BACKGROUND: We noticed drywall water damage at the base of a 1958 bedroom window about 6 weeks ago. Initial moisture readings from when we first found it are attached as picture 1; a large swath of this wall read as either elevated or slightly elevated. After having several moisture remediation and window companies out, we suspect the cause is some combination of failed exterior caulk/flashing, the sill nosing sloping toward the window instead of away, and clogged weep holes along the window tracks. We've had a plastic tarp covering the exterior window opening since this was first noticed.
I cut into the drywall myself after getting a negative asbestos test on the material. I found staining on the back of the drywall and on the wood behind it (which is possibly structural sheathing given the home's brick veneer construction, but that's my best guess, not confirmed).
DATA POINTS:
- Current moisture reading on the exposed wood (likely sheathing): ~10% (dry)
- Current moisture reading on the surrounding intact drywall: notably higher
- Three restoration companies gave mixed reads from photos of the opening. One said proceed carefully if under 10 sq ft, one said stop entirely, one confirmed it's mold but didn't weigh in on DIY-ability.
- Professional remediation quotes ranged roughly $1,400–$3,500 depending on scope.
CURRENT PLAN:
- Treat as DIY if the affected area stays under 10 sq ft (per EPA guidance) and the exposed wood passes a basic structural test (firm when poked with a screwdriver/awl = clean and treat; soft/crumbly = stop and call a pro)
- Full containment (plastic sheeting, sealed room, exhaust fan pointing out a second window in the room), proper PPE (P100 respirator, HEPA vacuum)
- Clean/treat with Concrobium if the wood is structurally sound; don't remove the sheathing itself
- Let it fully dry, then reinstall drywall
HONEST CONTEXT: We just paid for a full roof replacement and still need to replace several windows, so I'm trying to save where I can by doing this myself, but I want to be careful not to talk myself into the cheaper option just because money's tight right now.
QUESTIONS:
- Based on the photos, does this look DIY-manageable, or should I just hire a professional? Or is it genuinely hard to tell without opening the wall up further?
- The wood shows surface staining but tests dry at 10% -- does that track as "past moisture, now under control," or am I being too optimistic?
- Anything else specific you'd check before deciding to proceed vs. call a pro?
I recently remediated some water intrusion in my crawlspace myself and it went well, so I have a reasonable degree of confidence tackling this too, but feel free to give me a reality check if I'm missing something. Appreciate any advice. Thanks!