I have a 1950’s cape style home. As is common with the design, my second floor has a smaller footprint than the first, so there is kind of an “attic” space between the second floor walls and the underside of the roof. Through doors I can gain access to these areas with relative ease.

In this space I can see the back sides of the second floor walls. I can also see the top of the ceiling for the first floor since the first floor is bigger. Lastly, I have limited access to the real attic above the second floor, which is maybe 3’ high at the center. Part of the ceilings of the second floor rooms are angles, and the plasterboard is nailed directly to the underside of the roof beams. These attic spaces get really hot in summer, and cold in winter. We are ion Northeast Pennsylvania, so snow is not uncommon.

I want to improve the insulation. Currently the second floor walls are all filled with paper-backed batts, bulging thicker than the depth of the 4” walls. But where they are exposed in this lower attic, the paper backing is deteriorated to the point that simply touching the paper turns it to dust. In these spaces it is evident that someone at one time had insulation blown-in insulation for the exposed ceilings of the first floor. Even so, it is still quite lower than the tops of the joists. Insulation was also blown in the real attic, and now it has filled the air gap under the roof, preventing air circulation.

I thought I would run another layer of insulation over the exposed backsides of the second floor walls, maybe using one of the brands that come pre-sealed in a vapor barrier. I would run them perpendicular to the old batts, and simply cover up the crumbling paper, and taping between the rows. It was suggested that it would be better to simply tack up a vapor barrier or Celotex panel, but I would have to cut the Celotex down quite a bit from a full sheet just to get it in the spaces. Besides, I’m not sure of the R-value of 45-year-old insulation, and I would not be able to put up a vapor barrier everywhere.

For the ceiling of the fist floor, I would simply lay attic batts. Unless someone thought a vapor barrier was in order too. As far as the blocked air gaps, I haven’t a clue. I can’t get those special air-gap panels to slip in due to the roofing nails. I did manage to get a length of PVC pipe inserted, thinking I would simply insert a bunch everywhere, but I believe that would crush the insulation. A cardboard tube would be too flammable.

Any suggestions? Thanks in advance!!!