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The Most Common Concrete Cancer Causes

Concrete cancer is one of the most serious building issues which can potentially cause a building’s structural integrity to fail if left undiagnosed and unremedied. Because it usually starts out as a rust stain, most people immediately assume that the problem is a superficial one, when in fact, it is something that you needs more immediate rectification.
There are many causes of concrete cancer and if you own an apartment in a complex with any signs of concrete cancer, it is crucial you address them before it's too late. Workmanship, the kinds of materials used in construction, the environment where the structure is built, and the age of the building all play a role in this type of structural issue. So if you are keen to learn more about how to spot the tell-tale signs it's time to read on.  

The Problem is Not in the Concrete (No, it isn’t)  

If you’re familiar with concrete cancer, you already know that it is called such because the damage created by it is evident on the surface. But in reality, the problem in concrete cancer isn’t really in the concrete but rather in the steel reinforcement enclosed in cement. You just can’t see it with your naked eye. 

The truth is, even though the concrete should form what is a solid mass around the steel, concrete is penetrable; a simple crack from machinery, a bubble leftover from the pour, or a number of other factors allows water into the concrete where it absorbs chemicals from the cement which then react with the steel.
And if you are near the ocean, then the situation is likely to be worse. As you may or may not know, saltwater speeds up the process of corrosion, thanks to the faster flow of electrons that carry chloride ions, which in turn reacts to form rust if oxygen and moisture are also present in the environment.  

Now why does the surrounding concrete become cracked if the problem is internal?  

Once the steel loses electrons and begins to rust, it basically “swells” (up to 5 or 6x its original size). As a result, the surrounding concrete breaks and begins to crack because of the unintentional enlargement of the affected steel.   The cracks and some orange stains around the concrete are two sure signs that your building is afflicted with a serious structural issue.  

But what really causes concrete cancer? 

Ok, so now you know what the issues, are but what are some of the most important factors that contribute to the development of concrete cancer? 


Buildings built near a form of water are more prone to corrosion than those erected on dry land. Structures that are also constructed in places with humid and rainy weather are more susceptible to corrosion due to the moisture in the air. As mentioned above, along with oxygen and iron, moisture is elemental in the formation of rust. When the chemical reaction of these three is not controlled, the process will continue to affect the metal and further damage the concrete surrounding it.  


Poor construction work can also influence the prevalence of concrete cancer. For instance, if the concrete surrounding the reinforcement bar hasn’t been properly sealed or there’s just not sufficient coverage around the rebar, the propensity of water seeping through the slab is likely. Once water gets in contact with structural steel, you know what will happen next.  
Substandard waterproofing is another cause of spalling. If the membrane coating designed to protect flat surfaces from excessive damp proves to be inadequate, the lack of water resistance will expose the foundation to corrosion and chipping, or worse, cracking. 

Materials Used 

The quality of construction materials can potentially add to the threat of rusting. The type of cement, for example, must meet relevant standard specifications and must be appropriate for the type of environment where the structure will be built. Similarly, the type of aggregates must also be considered to ensure that the concrete mix is ideal to strengthen structural integrity and also be selected as to minimize the chance of chemical reaction in the environment.
Aside from that, the reinforcement bar and the concrete must be compatible with each other. Using a type of steel with a different thermal expansion and contraction rate will definitely stress the concrete, increasing its susceptibility to corrosion.   


Ordinary wear and tear, when left unattended, can contribute to concrete cancer. As we all know, slabs are subjected to regular load. If at some point, the weight becomes excessive and the concrete can no longer tolerate it, the foundation gets stressed out thereby fracturing some portions of the slab. The exposure then allows for moisture and water to reach the rebar, which creates a good recipe for rusting.  
If your building is already old, its chances of getting concrete cancer also increases because as a structure ages, the quality of the foundation deteriorates.  

What to do when your concrete has been compromised 

It’s easy to spot the symptoms of concrete cancer. From the flaking and chipping of the slab, to the occurrence of orangey stain on the surface, you can immediately tell if your building’s structural demise has started. But even if you can see the signs yourself, we highly discourage you from diagnosing the problem on your own and simply resolving the issue based on gut-feel.  
In all cases, we recommend that you call us or a qualified structural engineer to give you a detailed analysis of your building’s current situation. A proper diagnosis will help in the development of the most appropriate solution for your structure.  
If you are suspecting that your building is suffering from concrete cancer, why not speak to one of our experts here at Remedial. We have the proficiency in diagnosing and making the right concrete cancer repair approach specific to your problem.          

This blog was posted in Concrete cancer, Maintenance, Structural repair

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