I live in a solid brick 1920's home in Montreal Canada. I need to insulate, especially in one part of the house as it gets VERY cold in the winter. The plaster walls are typically very cold to the touch from November to March.
I have removed all plaster on the inside of the wall and my plan is to build a cavity with 2x4s for the fiberglass batt insulation that i plan on using.
My questions are:
1-do I build the new 2x4 wall up against the brick or do I leave a small space of about an inch for air circulation?
2- in terms of vapor and air barriers, my plan is to use a high quality vapor barrier on the inside between the 2x4 structure and the new drywall...and for n air barrier I plan to staple tar paper on the structure facing the brick wall. Is that sufficient? is there a better choice for air barriers?
thank you in advance for your help