A New Testing Method to Evaluate the Relative Drying Performance of Different Building Envelope Systems Using Water Trays in Stud Cavities as Moisture Source

Abstract

Abstract Due to defects in construction, design, and/or deterioration during operation, failure occurs where rain water penetrates into stud cavities of wall systems. Some wall systems tolerate this water intrusion better than others. A new test method has been developed to evaluate the relative capacities of different wall systems to dry out the invading water. In the test setup, the walls of a two-story test hut were made up of 31 wall assemblies (each 2.44×0.76 m2) of different configurations. The hut was erected within a large climatic chamber and subjected to a steady-state climatic loading for 288 days. Within each stud cavity, a water tray on an electronic load cell was placed on the bottom plate to provide a moisture source that represents water penetrating into the stud cavity and provides a consistent moisture loading from one specimen to another. Each wall assembly was instrumented with 25 gravimetric samples and relative humidity and temperature sensors/probes. Indexes were developed to indicate the relative performance of the walls.