Addressing gap between fieldstone foundation and rim beam (built 1900)
I discovered several gaps between my fieldstone foundation and ridge beam (home built ~1900 in MA).
My inclination is to pack with non-shrink grout for more beam support and stopping the air, but I don’t know
1) if temps are appropriate right now, and
2) if i’m going to cause another issue due to direct contact with the beam.
Also, many of the gaps would be way too small for me to pack in… could I use something like a R Guard joint and seam filler from Prosoco or Zip Liquid Flash?
MassSave did air sealing and insulation last year. I found these gaps while investigating why my basement was still so cold this year.
I’m open to a two step process that includes a current stop gap for the air leakage (stuffing with mineral wool??), and then addressing the problem more permanently when it’s warmer out.
Thanks for your input!
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Replies
You need a few days of relatively warm temperatures for mortar or spray foam to cure. I'd pack it with mineral wool for now. It will slow airflow but won't prevent it. Once it's warm outside, remove the mineral wool and pack the gap with mortar. Once that's cured, seal one or both faces with a fluid-applied membrane such as R-guard.
Thank you!!
I find canned foam works best above about 50F or so. If it's too cold, the canned foam doesn't expand very well and gets bubbly/crumbly.
I'd follow Michael's advice for now, then, when it's warmer, you could use mortar for support, and you can inject canned foam into the gaps to air seal the irregular spaces. You'll probably need an extension tube for the canned foam to let you get into those gaps -- if you can't hold the can in the right position, you'll waste a lot of foam when the propellant blows out without doing much actual foaming. It can be awkward to use canned foam in these kinds of confined spaces.
Bill
I had a similar issue with my 1970s cape. The builder had the entire mudsill raised slights off the foundation with shims. I spray foamed the entire permiter gap and used about 6 cans of foam. The basement is much tighter now.