The Importance of Integrating Flashing and the Water Resistive Barrier in the Exterior Wall Systems of Residential Buildings

Building science studies have recognized the importance of the proper installation of flashing and its integration with the water resistive barriers as very important to the success of a wall assembly. The roll of flashing is to direct water away from the opening to the water resistive barrier, which in turn directs the water to the exit point in the wall. The integration of these two elements and the quality of their installation is ultimately important to the success of the wall system. It is equally important to select products, which perform as intended after installation. Extensive testing has been conducted on local and regional methods that do not follow the guidelines in E 2112. When tested, many of these installation methods completely fail to perform the required function of preventing water leakage. Conclusions are that it is important to follow E 2112 in installing flashing and integrating it with the water resitive barrier (WRB). It is equally important that a WRB is used. Each element of the installation is important. If the flashing is perfect, but the WRB lets water through, then there are potential problems.