I am looking for a wall assembly for an addition / remodel and keep coming back to the Bonfiglioli wall assembly as a good choice.
The only thing I don’t understand is the wall depth for insulation. With 2×6 wall framing, foam strips and 1×3 furing strips that gives you 7.25” of depth. In the article it references R-30 with fiberglass insulation but as far as I am aware there isn’t R-30 available in that depth.
I know mineral wool can fit that cavity but the article specifies using fiberglass as the reason it is a lower cost per sq. ft.
Am I missing something? Anyone have any insight into this?
Replies
Here’s some discussion on what you ask. Green Building Adviser is mentioned, so there might be further info there as well.
https://www.energyvanguard.com/blog/compressed-fiberglass-insulation-really-so-bad/
Calvin, thank you for the link. I read through the discussion on that page and I have reviewed the charts for fiberglass insulation when compressed before. That's what I don't understand though. The Bonfiglioli article describes it as a R-30 wall with fiberglass batts but there isn't a way to get that much into a 7.25" depth.
The closest options I've found is R-30 Cathedral ceiling batts that are 8.25" depth but when compressed gives you R-27. There is also R-38 Cathedral ceiling batts that are 10.25" depth but when compressed in the 7.25" cavity will only give you R-29. I guess that is close enough to call R-30 but then the cost doesn't make sense.
I've looked through Green Building Advisor as well but haven't found any information on it either. I feel like there must be some detail that I've overlooked but can't figure it out.
P.S. Looks like I'm just down the road from you!
Maumee, Ohio
Back in the woods above the flood plain.
Luckily, most people are unaware we live back here.
Guess a long lonely driveway (spooky) is enough.
And where would you be?
(Edit: I see now, Lima.)
Back to bizness. Search here for Mooney Wall. A long ago member dreamt it up. And a good builder friend from Rhode Island has done it many times. Similar idea but with blown cells.
You are right about the 2x6 wall assembly creating a 7.25" depth, which doesn't typically match R-30 fiberglass insulation. The article may prefer fiberglass due to its lower cost. Remember, insulation performance depends on more than just R-value; factors like installation and climate matter. If you are concerned about R-value, consult a roof repair local expert for tailored advice..