How Painting Prevents Spalling

Prevention and Repair of Spalling

Now in one of our more recent posts, we discussed how to properly paint parking garages to preserve the structures. In that blog, we discussed and ultimately defined spalling. Simply put, spalling is when the concrete breaks off into fragments. Today we will look at several ways we can fix areas where spalling has occurred and how to prevent spalling from taking place!

What Causes Spalling

Many structures are made of concrete. 95% of concrete structures have some sort of steel inside the concrete slabs. This makes up the floors and walls of the structure. As stated before, spalling is when concrete breaks up and falls apart from the inside out. This happens when the steel inside of the slab begins to rust  and swell as a result of the rusting. With no room to expand, the rusting steel pushes out on the concrete causing it to crack and break up.  

Repair: How To Fix Spalling

Many people do not realize that concrete is really nothing more than a hard sponge. By design concrete allows moisture to pass through it. Often the steel is coated with zinc primer to make it last longer, but even so, if moisture gets into the slab, at some point the steel inside will rust and spalling will occur.  The solution is costly. First the spalled concrete must be chipped away. Then, the now exposed steel must be wire brushed/shot blasted and then primed. Once the spalled section is repaired and the steel is prepped, pneumatic cement must then be applied.

Prevention: The Good News

However, prevention is a much easier process than repair. If the structure is coated with a good waterproofing system that covers the floors, walls, and ceilings the concrete or “hard sponge” will never get wet in the first place. Therefore, not allowing the steel inside the slab to rust. There are many high quality waterproofing systems that will get the job done such as Sherwin Williams Loxon XP or elastomeric paints, if an opaque coating is desired. Floors can be coated with a waterproof system, such as a urethane system. If a clear finish is needed, Floor Skinz Super HydroPhobic clear sealer is a great system that is completely invisible and has no sheen at all. 

The bottom line is, if you keep your concrete slabs caulked & coated properly, you should have little or no spalling issues.