Insulating the Space Between Main floor and Finished Basement
My house is a split foyer that has a finished basement and one main level. I am remodeling the exterior by taking out the old spray foam that has deteriorated, installing Rockwool and Zip sheathing (the house had no sheathing).
I’m not sure what to do about the space in the picture under the wall and above the brick. This space is below the subfloor of the main floor and above the ceiling drywall of the basement. It also cantilever’s out on the front of the house. I didn’t put rockwool there and have already closed it up with the zip board.
What are the implications of leaving this 17″ gap uninsulated and would it be of any benefit to add R5 CI to this space (and consequently the rest of the main floor)? CZ is 4a
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Looks like your pic didn't come through, which makes it difficult to know what you're asking about here...
Bill
Thanks, I realized that after I posted it. I am trying to get it to upload but am having an issue.
Sometimes shrinking the file size will help, or using a different image file format. Other times, you're at the mercy of the forum and it just doesn't want to work. There have been intermittent problems reported with image uploads on here periodically in the past.
Now that I wrote that, I see that your pic came through! Yay!
Bill
I did finally thank you. It was too large it seems, even though it was under 3mb. Had to get it under 2mb.
I wouldn't want to leave that open space uninsulated. It looks similar to a "rim joist like" area. What will be the exterior siding over that area?
Bill
Over that area (as well as the rest of the main level of the house) will be zip board and vinyl siding. Or 1" of R5 CI if I decided to go that route. Stuffing rockwool batt in there didn't initially seem like a good idea given the very large proportion of thermal bridging that would occur in this area due to all the framing.
How would you insulate it? CI or rip off the Zip that I have installed and use the Rockwool? I just seemed to me like the thermal bridging would be so large in that area that the Rockwool wouldn't provide much insulation.
I wonder if it would be possible to forgo the zip altogether in this area and use rigid foam only since it's not part of the wall. I'm not sure what the code would be on that but I believe the wall being covered with sheathing is what I need for bracing. Does this area need to have wood structural sheathing? If I could forgo the Zip and only use foam in this area I could get 1/2" if I don't CI the whole house and 1 1/2" of foam if I do.