A new ASTM International standard will describe in detail the design and specification process for water vapor transmission properties of water-resistive barriers and air barriers in building construction. ASTM’s performance of buildings committee developed the new standard, which will soon be published as E3127. ASTM International member Danko Davidovic says that the new standard will explain how WRB/AB systems perform in different wall and roof assemblies in various climates when the moisture migration by water vapor diffusion is taken into consideration. The standard reflects the best building science practices with regard to how water vapor transmission properties of WRB/AB impact … Read more