I have an old brick house that has been stripped of all walls except the outside brick wall and the open stud wall. I want to seal all air holes from the inside and install insulation in between the stud wall and the brick wall. How should I seal the air holes, and what kind of insulation should I use?
Essentially, you want to do the job backward, starting with the brick wall and working your way in. The problem is that your stud wall is already up and you can't attach anything to the outside of it. First you must understand that it is necessary to have a 2.5 cm (1 in.) air space between the brick and the rest of the wall. This space allows water to drain out of the wall and allows the brick to dry. That is why it is not wise to shoot any of the insulating foams right up against the brick. Make sure there are flashed holes at the bottom of the wall to drain the wall outdoors. Your problem is that the wind will move around in that space. Normally there is a weather barrier, such as building paper, or an air barrier, like house wraps, separating that air space from the sheathing and stud wall. So your challenge is to create a barrier that does not touch the brick, will be waterproof but permeable, and not let the air blow into the fiberglass. Try squeezing in some rigid foam panels between the studs. (Treat the exposed side of the studs with wood preservative before squeezing in the panels.) Then fill the wall with fiberglass and finish with a good vapor barrier.