How to fix shoddy garage addition?
This past summer I bought a house in SE Michigan (Zone 5a) that was built in 1978; we had an energy audit done and the auditor alerted me to a host of issues included that when they built out into the garage to expand the kitchen & laundry room they left the top of the walls and ceiling open to the unheated garage.
My question is what is the best way to go about fixing this issue from a cost standpoint. I’m concerned if I just seal the top off the wall with XPS & Great Stuff that condensation will collect since there will be colder air inside the wall from the uninstalled garage.
A similar issue with the ceiling, they just piled fiberglass on top of it, but there is no air sealing at all as shown in the pictures.
Thanks in advance!
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Patrick,
Your garage has cold air. Your house has warm air. Between your house and your garage, you need an air barrier and an insulation layer. This air barrier should be adjacent to (touching) the insulation.
I don't know which walls you are referring to -- the ones that have "colder air inside the walls." But it's OK to use rigid foam (sealed with canned spray foam) as your air barrier and insulation layer. The rigid foam, properly sealed, won't encourage any condensation, as long as the R-value of your insulation layer meets minimum code requirements.