Insulating porch ceiling
I have an enclosed porch on the front of my house with a shed roof (tar roof) that attaches onto my house at about the second story. I live in the mid-Atlantic area where we have both a heating and cooling (A/C) season. I have run heat/ac ducting out to the space. There was no insulation in the ceiling..just exposed ceiling rafters. I'm trying to make the room a 3-season room (that is to say more efficient). I've insulated the floor w/ fiberglass roll. I've also fixed fiberglass roll between the ceiling rafters but I never finished the ceiling..waiting to see what kind of moisture problems I may have. Well of course, the fiberglass insulation has gotten damp and wet on the exposed side to the roof. My question is...How should I insulate this space? I can put in soffit vents..but cannot put in any type of ridge vent because the shed roof butts up to the house? I was going to remove the fiberglass, put in soffit vents, then put a layer of rigid foam insulation on the rafters...and then my finished ceiling (maintaining an airspace between the ceiling/insulation and the roof). I figured a little movement of air in there is better than none at all. Should I install a vapor barrier before placing the rigid foam? Thanks for any suggestions.