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<br /> <br />off in various places. After 8 years of service, coatings 5 and 8 showed no <br />signs of cracking or loss of bond. <br />One type of material (coatings 4, 5, and 7) was so impermeable that it <br />kept water completely away from the wall. The other type of material (coat- <br />ings 6 and 8) contained some agents which seeped into the voids of the mortar <br />joints and reacted with the cement causing expansion and a filling of the <br />spaces. One cementitious coating of each type (coatings 5 and 8) showed long- <br />range success after 8 years in the climate at Vicksburg, Mississippi. <br />Material 5, which was formulated by the author at WES, (Figure 47) was a <br />coating with excellent impermeability and bond characteristics. The darker <br />material (pigment added) in this photograph is coating 5. Pigment can be used <br />to make the cementitious coating the desired color. For the maximum head of <br />water tested (4 ft), coating 5 sealed the brick wall from both the positive <br />and negative sides of the wall. This coating was less expensive that the pro- <br />prietary products and would be excellent where a surface coating is required. <br />Coating 8 was as successful as coating 5 and also sealed the brick-veneer <br />wall against 4 ft of waterhead from the negative and positive sides of the <br />wall. Coating 8 seeped into the pore spaces of the mortar joints; it was <br />observed to penetrate the joint and collect as a film on the opposite side of <br />the wall. Initially, the brick-veneer wall leaked a small amount, but as the <br />material seeped into the pore space, the leakage stopped. <br />The other three coatings initially caused the brick-veneer walls to be <br />impermeable to water when applied to the positive or negative side of the <br />wall, but they were not durable and failed with the passage of time. <br />Epoxy coatinKs <br />Two epoxy coatings (coatings 9 and 10) were used to seal the brick-veneer <br />walls. One epoxy coating was 100 percent solids. In each case, the wall with <br />the epoxy coatings leaked excessively. <br />Polyurethane coat inKs <br />Polyurethane coatings were not effective in keeping the wall from leak- <br />ing. If moisture collected between the polyurethane and the wall, the coating <br />turned a milky color. After approximately a year of exposure to the elements, <br />the polyurethane coating began to crack and peel from the wall. <br />Asphalt coat inKS <br />Asphalt coatings were not effective unless excellent workmanship was used <br />and even then there were possibilities of leakage. An asphalt coating is <br /> <br />53 <br />