That spray stuff is a total lifesaver when you’re in a pinch, but I’ve seen it peel off in sheets once the sun gets to it. Roofing cement’s definitely got more staying power—though I’ve had my fair share of ruined shirts from that stuff. If you’re dealing with a flat roof, sometimes the cement just pools and cracks anyway. I’ve started carrying some mesh fabric to reinforce patches—messy, but it holds up till you can do a proper fix. Temporary’s fine, but nothing beats getting up there and replacing the bad section when you can.
That mesh trick really does buy you some time, even if it’s a pain to get it to lay flat. I’ve watched guys swear by that spray, but I’ve seen it bubble up and peel after a couple hot days, too. Cement’s messy, but at least it feels like you’re actually doing something. Flat roofs are their own beast—sometimes I think they just want to leak no matter what you do. Still, patching it up right away beats letting water in. You’re right, though—nothing beats a real fix when you can swing it.
Flat roofs are their own beast—sometimes I think they just want to leak no matter what you do.
Ain’t that the truth. I’ve seen more “miracle” patches fail on flat roofs than I can count, especially after a freeze-thaw cycle. One time I inspected a place where the owner had tried three different products in the same summer—mesh, spray, and even some kind of rubberized tape. None of it lasted through the first real storm. Curious if anyone’s had luck with those newer liquid membranes? They claim to flex with the roof, but I haven’t seen one hold up past a couple seasons yet.
Flat roofs really do have a mind of their own. I’ve lost count of the times I’ve crawled up there thinking I’d finally outsmarted the leaks, only to find a new drip forming right over my favorite chair a month later. Those liquid membranes you mentioned—I tried one last spring (some “elastomeric” stuff from the hardware store). It went on easy, looked promising, and even survived a couple of summer storms. But once winter hit and we got that freeze-thaw rollercoaster, it started peeling up at the seams. Not catastrophic, but definitely not the miracle cure they make it sound like.
I’m in the Midwest, so we get everything from blazing sun to ice dams. I’ve noticed that no matter what product I use, the edges and corners are always the first to go. Maybe it’s just my application technique (I’m not exactly a pro), but I wonder if those spots just can’t flex enough when things expand and contract. Has anyone had better luck with reinforcing those trouble areas? I’ve heard some folks swear by using mesh tape under the liquid stuff, but then you’re back to patching and hoping for the best.
One thing I did try that seemed to help—at least for a season—was making sure all the drains were totally clear before applying anything. Seems obvious, but I used to just slap on sealant and hope for the best. Now I spend more time cleaning than patching, which is probably how it should be... but it’s not exactly fun.
Curious if anyone’s found a combo that actually lasts more than two winters? Or is this just the price we pay for having a flat roof in a place where winter refuses to quit?
I hear you on the frustration with those edges and corners. In my experience, though, I’m not convinced it’s just about the flexibility of the membrane or even your application technique. A lot of the time, what I see during inspections is that the underlying substrate at those trouble spots isn’t as sound as folks think—sometimes there’s a bit of rot or old patchwork that doesn’t bond well with new coatings. That can make even the best products peel up once things start moving with temperature swings.
Mesh tape can help, but only if you’re really prepping those areas—grinding down loose stuff, drying everything out, and priming if needed. Most people (myself included when I’m in a hurry) skip a few steps and then wonder why it fails by February.
Honestly, I’ve seen better long-term results when people use a combination: reinforce seams with fabric or mesh, use a high-quality primer, and then apply two coats of membrane. It’s more work upfront, but seems to hold up longer in Midwest winters. Still, nothing’s truly permanent on a flat roof around here... sometimes it feels like we’re all just buying time until the next thaw.
