Air sealing a 1928 Brick on block masonry home
I am trying to make my 1928-ish structural masonry home more comfortable (1st) and energy efficient (2nd). My current aim is for better air sealing as additional insulation doesn’t seem to be a non-destructive option at this point. Exterior cladding over the brick facade isn’t at the top of my (wife’s) wish list, and tearing out the original plaster isn’t at the top of mine.
As far as I can tell, the construction of my foundation and load bearing exterior walls is: a double course of red clay structural tile for the below grade foundation, and a single course of clay tile with brick facing for the 1st and 2nd story exterior walls. The floor joists are let into the clay tile and mortared into place. The interior finish is 1×2″ furring strips fastened to the mortar of the clay tile, then traditional lath (1/4″?) and about approx. 3/4″ of original plaster.
I get major air leakage anywhere the interior finish has a discontinuity. Any electrical outlet, the gap between baseboard and flooring, poorly caulked window trim. We’re talking about blow-your-hair-back breeze. I can’t see exactly how a double course masonry wall would be so porous, but it is as it is.
i plan to seal any penetration of the interior finish, but my concern is the airflow around the masonry. I know there should be an air gap for the masonry to dry to the inside – is this the air gap between the two courses of brick/block? Or does the wall rely on the 1″ furring strip on the inside?
Would I be able to air seal at the top and bottom of the cavity created by the furring? There is K&T wiring in this void so filling it with cellulose/foam/etc is not a good option.
See my diagram for a cross section view of the wall (my best guess at least). Green arrows is airflow I want to eliminate. Blue arrow is the airflow to dry the wall cavity – if a cavity here actually exists.
Also there seems to be a lot of airflow in any framed-out interior void, such as this archway pictured below. Is there a limited-destruction way to seal air from blowing around the interior walls of the house?
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