If you want a job for life, it could be painting the Sydney Harbor Bridge; once you’re done, you’ll probably have to start at the other end again. The paint goes on to prevent the steel from corroding, and the corrosion of the steel is what causes concrete rot, also known as cancer or concrete spalling.
How does concrete ‘burp’?
Concrete is used in most commercial and residential buildings in a variety of applications such as slabs, stairs, posts and columns, support beams, balconies and terraces, walls, pathways, and swimming pools. Large volumes of concrete are involved in structures such as bridges, piers, and high-rise towers. Concrete is generally reinforced with steel bars or mesh and in larger developments significant amounts of steel are required for added strength.
The enemies of reinforced concrete are water and air. If these elements gain access to the steel encased in the concrete, it can corrode: the steel expands as it breaks down and fractures the surrounding concrete. As the concrete cracks and crumbles, there is an even greater opportunity for water and air to come in contact with the reinforcing steel and the process is intensified. There are obvious safety concerns as the structural integrity of concrete is reduced.
How to identify concrete rot
It may be going on invisible within the concrete, but as it continues it becomes more apparent. You may notice rust marks running through the concrete, or the concrete flaking, cracking, or crumbling. In extreme cases, large sections of the concrete will fall away, exposing rusted reinforcing steel. Remedial treatment may involve substantial and costly corrective measures.
A professional building inspection can identify the problem or warn of possible future problems. It could be water pooling somewhere, small cracks in the concrete, or reinforcement too close to the surface of the concrete. Certainly, it’s better to be safe than sorry with concrete rot: it may simply be a matter of improving drainage, painting a surface, or sealing cracks with some sort of mortar or epoxy filler. If you have any concerns about concrete rot, it’s worth getting expert advice.
I like to be by the sea
Well yes, most of us do, but this is where concrete rot can be even more prevalent as chlorides in moist, salty air react more aggressively with reinforcing steel. Concrete rot is an ever-present problem in locations near the sea and owners need to be constantly on the lookout for any signs of deterioration and ensure protective measures are maintained.
The same can be said of the chlorides associated with the chlorine in swimming pools or saltwater pools.
In addition, there is often moisture near the soil surface in beachfront blocks, and water can wick into the structure. Large buildings with basements or underground parking garages can experience the same problem with groundwater seepage.
In short, concrete rot is a common problem. It can cause significant structural damage that can be difficult and expensive to repair. It is not always easy to detect, can have serious safety consequences, and can be avoided with expert advice and the use of the correct materials and proper construction guidelines.