Freezing home with wonky basement/crawl space config
We have a home built in 1925 in CT (zone 5a): 1/4 of the 1st floor has a stone walled basement beneath that is partially bedrock/drilled into for drainage so we can not close it up; at least 1/2 of the 1st floor has a very shallow dirt floor crawl space with a/c ductwork and oil line that leads to our garage in it; and the remaining section is our kitchen which we believe is sitting directly on rock or slab or some rock solid surface.
The crawlspace opens into the basement so we can see inside a bit bt it’s so shallow our home inspector could only get a camera through half of it.
We havent had a humidity moisture problem yet (we’ve only lived here for 1 yr), but it is very, very cold.
Today it was 26 degrees outside and we couldn’t get the first floor above 66 degrees. The windows and doors and relatively new, the attic has fairly recent and good insulation and the 2nd floor seems normal in regards to energy efficiency. We even had the state come out to do an audit and fix anything we have missed in regards to energy efficiency.
What are our options to better insulate beneath the house considering how tight of a space it is, what is in there and how it opens to a more open space whose walls can not be covered (because of the drainage ‘solution’)?
Thanks in advance!
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Replies
What kind of insulation do you have now? What kind of heating system?
Hydro air powered by Oil & there isn't any current insulation in the basement
What kind of insulation in the crawlspace?
If the crawlspace is uninsulated you need to insulate it. You need to insulate the basement too. You have to decide where the boundaries of your building envelope are -- where you heat and cool.
If your crawl space is inaccessible from below you're options are either to gain access from above or from below. I guess a guy with a wand might be able to lie on his back and spray closed cell foam, although it would be messy and uncomfortable and he won't be able to do a good job where he can't see. If you can figure out a way to close off the joist bays from below you could blow in cellulose or fiberglass from above through a 4" hole in the floor in each joist bay. If you have cabinets you could remove the cabinets, put holes in the floor, blow in the insulation and put the cabinets back. If you have wood flooring that goes perpendicular to the joists, which is normal, you could take up a couple pieces of flooring at one end of the wall, drill holes in the subfloor for the insulation, and put the boards back. You may also be able to blow from below depending on your joist layout.
>"...1/4 of the 1st floor has a stone walled basement beneath that is partially bedrock/drilled into for drainage so we can not close it up..."
I don't have a clear picture of why the foundation walls can't be sealed and insulated.
>"The crawlspace opens into the basement so we can see inside a bit bt it’s so shallow our home inspector could only get a camera through half of it. "
It may still be possible to put in a ground vapor barrier and insulate that part of the foundation from the exterior (TBD.) At the VERY least is should be possible to air-seal the band joists on the crawlspace, (not that it's necessarily going to be easy), from the exterior, if not the interior.
Even if the attic is reasonably insulated, it may not necessarily be sufficiently air sealed, particularly at the flue and plumbing stack chases, or even the partition walls. A symptom of an air-leaky attic floor plane is a cold first floor, since the stack effect draws the warmer air out the top of the house, sucking cold air into the basement & first floor by whatever paths it can find. A water-leaky foundation doesn't mean you simply can't air-seal the basement, but the particulars will dictate how. The two most important areas for controlling air infiltration is at the attic floor plane and the basement/foundation.
The attic is probably the easiest to access, so that's the best place to start. But flue & plumbing stacks can usually be air sealed at the basement ceiling, which will at least slow down that 24/365 infiltration path. Those basement-to-attic chases can & should be sealed at both the attic and basement.