My garage is a pool building type with pressed wood walls and exterior siding. I want to put sheathing on the walls for some insulation. The studs that the exterior wall is attached to are 1.5" x 4" being attached flat and run the length of the garage and are attached to the pools. Should I install the sheathing between the studs letting the studs exposed? Or should I attach the sheathing to the studs letting the air space between the sheathing and the exterior wall?
I can't quite picture what you're describing, but covering studs is always better than placing insulation in between when doing so is practical. Studs do not provide good insulation and turn into a heat sink. The dead air space left also provides a bit more insulation. Even better would be to insulate that space, then put more insulating sheathing over that and the studs.