Staggared stud walls & 14″ TJI roof… How should I proceed with Insulating? Zone 5
MikefromtheMountainsofUtah
| Posted in General Questions on
I assumed I would have 2-3″ of closed cell foam sprayed, but wonder if that’s the best way to proceed now. Polyiso 2nds seem very inexpensive so I primarily wonder if I could save thousands by air sealing with cans of foam and then cut, place, and foam around 3-4″ polyiso sheets before batts go in.
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Replies
Mike,
What R-value are you aiming for in the roof and walls?
The code minimum is 49 for the ceiling and 20 for the walls. However there are a couple sources locally that sell insulation 2nds for cheap enough that I just figure I'll end up filling all the cavities.
We call what you're proposing "cut'n'cobble", and while it can work, it's a LOT of labor to install. If you can contribute free labor to your project, it's certainly doable, but I wouldn't ask any professional crews to insulate this way.
Have you considered dense pack cellulose? You'd still need to air seal the old fashioned way, but that's likely to be cheaper than a spray foam job. You could put the polyiso on the exterior to gain some additional performance for your wall assembly.
Bill
You're right... I'm probably underestimating the hassle of being on my scissor lift with foam board. I'll just have them do the closed cell for a couple inches again. Thanks