Performance Evaluation of Water Repellents for Above Grade Masonry

Water penetration across brick masonry exterior walls is a prob lem that building owners and construction professionals must deal with fre quently. Water repellents are often used in an attempt to resolve water penetration problems in certain remedial applications. Unfortunately, the information avail able to building owners and construction professionals regarding the use and evaluation of water repellents is limited. Little practical information exists to assist in the selection of such products and in the evaluation of their performance and durability. As part of a CMHC research project, Patenaude-Chiovitti Inc. carried out an evaluation of such products, exposing problems of performance evaluation of water repellents for above grade masonry. Six series oftests were conducted us ing a modified ASTM E-514 procedure and water uptake tube methods to evalu ate the performance of five commercially available masonry water repellents. The results of the study have indicated substantial improvements in the resistance to water penetration upon application of these products to clay brick wall assemblies. The data accumulated during this study may have also revealed a trend indicating an increase in the rate of water penetration from the time of product application (i.e., reduced repellency), necessitating product reapplication after a given time interval. Readers are cautioned in the interpretation of the test data without addi tional information pertaining to the vapour diffusion characteristics of the ap plied products and durability concerns.