Mend The Un-mended: How To Prevent & Repair Spalled Concrete

Did you ever find it irritating that your once beautiful concrete house walls were now crumbling and starting to flake off? It is slowly ruining the appearance of the house. Well, there is no effect without a cause – just like almost everything in the world. So when it comes to this, we can either prevent it from happening or we can prevent it from worsening. Concrete is one of the materials that is easy to get spalled if its thickness is not measured properly. For that reason, many concrete contractors use coating thickness gauge to measure concrete coating thickness to make sure they can prevent spalling or any other type of damage from damaging the house or building. If you are experiencing the same problem or looking to prevent it from damaging your house, then you are in the right place because in this article, I’m going to tell you how to prevent and repair spalled concrete. Keep reading to find out!

Before we start, let’s talk about spalling first. What is spalling, actually? Spalling is the result of water entering brick, concrete, or natural stone. It forces the surface to peel, pop out, or flake off. It's also known as flaking, especially in limestone. In concrete, spalling happens because of moisture in the concrete. Moisture (often salt too) will usually push outward from the inside, especially in basements. If not properly treated soon, spalling can eventually cause crumbling and destruction of a structure. There are mainly 3 causes of spalling and sometimes a combination of these causes. First, it can be caused by salt that is used on frozen roads. This can cause oxidation or rusting of reinforcing steel when it is often in contact with a surface or building. Curing process or the way the concrete hardened can also cause spalling. Also, alkalis in the concrete mix and carbon dioxide in the air can interact and force cracking, admitting water in the process.

How to prevent spalling

There is one technique that can prevent concrete from spalling; it’s by using a good water sealant applied to the finished surface. This can prevent water from entering into the concrete. You can also avoid spalling if you manage the concrete carefully and use proper techniques when it is being poured such as preparing for adequate concrete cover (embedment) of rebar and placing joints at the right locations with the right distances. Make sure you observe the edges and corners of exposed concrete so that you reach adequate concrete cover, as specified by the structural engineer.

How to repair spalled concrete

The ways to repair spalled concrete may vary and it depends on the severity of the problem, the location and type of concrete structure as well as other factors. However, you can do it these ways:

1.  If the spalling damage is shallower than 1/3 of the concrete’s thickness, you can treat the concrete with surface repair. However, if the damage is greater than 1/3 of the depth, you might need to install steel bars with a full depth restoration
2. You must clean corroded rebar since it is vulnerable to exposure. Clean it at the beginning of the restoration process. Once it is cleaned using a wire brush and all types of corrosion is thoroughly removed, you should give the rebar a protective coating of rust inhibitor to reduce future corrosion
3. Make sure all the repair materials should have an expansion coefficient that is similar to the one of the original concrete
4. If the damage is on walkways, driveways and other horizontal surfaces, you should repair it with a cementitious overlay. When it is set completely, you can apply a waterproofing membrane in order to prevent spalling from recurring.

While repairing concrete may be a tough job since it requires many tools, props and preparations, you can always avoid this problem from occurring by doing complete measurement methods. Why? That’s because through measuring, whether it is measuring paint thickness, concrete thickness or other parts needed to be measured, you will know the right amount of substance and even materials you may need to build your place. When you use the right amount, you will do the right method to prolong the strength of your building.