I actually tried that slow-hose trick after a few storms last fall when water started dripping into my laundry room. My house is only a few years old, but the roof’s totally flat and I couldn’t spot anything obvious. I never thought to use dye though—just crawled around with a flashlight, which was... not fun. I did find a tiny split near a pipe boot, not at the seam, which surprised me. That said, the idea of adding dye sounds messy but probably way more effective than what I did.
I did find a tiny split near a pipe boot, not at the seam, which surprised me.
That’s exactly where mine was hiding too—right by the vent, not even close to the seams. I tried the dye thing once (food coloring in a bucket of water), and yeah, it got a bit psychedelic up there, but it actually helped spot the leak faster than crawling around with a flashlight. If you try it, just go easy on the dye unless you want your gutters looking like a tie-dye project for weeks... Learned that one the hard way.
Ha, the dye trick sounds way more fun than my method, which was basically just staring at the ceiling and hoping for a miracle. I swear, these leaks are like ninjas—always sneaking around where you least expect. I’m glad you found yours. Honestly, I was convinced mine was coming from the seams too, but nope, tiny crack by the vent. Makes me feel a little less clueless knowing it’s not just me. Flat roofs are a whole different beast... hang in there, you’re not alone in the leaky roof club.
Flat roofs really do have a mind of their own—I've seen so many cases where the leak's nowhere near where the water actually shows up. Had one last year where the culprit was a pinhole in the flashing, hidden behind a clump of leaves. I get why folks focus on seams, but in my experience, penetrations (vents, chimneys, skylights) are usually the real troublemakers. Honestly, water’s sneaky—capillary action can pull it sideways for feet before it drips inside. Dye tests are useful, but sometimes you’ve just gotta get up there during a rainstorm and watch where it’s coming in. Not fun, but beats guessing.
Funny you mention dye tests—I tried that once and the water still managed to find a way around where I thought it’d show up. My last leak was actually coming in through an old satellite dish mount, of all things. Have you ever had to peel back part of your roof just to track a leak? I’m always torn between patching what I see or just biting the bullet and redoing a whole section.
