Uninsulated brick renovations
I’m working on a project where we most likely will keep the existing bearing brick walls +-12″ uninsulated and the brick exposed. We are in Chattanooga – recently changed to CZ 3!… but in our current code would be 4. The exterior face of the building will definitely remain brick.
I’m having trouble finding any details of best practices for this type of renovation. The contractor is also the owner and will not be going to any lengths to tighten this up nor do I generally have any faith in the local subs to be able to.
Any details to reference? Especially regarding retrofitting openings and air sealing? Are there any decent looking products to seal the interior face of the brick that function as air barriers but not vapor barriers?
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We just finished a retrofit of a double-brick wall building in Santa Fe, NM, zone 6. Moisture not as big an issue here but lots of details and discussion that informed our decisions here: https://www.buildingscience.com/documents/digests/bsd-114-interior-insulation-retrofits-of-load-bearing-masonry-walls-in-cold-climates
We furred our interior walls with 2x3 studs, with 1” air gap to brick, spray foamed 2” continuous on brick and around back of furring studs, and then net and blew the rest of depth. If moisture were more of an issue we would have drilled weep holes through the brick at baseboard height per building science article, but we have a ventilated crawl space with unfaced batts below wood floor and very dry here so avoided that extra labor. For windows we added single pane interior storms, with sills framed into furr out which got sealed by spray foam. There’s still a few specialty shops in the states making relatively affordable wood storms which is what we went with.
FourSevenFive has some passive-house-level details for insulating interior on a masonry building but their details are quite a heavy lift and we couldn’t afford to go this far: https://foursevenfive.com/content/product/smart_enclosure/masonry_retrofit/475_masonry_retrofit_ebook_May_2019_spread.pdf
Good luck !
Twelve inches of brick is probably around R2.4, which isn't nothing, it's probably comparable to a window. If you want to keep the brick exposed what you want to work on is air tightness. The first step is making sure the mortar is in good shape and where the wall meets the roof and floors is sealed. I'd do a blower door before assuming that the brick face itself is going to leak.
Thanks DC. I'd read in a few places that brick tended to be leaky, but it would make sense that this would depend on condition. I doubt I can get them to blower door it, but it would definitely be interesting if I could.
We are replacing the pocketed beams with a ledger at the floor system, so I will need to come up with some details for how those pockets are sealed. The roof to wall will definitely be tricky but good to focus on. The roof structure will remain, but insulation and roofing will be replaced.
I'll still have to spend some free time seeing what I can find on sealing exposed brick vs vapor transmission.