Cold floor over crawlspace
Problem: My house is uncomfortably cold during the winter, especially the floors. Running the heat leads to excessive dryness.
House details:
Located in Charlotte, NC (Zone 3)
Built in the 1970’s, on a sloping lot.
Sits on a crawlspace that varies from 3’ to 8’ high.
有大量的外壳窗户
Has a cathedral ceiling in the living room, which is by far the coldest in the winter.
墙壁用玻璃纤维板隔离，并用刨花板和垂直雪松壁板护套。没有房屋包。
Floor is insulated with fiberglass batts that aren’t in great shape
We’ve already laid down plastic in the crawlspace, plugged the vents, and added a dehumidifier. This was done to prevent mold.
I’m open to other suggestions, but I think the most economical solution would be to deal with the cold floor. The crawspace gets cold due to the tall uninsulated walls. I think I have two options for fixing this:
Option 1: Spray foam the crawlspace walls. Rigid foam probably won’t work, because the walls aren’t flat (CMU pilasters with brick infill). Unfortunately the high side of the crawlspace has some drainage issues, and causing water to travel beneath the poly which covers the dirt floor. I’d probably have to rip out some mature bushes and install a french drain to fix this. Also, spray foaming the band sill is risky, because my deck ledger is not properly flashed.
Option 2: Attach 1” polyiso to the bottom of the floor joists. The advantage is that i could probably do the work myself. One disadvantage is that there will still be heat loss through the ducts. Also, it could get tedious taping all the joints, notching around footings, and dealing with Romex and piping that is attached to the floor joists.
Any comments on my best option are greatly appreciated.
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Replies
J.,
Put these three things together:
1.“冬季我的房子很冷。”
2. "Running the heat leads to excessive dryness."
3. "The room with a cathedral ceiling is by far the coldest in the winter."
...and the evidence screams one conclusion: "This house has air leaks."
泄漏不仅在您的地板系统中。它们也在您的屋顶组件中。
这是一篇文章的链接，该文章解释了您需要做的事情：“吹风机定向空气密封。”
嗨，J-
Your options describe an unvented (insulate/air seal exterior walls) and vented configuration (insulate/air seal the first floor assembly, even though in your case since you say you are running a dehumidifier in the crawl, you--hopefully--are not currently venting.
根据我的经验，比爬网空间外墙更难在一楼的组件上获得连续的绝缘和空气密封。推荐选项1。
But regardless of what approach you take, the rule is manage bulk water first, before you air seal.
Peter
Martin,
I'll see if anyone offers that service in my area. You are right that I probably have leaks, regardless of how poorly my home is insulated. Things were a lot worse before I sealed off my whole-house fan opening, but i'm sure there are other less obvious leaks.
Peter,
您可能是正确的，在托梁下方获得具有刚性泡沫的良好密封将很困难。切割每个管道，HVAC和电渗透以及地基墩将是一场噩梦。我只需要咬着子弹，并在我家的前面安装宣传或法国排水口即可处理水。对于我的未弹药甲板分类帐，我可以填补窗台，而不是喷雾泡沫，以便它仍然可以向内部干燥。
Thanks again!