Moisture meters and IR scans can help, but even then, water finds crazy paths under these membranes.
Not sure I totally agree that leaks almost always start at flashing and penetrations. I’ve seen a few cases where ponding water in the field eventually wore down the membrane, especially on older roofs with poor drainage. Sometimes the obvious spots aren’t the only culprits.
I’ve run into the same issue with my old modified bitumen roof—leaks showing up in places that made zero sense, even after checking all the usual suspects like flashing and seams. In my case, it turned out ponding water had slowly broken down the membrane right in the middle of the field. I ended up using a cheap moisture meter from Amazon and marking out the wet spots, then patching those areas with a cold-applied repair kit. Not a perfect fix, but it bought me a couple more years before I had to budget for a full replacement. Sometimes it’s just about buying time without breaking the bank...
Sometimes it’s just about buying time without breaking the bank...
Totally get that. Field leaks can be sneaky, especially with older mod bit roofs. I’ve seen water travel under the membrane and pop up way far from where it actually gets in, which makes tracking it down a pain. Moisture meters are underrated for this, honestly—nice call using one. If you’re seeing ponding, sometimes it’s worth checking if your drains are just a little clogged up or if there’s some low spots you could build up with extra layers. Not a forever fix, but it can help stretch things out a bit longer.
Yeah, tracking down leaks on a flat roof can be a real headache. I’ve dealt with a few where the water found its way in through a tiny split, then traveled halfway across the building before showing up inside. I agree about checking drains—sometimes it’s just a pile of leaves causing all the trouble. One thing I’d add: don’t underestimate how much damage those “temporary” patches can do if you leave them too long. I’ve seen insulation rot out from under folks who kept layering on quick fixes. Sometimes it’s worth biting the bullet and getting a pro to do an infrared scan, especially if you’re managing multiple units or tenants are getting cranky.
- Been there, done that. My flat roof’s leaked on and off for years—always seems to show up in a different spot than where the water actually gets in.
- Drains are sneaky. Last time, it was a tennis ball (no clue how it got up there) clogging mine.
- I’ve tried those “quick fix” patches too. They’re fine for a week, then you’re back up there with a bucket. Not worth it long-term, especially if you forget about them (guilty).
- Infrared scan sounds fancy, but the quotes I got were more than I wanted to spend. Ended up just crawling around the attic with a flashlight after rain. Not fun, but found some soggy insulation and traced it back.
- If you’re on a budget like me:
- Clear drains/gutters every fall (and after storms)
- Check for tiny splits or popped seams—those things hide
- Don’t pile on the tar unless you’re desperate
- If you keep chasing leaks and can’t find the source, maybe time to save up for a real repair instead of patching forever
- Honestly, sometimes it feels like the roof’s just trolling me... but at least I get my steps in.
