Do vapor barrier or moisture transfer concerns apply similarly to ceiling and floor assemblies?
Now that i have grasped the concept of Vapor barriers for Walls specifically, (for my Climate zone 4A)… (that rather air sealing is the crucial component to prevent vapor transfer), that i can just use a breatheable vapor barrier one on ONE side… (ie Certainteeds MemBrain btwn my Rock Wool Comfortbatt and Sheetrock) so the walls can still dry to the inside…
Conceptual Question: Q1 So then, how do i approach, the proper way to assemble Floor and ceiling layers? ( other than of course, air sealing the enclosure?)
Q2. Simply to keep the surface of my double layer of Roxul Rock wool ceiling clean from dust and insects, can i gently place a layer of Lowes house wrap ( highly permeable) atop the Rock wool layers, since i have vented gables in the small attic? If not, what other suggestions do you have, and why?
Q3. For the sections of subfloor i had to tear out, which had roofing paper btwn the plywood and base pine planks, what should i replace, the roofing paper, i imagine, with a breatheable semi permeable covering…either the MEMbrain or the Lowes wrap? (It is a crawlspace that i have to clean some mold from Rim joist area, and all dust/spore filled fiberglass insulation has been removed. The Crawl has sealed vents, new 6mil plastic taped to block, and dwhumidifier running. But not FULLY encapsulated.)
Q4: So essentially, do i want to prevent air from crawl entering Living space from below with an impermeable material? Or is better to have it breathable? ( no radon issues last time i checked)
Thx for your advice,
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