Insulation roof/ceiling help.

[horsePOOGAS]

Hello all. Looking for some insight. I have a 15'W x 40L x 7'H on the lowest slopped side. 10'H on the high side. add on to the side of my garage that I've got concrete poured and I'm enclosing. The roof was pre-existing. It's a simple metal roof sitting on top of the wood frame.

I'm putting a ceiling in and I want it insulated. I've looked into spray foam and I know what I can and cannot do with that. What I don't know and why I'm asking is if I went with tradition insulation and made a "Attic" area. I believe I would need some sort of moisture barrier between the metal and insulation..So my question is can I install a barrier in between the rafters and butted up against the metal and it be sufficient enough? I guess the only place there wouldn't be a barrier is where the metal meets the wood rafter.

I live in the southern part of Indiana to have an idea of my climate.

I may be completely off base in my thinking here and I'm hoping to get some good insight or constructive criticism lol

 

[tyme2par4]

The first question would be is the current garage insulated, and does it have a vented attic space? If it does, you will have to maintain that ventilation.
Do you plan on making a flat ceiling and drywalling it? If so, I would just blow in cellulose over the drywall.

 

[horsePOOGAS]

The first question would be is the current garage insulated, and does it have a vented attic space? If it does, you will have to maintain that ventilation.
Do you plan on making a flat ceiling and drywalling it? If so, I would just blow in cellulose over the drywall.

The space I'm enclosing will be insulated. If I went with "attic" space yes it will be vented. The ceiling will not be flat as I planned to follow the roof line as close as possible and I planned on using OSB board for the ceiling.