There are two competing products in the garage floor coating industry: the traditional applied epoxy/polyurethane coatings, and the relatively newer polyurea coatings. First, the coatings are chemically related; they share a common chemistry.
Both coatings have remarkable adhesion properties, and are very durable, at least compared to typical paint products. Another introductory point is that although advertised as “polyureas”, garage floor polyurea products are really hybrids. A pure polyurea cures in 15 seconds or so–obviously not very easy to apply unless it is sprayed. Pure polyureas are sprayed, and used in industrial applications.
Strenghth and Adhesion
Adhesion is important because garage floors take a beating. If the adhesion between coating and cement floor fails, then the project fails. Both polyureas and epoxies adhere tenaciously to the surfaces to which they are applied-but only when the underlying surface is prepared well.
The problem with polyureas is that the reduced drying time may not sufficiently “wet” the concrete surface to which it is applied. This wetting of a surface means absorption, which means adhesion. We know that Premier Garage uses some form of hybrid, and the recent lawsuit brought by some of its franchisees involved, as one of its claims, allegations that PremierGarage’s hybrid products lack adhesion.
It’s only an allegation though, and I would suspect that the problem may lie in the surface preparation, rather than the coating properties. Here in Austin, the one Premier Garage installation I observed was prepared with an acid solution, and not with a physical grinder. That’s a recipe for disaster–the best preparation is always surface grinding.
All in all, polyurea hybrids and epoxy coatings, when applied over well-prepared surfaces, have more than adequate adhesion properties to adhere to even imperfect concrete for at least a decade.