I am using the top floor of a detached, two-car garage for a woodworking shop. I would like to insulate the rafters, since it gets very warm in summer and cold in winter up there. Should I use insulation with a vapor barrier built in, or will this cause condensation between the insulation and the sheathing? The bottom floor is heated with a wood burning stove, and the top floor is unheated. I really don't know if a vapor barrier is a good idea in the rafters of a roof. Thanks in advance,
Mark

You need to have an air space between the insulation and the roof sheathing or you will create many problems. Once that is done you may even want to put up an inexpensive ceiling to help matters out.

I understand that I should keep a space between the insulation and the sheathing to protect the sheathing from rotting, but should I add a vapor barrier between the insulation and the knotty pine boards I intend to cover the rafters with? Thank you.

I understand that I should keep a space between the insulation and the sheathing to protect the sheathing from rotting, but should I add a vapor barrier between the insulation and the knotty pine boards I intend to cover the rafters with? My email is dusty@exis.net. Thank you.

I understand that I should keep a space between the insulation and the sheathing to protect the sheathing from rotting, but should I add a vapor barrier between the insulation and the knotty pine boards I intend to cover the rafters with? Thank you.

Sorry I forgot to actually answer your question. My advice to you would be no for the following reason. You are not going to be heating this room constantly and the temperature will change dramatically once your wood burner gets heated. This radical change is great for condensation. I cannot say for sure that it will condensate, but, the conditions will be ideal. I hope I did a better job of answering your question this time!!!!!

I also received an email that mentioned installing a ridge vent and channels that keep the insulation from touching the sheathing. The air flow should eliminate the chance of condensation. The ridge vent is a little beyond my means right now, but I'll keep my eyes open for those channels before I start laying insulation. Thanks for the great suggestions!

Regarding the channels that you're talking about. I just purchased some locally at Lowe's. About $7.00 for a package of 20, made of styrofoam. Easy to install with a staple gun.