"Lesson learned: investigate gently first, destructive panic second..."
Been there myself—patched spots can really fool you. Curious, has anyone tried moisture meters to confirm leaks before cutting? Wondering if they're accurate enough to justify the cost for occasional DIY use...
Moisture meters can be handy, but honestly, they're not always foolproof. I've seen them give false positives if there's metal or wiring behind drywall, or even just dense insulation. Before dropping cash on one, try the old-school method first: pencil-mark the suspicious spot, snap a quick photo, and check back after a rainy day or two. If it grows or darkens, you've got your answer without spending extra money. Just my two cents...
Totally agree about moisture meters being a bit hit-or-miss sometimes. Had a job last year where the homeowner was convinced they had an active leak because their meter kept lighting up like a Christmas tree. Turned out, after cutting into the drywall (which nobody enjoys doing unnecessarily...), it was just some old metal ductwork behind the wall throwing off the readings.
Your pencil-mark trick is solid advice. Another thing I've found helpful is checking the texture of the stain itself. Fresh leaks usually feel slightly damp or cool to the touch, while older stains tend to be dry and brittle, sometimes even flaky. Also, older stains often have a defined edge, whereas newer ones might have blurry or spreading edges.
But yeah, nothing beats patience and observation. Sometimes it's tempting to jump straight into expensive tools or invasive inspections, but giving it a few days and keeping an eye on things can save you a lot of hassle—and drywall patching—down the road.
Definitely agree patience is key, but sometimes waiting isn't an option—like when I moved in last year and found a suspicious stain on the ceiling after a rainstorm. Couldn't tell if it was fresh or old, so I lightly traced around the edges with pencil (like you mentioned). Sure enough, next storm it expanded beyond my mark... ended up being flashing around the chimney. Saved me from cutting drywall prematurely though, thankfully. Sometimes the simplest methods are best.
"Couldn't tell if it was fresh or old, so I lightly traced around the edges with pencil (like you mentioned)."
That's a neat trick, hadn't thought of marking it like that. Reminds me of when I was helping my uncle with his roof last summer—we found a stain in the attic and couldn't figure out if it was active or ancient. He had this idea to tape a piece of paper towel right under the spot. Sure enough, next rainstorm, the towel got damp and we knew exactly where to look. Sometimes low-tech really is best...
