Best option to insulate 1920 bungalow walls
Hello, been a long time! I recently put in R40 blown in fiberglass in my attic and it has made an amazing improvement and I’m now looking at my walls. My entire house had no insulation and is a craftsman built 1920 Bungalow in Tampa. All wood framing with raised crawlspace. I did air sealing in the attic before insulating. I also recently replaced all windows with double paned impact LOW-E.
My main concern now is my South and East walls that get a heavy dose of Sun. The room on the SE corner is still noticeably hotter. Measures about 3-4*F hotter than the rest of the house by noon. It was much worse before the windows and attic insulation. There is still sun heat entering through the windows, I have measured it, so I plan on installing additional exterior window tint to hopefully combat most of it.
I use this as my office so it’s a big deal, and I have several options:
1) install additional cooling by adding another duct and vent
2) install blown in insulation via holes into the walls, hoping to dense pack it
3) remove the exterior sheathing and install 1-2” of polyiso and new sheathing over it. This is an option because I’d like to replace the exterior asbestos tiles as insurance carriers are now dropping houses with them.
4) spray under the floor with 1-2” of foam. I would probably use open cell to ensure water vapor can still travel. Currently the floor is wood on trusses, a 3.5” air gap, then 3/4 plywood. I could also easily take the plywood up and fill the air gap with blown in or batt insulation.
My current plan is 2 and if that’s not enough also do 1.
Anything I’m missing?
Is 4 going to make much of a difference?
What is the difference in doing 2 and 3, I’ve tried researching this but came up with nothing.
Thanks all 🙏🏼
GBA Detail Library
A collection of one thousand construction details organized by climate and house part