Follow these four steps to ensure good results when you need to coat concrete when it’s cold.
1.Use elastomerics for thermal movement
If a coated concrete wall is expected to withstand an unusual amount of thermal movement, elastomeric coatings will help to accommodate that movement and continue to provide a consistent protective film. Coating products that prevent the ingress of water into the concrete surface can also help protect against freeze-thaw damage.
2. Remove chemical residue
In cold climates, vertical concrete in parking garages or adjacent to streets, sidewalks or parking lots can be exposed to de-icing salts or other chemicals that leave a residue on the concrete surface. It’s important to remove this residue before applying any coating. You can remove most salts by water washing, but address any other chemicals specifically, based on their composition.
3. Don’t add solvents
Temperature also has an effect on coating application. All coating materials change in viscosity with changes in temperature. Colder materials thicken and become more difficult to apply, while material applied to a structure that is very hot or in direct sunlight may dry too fast, fail to adhere properly and produce an undesirable finish.
Given today’s construction demands and fast-track scheduling practices, it may be tempting to add water or other solvents as a way to enable application and therefore extend the work day or season. Resist the temptation, though, because manufacturers don’t anticipate these additives when formulating coating products or testing their performance.
4. Make sure the surface is dry
You should also make sure any water that was part of the concrete mix during placement (or was introduced by weather or surface preparation procedures), is allowed to evaporate before you apply a coating, so that the material can properly adhere to the surface.
Also, even though some solvent coatings can be applied to surfaces below 32 degrees Fahrenheit, take care during the colder season not to apply coatings to concrete that might contain ice that will eventually thaw and affect adhesion.
Learn more about coating concrete in our companion articles:
- The Best Coatings for Concrete in Cold Climates
- Coating Concrete When It’s Cold: What You Need to Know
This article was originally published in the Winter 2016 issue of the Sherwin-Williams CommercialPro newsletter. Get more business-building tips and info on products, services, discounts and project solutions on the Sherwin-Williams contractor website.