What is Concrete Dusting?

Concrete dusting appears on the surface of concrete that has not been mixed or installed properly. There are a number of causes of concrete dusting and just as many methods for preventing it in the first place. There are also ways to repair concrete dusting that has already occurred. This article will explain the basics of concrete dusting so that you know what to watch out for in your next concrete installation. It will also give you ideas for reducing the dusting effect that has already occurred.

What does Concrete Dusting Look Like?

Concrete dusting appears on the surface of the concrete. This is good news, since surface flaws are often easier to repair than those that run deeper into the concrete installation. Dusting looks like a powdery, chalk-like finish. It can easily be removed with a broom or even with your fingernail. It is most often seen on surfaces like driveways or concrete floors.

Why does Concrete Dusting Occur?

There are many possible reasons why concrete dusting occurs, but its presence is often indicative of a weakness of the wearing surface. Dusting can be caused by a finishing technique used while water bleed is still on the surface. The water mixes with the concrete, producing a higher water to concrete ratio than normal. Concrete dusting can also be caused by improper curing, excess amounts of clay on the concrete or exposure to elements before the concrete was fully cured. Inadequate ventilation can also be a culprit, particularly in closed quarters like basements. This environment allows carbon dioxide to build up and create a chemical reaction that affects the surface strength of the concrete.

How can You Fix Concrete Dusting?

Concrete dusting can be effectively repaired, although it is a good idea to first test the strength of the concrete fixture. To minimize the dusting effect, apply a chemical floor hardener to the surface. Choices might include metallic zinc, sodium silicate or magnesium fluosilicate. A professional concrete contractor can advise you of the best substance to use. In more severe cases, you may need to remove the surface layer, using a high pressure washer or sandblaster.

How can You Prevent Concrete Dusting?

Concrete dusting is best prevented during the installation process. Finishing techniques should never be used on concrete surfaces that have water on the surface. The building should be properly ventilated during installation and the surface should be protected from the weather as much as possible. It is also important to cure the surface of the concrete properly by using the appropriate curing compound and cover when necessary. By following proper installation steps, it is much less likely that concrete dusting will occur.

Concrete dusting rarely indicates a structural problem with the concrete, but it can be a troublesome problem, nevertheless. The best way to treat concrete dusting is to avoid it in the first place with proper installation. If dusting does occur, you can treat it with the methods listed above. If you have questions about your concrete surface, contact a professional contractor for more information.