One of the most common problems of concrete decks is the constant exposure to water. Due to its location and use, it is often subjected to moisture seepage that comes in a variety of form — water vapor, flooding, or liquid contaminants. Concrete’s porous surface allows moisture to pass through, causing slow structural deterioration. Furthermore, if the moisture comes in contact with the reinforcing steel underneath the deck surface, it can lead to corrosion and damage.
One type of protective deck coatings that may be applied to repel water from decks are known as sealers. Sealers are often made of silicon materials, although there are epoxy-based deck coatings that can be used. Deck coatings that act as sealers are applied to prevent water intrusion into the substrate. Because of these water-repellent abilities, sealers are more commonly used in exterior decks such as parking lots, where water is constantly present.
Unlike thick-film deck coatings, thin-film sealers do not form a barrier to prevent water permeation. Rather, sealers penetrate the concrete substrate and fill up every pore in the area. This makes it difficult for foreign materials such as water to penetrate. In cases when water does come in, sealers release this moisture in the form of vapor.
One difficulty in applying sealers is that it is often hard to estimate their effective coverage, especially since they are commonly spray-applied rather than brushed over the surface. The surface preparation does not need a rough surface profile. Cleanliness is the only thing that must be ensured, because any dirt, oil or grease can inhibit total penetration of the surface.