We tested a house today that used Typar as an air barrier. Many builders like the texture of Typar and find it easy to work with as an air barrier, but in our testing today, we found excessive air leakage due to a few problems.

Firstly, it was apparent that the membrane had been damaged, likely by flapping in the wind for a few weeks before it was tied down. The translucent parts were not air tight and defeated the purpose of installing it in the first place.

The second problem, and this is a common issue is that Typar has to be installed label to the exterior and the Tuck Tape only sticks to the labeled surface, not the fuzzy back. Many of these seams were leaking air.

The contractor, having built his first double stud wall assembly, had never been through an air tightness test and was very interested in the process. I suspect his next house will be substantially more air tight.

We suspect the translucent pattern where the printing was worn off on the face of the material was leaking air directly through the membrane at low pressure.  We commonly see  Tuck Tape “adhered” to the fuzzy back-side of the membrane and it never holds fast.