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Community and Q&A

Insulating brick veneer – No sheathing or wrap

user-6293159 | Posted in GBA Pro Help on

We are currently remodeling a 1920s bungalow in Louisville, KY. Upon opening up the exterior walls (original plaster), we discovered that there is no sheathing or warp of any kind behind the brick veneer. The original construction of walls was simply brick veneer (corrugated brick ties to studs), air-gap, studs, and plaster walls (no insulation of any kind).

We are going back with drywall for the remodel, but we are not sure how best to insulate the walls when there is no barrier of any kind on the backside of the studs. We want to add something, but don’t want to harm the air-gap needed for brick/mortar nor do we want to create potential to capture/hold moisture in studs/drywall.

Initial input from contractors and installers ranges from installing fiberglass batten, using spray foam (open & closed), and foam board (cut & coble).

Looking for help to understand which insulation options/methods might work and the pros/cons of each when used where the wall construction lacks some of the typical components usually found in brick veneer construction in 1920s.

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  1. user-6293159 | | #2

    To Steve Knapp - Thanks! These are very possible solutions to our situation. I lilke the felt and tyvek approaches (likely use foam in those cases). Only issue we may have is that the brick veneer is not up against the studs as siding usually is, so may have to see how larger gap, felt/tyvek, and foam behave. Worst case, maybe just add strip in middle of bay to keep felt/tyvek form balloning out too much. Then again, felt might hold it's own without support.

  2. user-2310254 | | #3

    Keith. Note that you should use closed-cell spray foam if installing felt or house wrap as the backer material. If you want to use an air permeable insulation, you should install air-tight rigid insulation as the backer material. If budget is a concern, reclaimed rigid foam likely would be more affordable than new foam.

  3. GBA Editor
    Martin Holladay | | #4

    No matter what type of insulation you install, I think you are going to have to start by installing rectangles of a fairly stiff material in each stud bay, toward the exterior of each bay, up against "sticks" or stops. Possible materials to consider are OSB, plywood, or rigid foam. Because your house has no sheathing, and because some water will leak through the bricks, I would use fairly stiff rigid foam if I were you.

  4. Expert Member
    Dana Dorsett | | #5

    If using virgin-stock foam for a cut'n'cobbled backer, 1" Type I EPS (usually sold with facers) is stiff enough for most insulation when supported by spacer to ensure a masonry cavity. With 16" o.c. stud spacing gluing strips of cut up foam board of sufficient depth to either the brick or your cut'n'cobble foam, about 3-4" from the edges of your 1" foam panel (about 8" apart, centered the panel) would be plenty of support even for dense-packing. Foam board construction adhesive would be the right glue if attaching the spacers to the brick, but if you're attaching the spacers you may be able to get away with taping it with housewrap tape every couple of feet, whichever proves to be easiest.

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