How to get a "no-brainer" air barrier system
Since starting this blog, many of you have asked how air and vapor barriers interact with the building envelope, particularly as they relate to below grade/blindside waterproofing and roofing. As the cliché says, the devil is in the details.
To borrow another cliché, one size doesn’t fit all when it comes to construction details. This is an obvious, yet important point because as construction professionals, we often try to fit all details into the same category. But think about it. A fenestration is not always the same in every building. On one building it may have an opening with steel studs, gypsum sheathing and a flanged window. On another, the fenestration may have steel studs, gypsum sheathing and a curtain wall assembly.
The same is true when it comes to air and vapor barriers. For example, choosing a fluid or sheet applied air vapor barrier depends largely on the building details. A cluster of pipe penetrations is more easily sealed with a fluid applied membrane than with a sheet applied membrane. A transition between two dissimilar materials is more easily sealed with a sheet applied membrane.
Tie-ins are crucial details to consider when deciding on the best option for keeping air and vapor out of a building. Most system failures occur at tie-ins so you have to get it right when tying into a roof and/or foundation. The only sure way to know if systems will work as intended is to specify a single source manufacturer. Single source manufacturers spend millions of dollars researching how systems interact with other products like sealants, masonry anchors, and roofing materials. Plus, you get one warranty for the entire system. That’s a no brainer and the last cliché for the day!