Insulation upgrade on century old home
Theres a government incentive that will do some insulating but they have specific insulation types they will do. I recently got rid of my knob and tube in the attic, and they found all the walls are balloon framed and have the tops open in the attic (i only knew about some of them, where the addition was added).
I have part basement, part dirt crawlspace, in the crawlspace they want to spray foam the headers (which are open and have wall filled cellulose coming out of them) and fiberglass the brick foundation, i am skeptical about fiberglass blankets on the foundation since i don’t know how safe it is to insulate the brick. I am hoping the foam portion helps with air sealing. Thoughts?
The attic is part conventional, part almost flat, starts at about 2ft of height and goes down to nothing. In the conventional attic the walls are balloon framed and open .So how do you properly insulate/air seal the top of the walls that are open from basement to attic in the conventional attic and are also balloon framed and open from basement to attic between the conventional and flat part of the attic?
Their suggestion is cellulose on the conventional attic and filling the entire space with cellulose with no air space in the almost flat part. Is this wise?
No suggestions from them on the open tops of the walls, any suggestions on this?
Thanks
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Before you do anything you definitely want to seal those cavities in the attic. What I have done is cut pieces of 2x4, tacked them into place and spray foamed on top to seal it up. Ballon framed houses have a lot of ugly leaks like this, you want to plug most of them before any insulation. Much harder to do once the fluffy is in the attic.
You are correct about not wanting the fiberglass blanket insulation. Figure 6 here is pretty much bullet proof.
https://buildingscience.com/documents/building-science-insights-newsletters/bsi-110-keeping-water-out-basements
If you don't have water issues, you can skip the interior drainage but you still want a layer of spray foam. You can then install regular batts over that if you want more R value.
I would be concerned the brick foundation will crack over time, then its bye bye house.
The balloon framing is tricky to remedy, there is old kraft faced fiberglass up there now as well as decades of crud accumulation. The insulation company proposes to just put cellulose over everything and do no air sealing.