Does moisture get trapped in the roof insulation?
I read the building science insight “Leiningen Versus The Ants Redux” by Joseph W. Lstiburek with great interest. I plan to build a workshop in upstate NY (zone 5+) using a similar approach. This seems very similar to the PERSIST method discussed in Martin Holladay’s article “Getting Insulation Out of Your Walls and Ceilings”.
But the details are tricky, as Joe learned with his barn. In Figure 1, Joe shows fully adhered membrane on top of the under-roof sheathing, on top of the roof insulation, and on top of the over-roof sheathing.
Won’t moisture be trapped between the layers of membrane? Especially in the roof insulation which seems to be completely covered with fully adhered membrane?
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