Who's the Culprit in WRB-AB Leakage?

摘要

Extreme weather events can stress wall assemblies, causing water to enter the building envelope. Fasteners attached through sheathing are a point of vulnerability requiring specific attention in order to avoid leaks and compromising building integrity. With some minor exceptions, the standardized test methods for water-resistive barriers (WRBs) and air barriers (ABs) do not consider the range of adhesive and mechanical cladding attachments. These standardized methods also do not include simulations of extreme wind and rain on the cladding attachment penetrations. In this course, we will examine parameters and outcomes of water penetration testing, specifically on cladding attachments using ASTM E331 methodology. The intent of this testing is to determine the ability to resist liquid water penetration of multiple attachment clips in three different WRB-AB configurations under varying conditions. The WRB-AB configurations include thin-and thick-mil fluid-applied barriers over glass mat gypsum sheathing and an integrated sheathing system, which integrates the WRB-AB into the fiberglass mat and core. Testing simulated extreme water and wind that pushed the tested WRB-ABs to the point of failure. The results demonstrate how the tested WRB-ABs performed with the main source of leakage occurring at the fasteners. Based on this information, best practices for addressing cladding attachment penetrations are offered under different scenarios and with specific climate and construction risk factors considered.