Curing Compounds ? What are they? Should you use them? A curing compound is something applied to a newly poured concrete slab or other type of installation for the purpose of creating a harder, better finish. The way they work is to slow down the drying. That prolongs the "hydration process" of the chemical reaction that is between water and cement. Slowing it down gives it a longer time to react and creates a higher ultimate strength. This is true. Construction techniques used to slow down the drying are: Covering with a wet fabric Covering with paper Misting periodically with a fine water spray Applying a curing compound Typically, a curing compound is a low level sealer. This sealer creates a light coating that slows down the water evaporation. However, it also has put something on the surface that can cause problems when applying a final, high quality sealer because it is in the way. Unfortunately, sometimes a manufacturer of some component for an installation will recommend the use of their proprietary "curing compound" as a way to increase sales. It may help with the ultimate strength of the project, but will create other problems for protective sealing later by interfering with the penetration and bonding of the final sealer. For this reason, Aldon is not in favor of the use of "curing compounds". The other techniques are preferable. If this has been done on your project, treat is as though the project has had a sealer applied. Even if the "curing compound" (sealer) is of such low quality that it appears to be gone. See for "Redoing a Previously Sealed Surface" because that is what you have.   (If you entered the site on this lower level page - click here to go to the top level home page.) .