Rigid foam insulation advice
I need to replace some siding on my house so I was thinking this would be a good opportunity to add some insulation. I have done quite a bit of research and it seems adding some rigid foam would be a good way. I thought about just having some dense pack cellulose blown in to my walls but that doesn’t appear to be worth it since there is already fiberglass in the 3.5” bays.
I am thinking of adding 1” of rigid foam under LP Smartside. I would love to add more insulation but the roof overhang doesn’t extend far enough to allow this. I thought about extending the overhang but I think that is more than I can bite off right now. I am planning on doing most of the labor myself and I have limited time. I am in climate zone 5 so based on my research on this site 1″ meets the minimum thickness.
Here are the steps I’m planning to take:
Add 1″ foam over the existing OSB sheathing.
Add a WRB over the foam. I have read on here that the foam can be used as the WRB but being a novice I don’t want to screw something that important up.
Add 7/16” thick plywood or OSB vertical furring strips (for air movement).
Attaching new windows over foam to studs with long screws (with proper flashing into WRB).
Nailing the siding through the furring strips and foam then into the studs.
Now for the questions:
1. Does this sound like a good plan?
2. Is all this worth it for 1″ of foam?
3. If this plan is good what method would everyone recommend for fastening the siding to the studs? I’d love to use a nail gun but not sure if that’s a good idea or not. I would need at least 3″ nails (any recommendations?).
4. How important are the furring strips? I was thinking it would be a little easier not to use them but the air gap seems to be worth the added trouble.
5. Would it also be good to add dense pack cellulose to the stud bays while I have easy access to them? Or, maybe just add the dense pack only and skip the foam?
Thanks in advance for the help!
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