Painting Concrete

Question:

I am looking for a product that will effectively adhere to cement under tough conditions. This coating will be subject to steamy boiling water. There is an expansion joint as well as the cement that must be covered and protected.

The area is relatively small, 77 × 142 inches. There is a boiler sitting in this area. I need to coat the surrounding area without moving the boiler. Is there a product available to me that will suit my needs? J.F.

Answer:

Painting concrete can be an enlightening experience. I usually don’t recommend it. I don’t like to paint brick buildings either. When I had a real job, I was forced to recommend the white material used to paint the red brick buildings at the Westinghouse Research Labs. My greatest nightmare was seeing the paint coming off the building in large block letters spelling IZZO.

Acrylic latex paints work well on concrete buildings. However, they may not be able to withstand the heat and moisture associated with a boiler room. A two-component epoxy floor paint may be as good as any for that application. One of your problems will be to prepare the surface. Oil and grease must be removed. This can be done using an aqueous detergent solution. The cleaning will disturb the concrete, and it may become as alkaline as fresh concrete. Therefore, after degreasing, the surface should be neutralized using an aqueous muriatic acid solution. After the concrete is dry, apply the epoxy floor paint in accordance with the supplier’s recommendations.

As far as the expansion joint, if it is flexible, the epoxy will be too rigid and crack. Instead, a flexible polyurethane coating such as that used in automotive applications on flexible body parts should be applied.