I am an architect in the north central United States where freeze/thaw conditions are severe. What should I ask brick suppliers in order to ensure that my clients obtain durable brick?
In freeze/thaw environments, a Grade SW brick should be used. This is defined in ASTM C 216 for face brick, ASTM C 62 for building brick, and ASTM C 652 for hollow brick or units in which the cores make up more than 25% of the gross area. Ask the brick supplier to provide certified test reports from the brick manufacturer, no more than one year old and preferably executed by an independent testing laboratory, attesting that the units tested meet the appropriate ASTM specification. The testing should report compressive strength, 24-hour cold water absorption, 5-hour boil absorption, and the saturation coefficient at a minimum. Most brick test reports also show values for the initial rate of absorption and results of efflorescence tests. Glazed brick are more susceptible to freeze/thaw deterioration than other units. When glazed brick are used, careful detailing and construction to prevent water penetration are essential. A vented air cavity behind the glazed brick also is needed to dissipate moisture. Otherwise, water can be trapped within masonry walls for long periods of time. I also recommend using glazed brick units that meet Grade SW requirements and have a maximum saturation coefficient of 0.78.