Clear Water Repellent Treatments (cont.)
Benefits
Selecting concrete masonry as an integral part of the building's appearance provides numerous benefits for the designer and the owner. Where the gray color of standard cementitious products might provide a cold appearance, use of integral colors gives concrete masonry a warm appearance. The multitude of concrete masonry textures available provides an almost infinite variety of possibilities for building design. And, cost is typically competitive with other types of construction for many buildings.
Applying a clear water repellent treatment to concrete masonry can maintain the appearance of the concrete masonry while providing protection from water intrusion. Additionally, most clear water repellent treatments will keep the concrete masonry looking cleaner longer since a lower permeability prevents dirt from being drawn into the concrete masonry with the water.
Design
Projections and Sills. The cells in concrete masonry construction, and the need to maintain alignment of the cells for reinforcing, limit the tendency of designers to create additional patterns by extending some units beyond the face of the wall. Although this process is possible with concrete masonry, the problems of increased water absorption and penetration through the exposed horizontal surfaces should be considered.
Most clear water repellent treatments are not designed to resist water penetration on horizontal masonry surfaces. Accordingly, ledges formed by projecting units out beyond the face of the wall should be either flashed with sheet metal or patched with an elastomeric coating (see Figure 1).
Dense, precast concrete sills, properly sloped and with drip edges, can provide an acceptable sill condition (see Figure 2). Masonry unit sills should also be coated with an elastomeric coating. Avoid mortar sills since they are porous and crack. If used, they should be covered with flashing or coated with an elastomeric coating to prevent water.
Figure 1: Ledge Detail
Figure 2: Sill Details
Angelus Block Co., Inc. supplies this information as an educational aid in understanding the benefits of concrete masonry construction and our products. It is the responsibility of the user to obtain engineering or other advisory services from licensed professionals as the basis for incorporating into any project any information, detail, or product offered herein.