Use Enhanced Water-Resistive Barrier (WRB) Materials and Best Flashing Practices to Keep Water Out of Walls and Buildings.

Although a WRB and flashing details are required by the building codes, certain practices can increase their effectiveness in extreme wind-driven rain events. Under abnormal conditions, such as a hurricane or severe wind-driven rain event, quality of installation becomes particularly important because the consequence of any defects are magnified. Also, one can enhance WRB installation and flashing details following recommendations and resources cited in Chapter 4. For example, overlapping of joints can be increased (i.e., 4” instead of 2” lap) and joints sealed. Also, WRB materials can be more carefully selected by requesting full-scale assembly water-penetration test data from the manufacturer (not all WRB materials or assemblies will pass such testing).