No Masonry is Truly Waterproof

By Gary Johnson

No masonry is truly waterproof, whether the result of capillary action, absorption or construction error. During the multi-decade life spans of typical high-quality structures, drainage in the cavity of a masonry veneer wall is necessary to minimize moisture damage and create a long-lasting, low-maintenance wall. Drying of the wall by promoting ventilation within the cavity is of increased importance, most recently due to the application of continuous insulation close to the exterior of the structure.

The impairment resulting from mortar dams of both water flow down to the weep system and airflow should be prevented. Specifying and installing materials that block mortar penetration while supporting water and airflow are important design considerations. A well-known answer to this issue is MortarNet®, developed more than 25 years ago. MortarNet is fabricated from a polymer mesh formed into a series of dovetails. Mortar droppings falling to the bottom of the cavity are captured at two levels, preventing the formation of a continuous blockage of the weep system. As a result, water and air are free to move through the device and within the cavity.

Adhered masonry veneers, such as manufactured stone, natural stone, stucco and thin brick, have the same moisture penetration and drying issues as brick veneer cavity walls. However, they have been slower to adopt proven moisture management techniques and continue to suffer from a high failure rate. DriPlane™ and WallNet® by Mortar Net Solutions are examples of polymer-based mesh products designed to create cavities behind adhered veneers to promote drainage and ventilation. This brings the same technical solution that has proven effective for brick veneers over decades to adhered masonry.