|
I figured this would be a little too detailed for the fix it fast thread, but I can close and repost there if this is not thread-worthy. I own a 1920s-era house and have all the drafts and cold spots that come with the territory. There is a basement under most of the house, though there is a bump-out off the back of the house for part of the kitchen/breakfast nook. There is an unventilated, unconditioned crawlspace under the bumpout, roughly 8' x 16' with about 5' of headspace. The bumpout over the crawlspace is usually at least 5 degrees colder than the rest of the kitchen, which is over the basement. Thus my desire to insulate the crawlspace. Internet advice on crawlspace insulation varies and doesn't seem to cover cases where an unconditioned crawlspace is off a conditioned basement. The crawlspace is separated from the basement by a cinder block wall. My plan was to put up a vapor barrier on the inside of the 3 exterior walls of the crawlspace, put in R8 EPS rigid insulation (Insulfoam), tape the ground vapor barrier to the wall vapor barriers, and seal all joints with tape. I would also use rigid foam over the rim joist/sill plate area. A few questions: -There seems to be varying opinions on vapor barriers and crawlspaces. Is my plan appropriate for an unventilated, unconditioned crawlspace? There is no insulation or waterproofing on the outside of the foundation. The crawlspace does appear to stay dry. -Should the interior crawlspace wall (shared with the basement) also be insulated the same way as the other 3 exterior walls? -Should I add ventilation or not? -Will this actually help keep the breakfast nook warmer? I realize this may not make complete sense if you're trying to visualize so I can make a diagram/take pictures if that helps.
|
#
?
Oct 17, 2015 17:49
|
|
|
|
| # ? May 14, 2024 22:36 |
|
|
Helvetica Sucks posted:-Should the interior crawlspace wall (shared with the basement) also be insulated the same way as the other 3 exterior walls? Any foundation wall should be done in the same way. To do it properly, generally, you'll want everything looking uniform and the same. No, if you're putting a vapor barrier on the walls and floor you don't want ventilation as that'd make it hotter/cooler. Yes, it will be warmer.
|
|
#
?
Oct 17, 2015 23:51
|
|
|
2 inches of EPS is already a pretty good vapor retarder (1-3 perms), you don't need to use plastic in addition to that. Aside from that, your plan sounds fine to me. You don't really want a crawlspace that is both unconditioned and unventilated. I would suggest making it a conditioned (or semi-conditioned) crawlspace by adding some vents into the conditioned basement. If you do so, there's no point to insulating that shared wall. It definitely should help keep the bumpout warmer, but it still could be noticeably colder than other areas thanks to 3 exterior walls.
|
|
#
?
Oct 18, 2015 04:24
|
|
