Our team gets asked all the time about why floor coatings fail. Sometimes it’s for a garage floor that was painted with a big-box store’s epoxy kit. Other times it’s a commercial service garage where the epoxy just won’t stick. The reasons can vary, but I’m going to attempt to describe the most common reasons why epoxy coatings fail (this will typically hold true for other types of coatings such as polyaspartic or polyurea).
Improper Surface Preparation
Too often, an epoxy paint kit from a big box store will instruct the DIY user to just clean the floor or etch it with muriatic acid. Cleaning along is NEVER enough. Acid etching, while a valid preparation method, will only work if the concrete’s pores are open enough to allow the acid to react and remove the laitance (the thin cement paste on the very top). Acid etching will also not suffice for areas of the concrete which are sealed, oil stained, painted or contaminated (with wax, tire shine or other chemicals).
To ensure a proper concrete surface profile (CSP 2 or 3), we normally utilize our shrouded concrete grinders. On rare occasion, we may also shot blast the concrete. For more information: Epoxy Floor Coatings: Concrete Surface Profiles Explained