Insulation question for new shed workshop

Colette,

If you are going to want to insulate and control moisture here, you best approach is to move the insulation plane to the roof deck and create some above deck roof ventilation.

It requires a bit more building savvy approach, but it absolutely can be done with some additional framing and rigid insulation. Insulating with just a fibrous insulation without some sort of definitive air barrier is a recipe for condensation and other issues.