Insulating rafters

[Shanley]

I would like to finish my attic for a home office...My house was built in 1890 and does not have any roof or soffit vents (additions have been built on each side of the house so soffits are not continuous)...I want to insulate, should I insulate with fiberglas insulation between the rafters...If so , do I have to do anything to avoid the builtup of condensation at the underside of the roof sheating...We recently had a new roof put on the house, plywood sheathing over the old t&g board sheathing and asphalt shingles...Please advise

[Rich]

Is there any way to get air flowing across the whole attic instead of soffit vents? I'm not sure what you have as far as gable ends and where they are in relation to the new additions. But to insulate you should try and get some airflow between the sheathing and the insulation...
or possibly better yet would be to inset your framing from the rafters (a room within a room) and insulate just the new framing - allowing what air you could get up there (through new gable vents) to handle the condensation. Grumpy may have some other ideas on this.