April 2006
Water intrusion in building walls is an ongoing problem for the homebuilding industry. Intrusion can occur in all types of buildings and in most climates, often through windows, doors and other through-the-wall penetrations.
One of the most critical areas for water intrusion is below window units in typical wall assemblies. This area is often poorly addressed, detailed, and executed. To mitigate water intrusion problems, manufacturers in the past few years have introduced numerous new flashing products for homebuilders.
This project focused on managing water intrusion in residential building envelopes with a combined pan flashing/sill protection strategy. It also included a survey of all available pan flashing products, and laboratory and field evaluations of various pan flashing systems used with wood framing and sheathing.
Williams Building Diagnostics Inc. (WBD), a participant in PATH Field Evaluations, worked as a subcontractor to the NAHB Research Center (Research Center) for this study. WBD conducted the survey and the laboratory and field evaluations under direction from the Research Center.
Prepared by:
Williams Building Diagnostics, Inc.
37 pages