The Challenges of Painting Concrete Block

calander Sep 28 , 2020 user-iconAnderson Painting
Anderson Painting concrete painting services

There are many reasons to build a property from concrete block. Concrete is relatively cheap, highly durable, and can hold plenty of weight. This material isn’t without its flaws, either. In particular, the porous nature and coarse texture of concrete can get in the way of an easy paint job. That said, painting over concrete block isn’t impossible -- it simply requires the right preparation, technique, and paint type.

Here are some challenges of painting concrete block and how to overcome them.

The Most Common Concrete Painting Problems

Concrete Block “Breathes”

Porous materials like concrete, naturally expand and contract as temperatures fluctuate. When these fluctuations are severe enough, the material can undergo thermal shock, wherein different portions of the material shrink or swell at different rates, often resulting in fracturing and other forms of damage. Certain types of paint, such as epoxy concrete floor paint, are designed to minimize the effects of these temperature changes. When painted concrete block undergoes thermal shock, the paint itself is often the first entity to break away from the surface. In other words, an otherwise perfect paint job can blister and/or peel away as things heat up or cool down too quickly.

Moisture Intrusion

Temperature isn’t the only factor that affects concrete and its paint job moisture can be a problem as well. Water has a way of entering any hole, crack, or crevice it can fit into. So, the pores and cracks present in concrete block provide a prime opportunity for moisture intrusion. Just as the proper paint job can minimize concrete thermal shock, epoxy paint for cement floors (and walls, ceilings, etc.) can protect these surfaces from moisture intrusion as well. These coatings seal the concrete’s pores, keeping small particles out, including not only water but also dust, bacteria, fungi, and more. Still, water (and other materials) can weasel its way into painted concrete. If this occurs, the paint can actually keep the moisture in, not allowing it to evaporate. Looking for an escape, the moisture can cause the paint to bubble and disadhere from the concrete.

Paint Absorption

If you’ve ever tried to directly paint a porous surface, you’re probably familiar with the paint’s propensity to soak into the surface rather than coat it. While it’s true that concrete paint is meant to seal the material’s openings, it’s also supposed to provide an additional layer of protection. For this reason, it’s important to initially seal and then prime the concrete block before painting it. Taking these steps allows the final coat of paint to properly adhere and protect the surface while offering a smooth, even finish.

How to Properly Paint Concrete Block

Whether you’re looking to apply epoxy floor paint for your concrete floors or coat your concrete block walls, the same basic prep work is required. The concrete must be thoroughly cleaned so all dirt, dust, debris, grease, etc. is eradicated from the surface. If the concrete was previously painted, all traces of old paint should be stripped away using a wire brush, scraper, and/or power washer. After the concrete is clean, dry, and bare, it’s time to seal and prime it with products meant for masonry applications. Then it’s finally time to paint the concrete block with the proper coating elastomeric/masonry paint is typically your best bet here.

There’s a reason concrete has been used for centuries. Unfortunately, painting this material can be a bit of a pain. If you need help coating your concrete block surfaces, applying epoxy floors, etc., the experts at Anderson Painting are here for you. To learn more about us and all we do, call today at 919-610-1855 or email us at!

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