jackbird
10-23-2010, 06:43 AM
(Two-story brick colonial, Philadelphia Suburbs, built 1950, gas-fired hydronic heat)
My house has structural masonry walls, with an exterior layer of brick, an interior layer of a combination of cinderblocks and brick, a 3/4" air gap with furring, and an interior wall consisting of 3/8" drywall attached to 3/8" cement board with a 1/16" plaster skim on the interior surface. There is no wall insulation.
I'm sealing the penetrations in my attic and doing the rest of the preparations for blowing in cellulose to R-38. In the process I've discovered that the tops of the exterior walls are simply open - I can see the furring strips and look right down to the base of the second floor with a flashlight. This is very handy for running wires, but strikes me as a major, or perhaps THE major air leak for the house.
If I seal the tops of the walls with spray foam, though, am I screwing up the moisture management of the walls? If so, what should I do instead to keep my second-floor walls from filling up with cellulose?
My house has structural masonry walls, with an exterior layer of brick, an interior layer of a combination of cinderblocks and brick, a 3/4" air gap with furring, and an interior wall consisting of 3/8" drywall attached to 3/8" cement board with a 1/16" plaster skim on the interior surface. There is no wall insulation.
I'm sealing the penetrations in my attic and doing the rest of the preparations for blowing in cellulose to R-38. In the process I've discovered that the tops of the exterior walls are simply open - I can see the furring strips and look right down to the base of the second floor with a flashlight. This is very handy for running wires, but strikes me as a major, or perhaps THE major air leak for the house.
If I seal the tops of the walls with spray foam, though, am I screwing up the moisture management of the walls? If so, what should I do instead to keep my second-floor walls from filling up with cellulose?