Hi Curtis and anyone else willing to stick their neck out. Since I have somehow managed to find myself grouped among experts I thought I better ask this question before it pops up in my own forum! *g*

I have been hearing of situations where twisting and drying of the timber frame has
caused panel movement, resulting in air infiltration at panel joints. I understand
that a silicon caulk which is less rigid than foam, has begun to be spec'd by manufacturers. Is this to compensate for the movement and is it permanent? My concern is
migration of moisture laden air through the panel seams will result in condensation
in the panel, resulting ultimately in rot and delamination of OSB and panel.

Is it possible that a membrane or gasket such as bituthane be applied to the joints
to further seal these joints? If so it would seem more effective to apply it over the seams on the exterior of the panel, since a twisting timber could conceivably pull the gasket away from the seam?

It seems that such a solution will also reduce moisture under the roofing, reinforcing the arguments against cold roof requirements.

Thanks

Hi Paul:
Well I do not know if I should stick my neck out but.....
As with all building stystems, the time between invention, initiation, and failure is a variable. As systems develop they are constantly being refined. The nature of an enclosure that relies on a seal that must withstand many forces and is yet untested by large spans of time will prove itself one-way or another eventually. I know in my own building career that theories of all systems have evolved to the point where we all realize that what we did ten years ago is at least outdated and perhaps even totally wrong.

I have never installed a gasket as you have suggested, but I have given a ventilated airspace to many structures both on sidewall and roof deck. Paranoia strikes deep. The purpose of this air space was to deal with the eventual failure of my own work and the chemistry involved.

The answer? No one else seems to have any ideas or they are staying away from the topic.

I am sure this thread will continue for years to come.