Effective weather resistive barriers (WRB) perform important functions in retarding waterentry into walls and in controlling water vapor movement as well as the amount of energyattributed to air leakage (Burnett, 2000; Weston et al 2001). Recognizing this, a public andprivate sector research consortium was established to develop reliable and precise methodsfor evaluating their performance.This paper, third in a series, provides an overview of the most significant results obtainedduring the consortium work.
Field measurements and numerical simulation were used to measure moisture transfer to the building envelope for a building with and without a vapour barrier. The results indicated that the vapour resistance of the barrier can be significantly below that provided by polyethylene, even in cold climates. States that moisture transfer from indoor air to the envelope can be seen as improving the indoor air quality by moderating the indoor humidity.