Most deck coating failures are the result of inadequate preparation of the concrete substrate. In order to circumvent these issues, our Technical Service Department has compiled the following check list for avoiding adhesion problems caused by inadequate surface preparation.
Ensure that there is an adequate surface profile or anchor pattern.
Concrete is a porous, heterogeneous composite. Its pores or capillaries aid in the adhesion of the deck coating. Adhesion is improved via the use of high penetration primers, preferably of the lowest possible viscosity. The greater the depth of penetration, the better the adhesion will be. But concrete porosity alone does not produce an adequate surface profile.
Mechanical adhesion is also achieved in the concrete substrate by roughening or profiling the concrete. The minor peaks and valleys formed by roughing the concrete provide an anchor pattern to which the base coat topping can bond. This profile can be created by mechanical methods such as shot blasting or by proper finishing of the new concrete.
Be certain the concrete is sufficiently clean. The degree of cleanliness of the concrete substrate is critical for long-term adhesion. Surface preparation must product a substrate that is free of all deleterious substances. Substrate cleanliness means also that there are “non-visible” contaminants on the concrete. Job site tests may need to be performed to ensure soluble salts and other contaminants are not present. Water soluble contaminants can be effectively removed by using high pressure water jetting or other mechanical means. Curing agents or sealers can cause deck coating failures if they are chemically incompatible with the coating system. Solving this problem generally involves concrete removal via mechanical means.
Ensure that the concrete substrate is dry. Among the several tests for the presence of moisture in concrete, the most effective is the rubber mat or plastic sheet taped to the deck.
For more information or deck coating application and equipment recommendations, we urge you to contact our Pecora Corporation Technical Services Group. Our expert team is highly qualified to answer any question, recommend the proper solution, or provide testing training. Our Technical Services staff offers training in product technology and use and provides the technical assistance you require in the planning and implementation of your project. They can be reached by email firstname.lastname@example.org or by phone (800)-523-6688.