Is it necessary to insulate a soffit that houses an A/C duct? The A/C duct has insulation wrapped around it, however I built a metal frame around it and want to cover the frame with sheetrock. Do I need to insulate this soffit or is the insulation aroung the A/C duct enough?

I have a new bathroom that I am building and one wall of the bathroom is adjacent to a closet. Is there special insulation that I should use to prevent moisture from the bathroom to the closet wall, or will the sheetrock be enough?

Lastly, what insulation is recommended for bathroom walls and around the tub area?

Question 1, If the AC duct is in a soffit area(that is the overhanging area at the roof line=soffit)no additional insulation would be needed.

Question 2 and 3,while typical drywall is for the rest of the house, greenboard(or moisture resistant drywall) is for higher moisture areas, like kitchens and baths,this will allow you to think easier verses trying to think about moisture getting to your insulation,normal insulation can be used around the entire bathroom(special circumstances would be pipes exposed to outside walls for example,where pipes would need special attention.)

Hope this helps,

KBC

I hope you are leaving room in the soffit for good venilation. Otherwise KBC's answer sounds good.