Basement – existing vapor barrier over concrete
Hey all:
I’m about to start finishing my basement (MA, Climate Zone 5) and have a wall assembly conundrum. We installed an interior perimeter drain and sump pumps a few years back. As part of that system, a vapor barrier was installed over the concrete walls, fastened to the wall and sealed at its perimeters. It ties into a plastic flange at the wall-slab edge joint. The aim is to encapsulate the concrete wall and direct any moisture on walls down into the perimeter drain below the slab. (Our walls have never had any moisture issues, but the vapor barrier was included as part of the system.)
根据我在这里和其他地方阅读的内容，我一直认为我需要在安装之前删除此内容。在地下室中针对Poly的基本原理很明确（尽管安装在warm在螺柱的内部面部，防止干燥到内部。）
这是目前在我的基础墙上的产品：https://www.grateproducts.com/moisture-control/thermal-shield-vapor-barrier.html. It’s a two-layer plastic sheet (0.014 perm) with about 1/8″ of insulative material inside, it may have some nominal R-value and could have slightly less potential as a condensing surface than the bare concrete.
Thanks all!
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Replies
嗨，迈克，
I'm curious why you had the perimeter drain installed if the basement hasn't had any water issues. With a perimeter drain, the idea is that any water that enters through the basement wall can make its way down the wall to the drain and sump and be pumped out of the house. So, if you take the existing vapor barrier down, you'll need a dimple mat or similar product to create that drainage plane before installing the new rigid foam. Do an excellent job air sealing the new rigid foam before you build your stud walls. Have you read this:How to Insulate a Basement Wall?
感谢您的回复Brian（顺便说一句，您在FHB播客上的工作的忠实拥护者。）外围排水管的起源是由于在平板边缘出现了水，并且自从安装排水管以来一直干燥。值得庆幸的是，墙壁一直干燥。
Here's where I landed with my builder: keeping the vapor barrier over the foundation wall tied into the drain, installing the rigid foam over that. Filling any voids with spray foam, taping seams before studs and sheetrock.
Thanks again for the input!
Mike