Proposed approach for fixing brick/poly wall issues
My house was built in Kentucky in 1996. Exterior walls were built with the following order/characteristics:
— Full brick siding – rope-style weeps but no vents
— 1/2-inch air gap between brick back and Tyvek – there’s lots of trash mortar, much of it smushed flat against Tyvek; gap is open at top, good air flow in soffit
— Tyvek – probably lapped not taped ()
— OSB sheathing
— 2×6 studs with R-19 Fiberglas bats
— drywall with latex paint
After we took of the perimeter drywall, we observed moisture droplets on the insulation side of the poly in areas where windows had leaks but not in areas where windows did not have leaks. I assume this means vapor drive from the outside has been a minimal issue compared to water injected into the tight walls via the leaks. Minor mold and staining was found on the bottom plates and OSB under some windows and the next 2-3 stud spaces.
Moisture was NOT observed on the drywall side of the poly, and we saw no water damage on the back of the removed drywall.
My planned remediation steps are:
— Replace windows (which have other problem too), improve flashing and caulking
— Redo brick ledges to ensure adequate slope for water shedding
— Add venting to brick layer at or just above weep line.
— Add sealant to face of bricks — MAYBE
— Tear out all the perimeter drywall, remove poly and insulation.
— Remediate mold — remove or abrade damaged or overtly moldy wood, spray everything with vinegar, let dry; then spray with Borax solution, let dry thoroughly.
— Add 2″ of closed-cell spray foam insulation
— Add unfaced R13 Fiberglas bats in remainder of stud space
— Add drywall with latex paint — no poly!
— Clean or repaint all interior walls and surfaces
— Clean/disinfect HVAC ducts
Questions and comments on logic:
(1) Does the above approach look sound?
(2) Brick venting: I’ve looked at brick-sized vents — intended to replace an entire brick every so often. Some products are not very well designed; others are well done but for various reasons won’t work for me. My current thinking is to take out a vertical mortar line every second or third brick — setting the bottom of the gap on an angle to keep water from running in — and then add stainless steel wool, brass wool, or a tube of aluminum screen in each hole to keep wasps and mice out. Any thoughts on how many mortar joints I should take out to foster the needed air flow, given the restricted air gap I’m stuck with?
(3) Brick sealing: In the few spots where we’ve removed test patches of OSB, the brick itself (or at least the air-gap space) has a slightly moldy smell, though there is no visible mold. Perhaps this is due to moisture from vapor drive? It seems to me that sealing the surface of the brick and simultaneously improving the air flow behind the brick will help keep the body of the brick from getting damp, thus reducing the tendency to mold, and will minimize the amount of moisture getting to the OSB as well. Agree?
Thanks for any insights you can share.
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