Detached garage with attic truss – insulation plan feedback
My plan is to insulation the entire envelope by building 1″ air gap channels in each bay (19.25″ on center) and sealing them with construction sealant and then using pink or rock wool on top of that.
32″ of the garage is attic truss (with a 2′ raised heel) and the rest scissor – see attached photos.
I had the trusses scabbed for more depth in the room truss portion, so that is 11″ deep.
I have questions on what to use for the baffles – XPS or Polyisio (thinking either .5″ Polyisio or 1″ XPS from Lowes – both around 12.50 a sheet). What should I use and I assume the any foil side toward the roof sheathing?
The entire first floor will be drywalled and painted. Since the plan is the “shell” of the building, I will not have insulation between floors.
So the next question is about the room above. I was not planning on drywalling the space initially since it is for storage, but it got me thinking about the effect of moisture through the pink to the baffle since there won’t be any barrier (drywall, etc.) in that upstairs room. Would I be ok? even if I HVAC the downstairs because it is drywalled? I do have a pulldown staircase to access the upstairs from the inside, in addition to an actual door on the left gable end you can see in the pics (outdoor staircase is not built yet).
Any thoughts to my plan?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part