IN RECENT YEARS, A WIDE range of new flashing materials has entered the home building market. The NAHB Research Center and Williams Building Diagnostics, on behalf of the national Partnership for Advancing Technology in Housing (PATH), is surveying these innovative new products and describing the ways they can be used to reduce water intrusion in modern homes.

Technologies being evaluated in the field and the laboratory include elastic and pre-formed pan flashing systems. Each test installation will be subjected to extensive water-spray testing and then evaluated to determine the nature and extent of any water intrusion that occurs. Analysis techniques will include thermal imaging, runoff volume collection, and extensive use of moisture sensors.

To determine why water has intruded during the test, Diagnostics' engineers will evaluate cases in which water intrusion has occurred at the window-to-wall interface. Field test results will be used to refine concurrent laboratory testing activities so the flashing techniques studied reflect real-world conditions.

The PATH program will issue a report in summer 2005 that identifies both the best practices for window sealing and new technologies that improve the effectiveness of the building envelope. The report will also describe methods for improving the uniformity of installation practices and reducing labor costs as compared to traditional technologies. The information will be available at