The most troublesome and difficult problem when approaching the repair of an exterior wall system is the interface between the fenestration and the wall system. Typically, should there be leakage through the joinery of the fenestration, that leakage will seek evacuation through the wall cavity, unfortunately to the destruction of the existing sheathing or building components. Unless a continuous integration between the flashing at the sill and the water-resistive barrier is maintained, this leakage is not controllable, since it cannot be determined on which side of the water-resistive barrier this liquid water travels. Consequently, fenestrations are replaced on a regular basis, but the replacement installation is usually no better than the original installation, and relies totally on the integrity of the fenestration’s joinery. In addition, the wall itself can leak, thus causing leakage on the perimeter of sealed window openings.

This presentation will highlight novel approaches to install fenestration in drainage walls and masonry barrier walls. Testing compared performance of traditional techniques versus new techniques that include coatings, waterproof sills, and waterproof receptors. The testing investigated performance of the walls independent of the windows.

The completed installations prevent failed window joinery from leaking into the wall, by directing all water to the exterior surface of the cladding. The receptor allows for future replacement of the window, should it either fail or need to be upgraded to new energy-efficient technologies not now known, without a destructive removal and replacement process. The new window will take only minutes to remove and be replaced.

Presented at Thermal Performance of Exterior Envelopes of Whole Buildings X – December 2007

Units: I-P