Unique in their nature, these methods of construction are widely used in large industrial, commercial and office projects. Cast-In-Place and Tilt-Up construction specifies the use of solid concrete as the exterior substrate. Concerning pre-cast construction, large concrete panels, or wall sections, are either pre-cast at the factory or cast on site and then tilted up into their vertical position. Cast-In-Place also features a solid concrete wall surface, but instead of tilting up the panels, wood or metal forms which have been built around proposed wall areas are filled with liquid concrete and, consequently, the wall actually cures or sets-up in place.
Frankly, due to their density and absence of mortar joints, these substrates rarely leak except where they crack. Architects, therefore, rarely specify an exterior waterproof coating material application. They do, on the other hand, often specify exterior sealers, such as Combocrete Color-Lok KL-33, which act to protect the wall from staining. Moisture and rain will, of course, penetrate the substrate, but due to the density and thickness of the wall itself, will not travel into the interior of the building. There are, however, other considerations which must be addressed.
Although leakage will not occur, rain contains a number of airborne pollutants and penetration into the substrate will ultimately result in staining and efflorescence as the moisture escapes the substrate during the drying process. The application of Combocrete Kl-25 will prevent the intrusion of moisture and subsequent staining. Although water based, Combocrete Kl-25 has been formulated to penetrate denser concrete substrates.