I have a 1950's brick home in Virginia with true plaster interior walls and
it's time to repaint a stairway wall. The paint is in pretty bad shape. It
flakes off easily with the blade of a chisel, with all layers of paint right
down to the plaster skim coat coming up. It's as though the paint never
really bonded to the original plaster. This failure to bond seems to have
occured only on the exterior walls so I wonder if the lack of housewrap and
thus colder surfaces might explain the peeling. The task before me is to
either scrape all the old paint off or perhaps to paper the wall. But I'm
also wondering about adding a layer of 3/8" sheetock directly to the
plaster. The plaster wall is quite cold to the touch and I wonder if I'd
gain some insulation, especially if I added a layer of some sort of very
thin insulation before adding the sheetrock. Back when our home was built,
contractors just put lath directly on the brick or block without any
additional insulation. I know I'd have to remove molding around windows and
at the baseboard, but that's not a huge project. I'm not sure how I'd handle
the joint where ceiling meets wall because the ceiling goes off at a 45
degree angle, not the normal 90 degrees.

Would I gain much feeling of warmth with the additional sheetrock? What
product would be best for the thin foam insulation? Any new products better
than plain sheetrock which I know doesn't have much of an R factor?

Thanks.