inspectorD

The issue with ventilation will not get better with soffit vents only, in fact it gets worse.You let in miosture that cannot get out. If you cannot get any top venting in, just go with the foam board insulation in the porch. I know its a little more expensive but it will hold up longer.Spray foam around any gaps and make sure you hold it off the underside of the decking/roof material (plywood)at least 3/4 inch.
Try to stay away from plastic vapor barriers , they are nothing but trouble.Use the kraft faced paper as I said before.Staple it to the face of the studs,not the sides.
Update any electrical now.
What are you doing for heat? Hope it's enough with all those windows.

__________________
Just My
Made in the

passmaster16

Well, electrical isn't a problem. There are plenty of outlets already. I wouldn't mind eliminating windows and such, but that would be outside the scope and budget of this project. There is no ductwork in the room right now but I am going to have it put in when I get my furnance replaced. My wife's uncle is a heating and cooling contractor and he didn't seem to think it would be much of a problem with using the room all year if the room is insulated and ductwork is in place. The room is literally above the area of where the furnance is. And in terms of cooling, hopefully the ceiling fan will help with circulation.

inspectorD - Ventilation would be tougher in my case because the roof is simply a standard "porch" roof, no ridge to speak of therefore no ridgevent. I'm sure that I could use some other passive ventilation or some type of fan but I'm not sure that it would do a whole lot for such a small area. When you said about using foam board, are you talking about putting this in the ceiling? Does this mean I shouldn't put the R-30 kraft-faced fiberglass in the rafters? Where should this foam board be attached to? And are the vent baffles still necessary just to maintain space between the insulation and roof?

Thanks.

inspectorD

No vent baffles are needed. You can create a space with some 3/4 inch by 3/4 inch material to hold it down from the underside of the plywood. Just install the rigid foam in the bays and foam any gaps.When they are close to being "flush" with the botom of the rafter you can add a 1 inch thick piece to span the bottoms of the rafters the entire way. This creates what is called a thermal break so nothing goes through the roof . In simple terms this creates a foam ceiling and you don't end up with condensation issues like you will with fiberglass.

Doesn't itch as much either....

__________________
Just My
Made in the