[Greenbuilding] EIFIS as Air Barrier

Eli Talking elitalking at rockbridge.net
Wed Apr 3 14:58:03 CDT 2013


Hello wise list.

Since the accepted practice for Exterior Insulation Finish System (EIFS) is 
to have a drain dry plain such as stucco building wrap to the interior side 
of the rigid insulation, it strikes me that the foam can not be an affective 
air barrier.  The drain dry capability requires access to exterior air.  The 
stucco wrap itself can be an air barrier if installed perfectly.  However, 
winter air might make this cold, increasing vulnerability to condensation. 
Extra infiltration from imperfection could facilitate drying at a expense of 
heat loss.  Does this increase infiltration to the interior.  It seems to me 
that an affective air barrier that is in full contact with non permeable 
insulation, such as foam should be on the interior side of the drain dry 
plain.  Do any of you have direct experience with this issue such as a 
blower door test.  I have an associate that wants to use EIFS.

One possibility is to have minimal rigid insulation outside the drain dry 
plain to install the finish and the real continuous impermeable thermal 
barrier to the interior side.

Thoughts?

Eli







More information about the Greenbuilding mailing list