Our house is in the Preston St. area of Ottawa (ON) and forms the back part of the second floor. I opened the walls at different locations and found that they were constructed as follows. Stucco over 3"x12" wood timber, brown paper, slat, lathe and painted plaster walls. A paint chip reveals one layer and was probably painted shortly prior to our purchase in 2000. Does this change your answer as to why these walls seemed to sweat after I removed the temporarily placed R10 rigid extruded poly panels. Can I still glue the panels to the wall and drywall over top doing something else to remedy the situation? The ductwork is too close to the wall to consider 2x4 framing.
Answer:
No it does not because a well applied coat of paint can serve as at least a partial vapour barrier and that could well be your problem. I would be concerned though if there were any air gaps in that wall because condensation would be almost sure to form.
