Concrete Surface Preparation
Is it Important ?
Proper surface preparation is simply the most important part of installing a flooring system on concrete. This is the primary reason for DIY floor failures. Cleaning and repairing the surface is extremely important and acid etching or pressure washing is often not sufficient to create the cleanliness and the surface profile (roughness) required to have a long-lasting floor coating.
Grinding
Advanced Concrete Coatings as well as other professional floor installation companies use commercial grade concrete grinders to remove surface dirt, defects, and to create the correct surface profile as defined by ICRI and as required by the various chemical manufacturers' datasheets. Grinders use sacrificial diamond grinding pads to cut through the tough concrete surface. The pads come in many different styles and grit ratings. It takes experience to know which pad type to use based on the materials that need to be removed from the surface.
Crack and Spall Repair
Moisture Testing
Spalls are areas on the concrete surface which are damaged for various reasons and are similar to craters on the moon surface. Areas of missing concrete where the surface may have endured a hard impact or the original surface did not cure properly. These spalls, in addition to cracks, must be filled in order to hide them from showing through the new coating. Also, repairing these defects helps to stop, or at least slow, the further propagation of damage around the area. An array of modern fast curing polymeric materials are available to fill these defects prior to installing a new floor coating. Before selecting a repair material the environment of the concrete must be considered as well as the coating type that will be applied. Outdoor concrete may be exposed to large temperature variations as well as rain, snow and salt. There are lots of tradeoffs one must consider. For example, choosing a slow-curing flexible crack filler material may provide a better solution than applying a hard inelastic fast-curing material. It's important to pick an installer who can make such decisions in the best interest of the customer.
Concrete is porous and transmits moisture from the ground below. It's important to test the moisture levels of the concrete before applying any coatings. High moisture levels combine with salts in the concrete to attack the bonds between the concrete surface and the coatings. If high moisture levels do exist, then a moisture vapor barrier (MVB) may be required to prevent delamination of the coatings. MVBs typically add a bit more cost but are effective at mitigating future problems. Advanced Concrete Coatings tests every concrete substrate for moisture.