Field Evaluation: Williams Building Diagnostics, Inc.
Final Report April 2006
There were two field tests of existing buildings in which substantial moisture damage had been repaired-a two-story residential house and a small-scale commercial building. Both buildings were repaired using pan flashing integrated with weather resistant barriers. To augment the field tests, laboratory mockups were constructed to test weather-resistant barriers and pan flashing systems:
For the specific products and conditions evaluated in the study, pan flashing demonstrated the potential to greatly improve the moisture resistance of the window/wall interface.
In both the laboratory and the field tests, the pan flashing systems effectively prevented the intrusion of water into the wall cavity at the window sill.
The different weather-resistive barriers (WRBs) and installation techniques tested on the panels in the laboratory also resulted in no water intrusion, demonstrating the systems’ durability over a wide range of weather conditions.
No water intrusion was recorded at either field site after remediation with pan flashing and weather resisitive barrier techniques.
For best results, builders should slope the sill pans, or use products with an integral slope, to ensure that water does not reach unprotected wood, and that it also drains away to the exterior of the wall.
Monitoring of the two field sites is ongoing.