Converted attic insulation/ventilation
I am re-doing a converted attic to correct poor ventilation. There is currently fiber bat insul in the rafters with no soffett or ridge venting. I am removing old insul and installing baffles then re-insul. My question is, I only have 3.5 inches to work with from the roof to the edge of the framing. Without building out the framing to accommodate 3.5 in bat insul can I use 2 inch rigid insul and still get good R value for Connecticut? What is best R value I can expect. R-10 is the best I've seen. Any help is appreciated.