When to Use a Fully-Adhered Air Barrier Membrane
Finalizing my renovation plans and getting ready to start ordering stuff — Adding continuous exterior insulation (polyiso) to roof and walls of a house with 1x board sheathing. I’ve been planning to use Solitex Adhero (a fully adhered membrane) applied under the insulation, based on the assumption that something fully adhered will perform better on old board sheathing that has more holes and gaps than new OSB / plywood — and I won’t need to tape over a bunch of staples. Plus, I can use the same product for walls and roof.
But, my specialty is second-guessing myself — Is my intuition on appropriate applications of a fully-adhered membrane (vs. stapling up Mento or something) correct here?
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Replies
Jonny_H,
I don't have personal experience installing Solitex Adhero, however, depending on how "funky" your situation is underneath, full adhered barriers can be tricky to install and keep clean and tidy, especially if you're having to navigate other penetrations, protrusions, etc.
That said, yes, that is a good reason to use full adhered. It is difficult to detail non-adhered WRBs (like Mento) as an air barrier and will be made more difficult. Not impossible, just a little more finicky to maintain continuity.
Another relevant question I suppose would be your siding choice and how it will be fastened. Will you be fastening into studs or into the board sheathing. Another major advantage of fully-adhered would be the fastener self-sealing ability.
Seems to me you're on the right track.
VP100 very popular for this application in my neck of the woods.
As someone who did Mento on board sheathing (new, site milled), I really wish we had considered fully adhered. It would have made those walls much more air tight!
Well, that's 3 votes nominally for fully adhered and none for anything else -- so I'll stop second guessing myself and go ahead and order materials! Thanks!
One benefit of most peel and stick membranes is that they can be installed in the vertical direction without any extra overlap. This makes installing on a ladder much easier as you can tack it on the top and peel the backing and adhere as you go down the ladder.