Need help upgrading my homes insulation!
(Sorry for the long read)
Hello! We are currently renovating our home that was built in 1996 and we are located in climate zone 5 (western new york). It has come time to tackle insulation. The house is always a little chilly and we are aware that there was a rodent problem in the past that has since been delt with by us. Previous owners didnt take the best care of things….
The old insulation setup was yellow fiberglass batts with a poly/plastic vapor barrier then drywall on top. I was never a fan of this approach as there is always a chance the poly/plastic vapor barrier will get punctured by nails (pictures, shelf’s, etc). So I’m trying to find a good way to upgrade the homes insulation while also preventing condensation in the stud bays. Now that the walls are opened up, this is my chance to better insulate this home. Exterior insulation isn’t an option. We also didn’t plan on using spray foam.
I have been doing research for 2+ months now and still haven’t gotten a solid answer regarding what’s best for my climate zone. I was debating installing 2” of XPS ridged foam board in each stud bay, then installing unfaced rockwool batts behind that then drywalling. In my climate zone, 2” of closed cell foam quality’s as a thermal break so I figured I don’t need a plastic vapor sheet before the drywall. I plan to seal all the joints around the ridged foam board before I install the batts to prevent warm air from coming in contact with cold air. I understand there will still be some thermal bridging with the studs, but isn’t that how all homes are? There’s no way to add a thermal break for the studs without either exterior insulation or expensive T-Studs.
Useful article: https://buildingscience.com/documents/building-science-insights-newsletters/bsi-116-interior-spray-foam (I was thinking instead of spray foam, I could just use 2” ridged board foam). Same outcome as the image picture below, just not with spray foam.
All I know is that I want better insulation for my house while also preventing condensation from forming inside the stud bay and rotting out my wood and causing mold. I’m open to ideas and suggestions. I really need help here. Thank you.