Drainage channel under continuous exterior insulation?
jameshowison
| Posted in General Questions on
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Expert Member
Michael Maines | | #1I haven't read the guide yet but I would guess that it has something to do with this: https://buildingscience.com/documents/insights/bsi-038-mind-the-gap-eh
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jameshowison | | #2I mean, maybe, there is a discussion of "crinkly" housewrap under exterior continuous insulation around here: https://buildingscience.com/documents/insights/bsi-038-mind-the-gap-eh#P09
But that seems to be when you have vapor impermeable insulation both sides (or at least outside).
I'll keep reading the document and see if I can figure it out :)
I was checking out TimberHP’s new builders guide: https://www.timberhp.com/guide-for-builders (developed in collab with Joe Lstiburek).
Curious to me that they include a 1/6″ inch “Drainage Gap” between the continuous exterior insulation and the roof decking. Odd to see that “in the middle” of the insulation stack (there is air permeable insulation beneath).
Anyone seen this before? How would that be implemented? Could there be such a thing as an air-tight drainage gap (perhaps vapor open, but air-sealed at the bottom?)
I was checking out TimberHP’s new builders guide: https://www.timberhp.com/guide-for-builders (developed in collab with Joe Lstiburek).
Attached pic is on Page 56 of the PDF.