Surfaces already experiencing water damage, and surfaces which are as yet undamaged, can be treated. It is recommended to use Resistain as a preventative measure.