Insulation type for garage attic with Ridge Vent and Soffits
I have an attached 2 car garage that has it’s own roof in the Dallas, TX area. The garage is finished with sheet rocked/dry walled walls and ceiling. The attic space above does not have any insulation (not on the floor or the rafters). The roof is composite shingles with a ridge vent and a few soffits on each side. The attic space shares a portion of the home’s exterior wall of a bathroom and a bedroom (this wall currently has fiberglass insulation with some areas not covered well).
We do have exposed PVC drain pipes (toilet and tub) from the bathroom that come into the attic space.
There are no plans to convert this attic space to a livable space.
Should I at least get the shared wall spray foamed?
What would be the best insulation option for the rest of the attic space?
Thank you for your suggestions,