Yeah, I’ve run into that too—if the attic isn’t sealed up tight, those fans can definitely end up pulling warm air from the house. It’s wild how just a few gaps around light fixtures or attic hatches can make a big difference. I remember helping a neighbor with an older place, and after they sealed up the attic floor (spray foam around the pipes and all that), the fan actually started doing its job instead of making things worse.
On the flat roof side, totally agree about drainage being a bigger culprit than the fans. Around here (Midwest), it’s usually clogged scuppers or low spots that lead to trouble, not so much the venting itself. And yeah, sometimes you just can’t fight age—membranes get brittle after enough freeze-thaw cycles no matter what you do.
I’m a big fan of adding a layer of insulation when you’re redoing a flat roof anyway. It helps with both heat loss and keeping the membrane from getting too beat up by temperature swings. Just my two cents...
On the flat roof side, totally agree about drainage being a bigger culprit than the fans. Around here (Midwest), it’s usually clogged scuppers or low spots that lead to trouble, not so much the venting itself.
You nailed it—drainage is king with flat roofs. I’ve seen more damage from standing water than from any venting issue. Insulation’s a smart move too, but I’d argue maintenance is just as critical. Even the best membrane won’t last if you’re not clearing debris and checking for ponding after storms. Age gets us all eventually, but a little vigilance goes a long way.
Drainage issues are always the first thing I look for during inspections, especially after a heavy rain or when the snow starts melting fast. One spring, we had a 12-unit building with a flat roof that looked fine from the street, but when I got up there, two of the scuppers were packed with leaves and random junk—probably from windstorms over the winter. Water had pooled in a couple spots and you could see where it had started to seep under the membrane at the seams. The weird part is, the tenants never reported leaks until months later, by which point we were dealing with interior ceiling stains and some insulation damage.
I get why people focus on insulation and venting—energy bills are no joke—but honestly, if you’re not keeping those drains clear, you’re just asking for trouble. Even with newer TPO or EPDM roofs, ponding water will find a way in eventually. I’ve also noticed that some contractors don’t pitch flat roofs quite enough toward the drains, so even a little sag can create a low spot that holds water for days.
One thing I’m still not sure about: how often do most folks actually get up there to check things out? I try to do it every season change, but sometimes life gets in the way. Curious if anyone else has found a good routine that doesn’t involve climbing up there after every storm.
Also—has anyone tried those new leaf guard inserts for scuppers? I’m skeptical they’d hold up through our freeze-thaw cycles, but maybe they’re worth a shot if it saves me a trip up the ladder...
- You’re spot on about drainage being the silent culprit. Most folks don’t realize how fast a little ponding can turn into a big headache, especially with flat roofs.
- Checking every season change is honestly better than what I see from a lot of owners—some go years without a look. Life gets busy, but you’re already ahead of the game just by making it part of your routine.
- I’ve seen those leaf guard inserts in action on a couple of buildings. Mixed bag, to be honest. They do keep out the big stuff, but in freeze-thaw cycles, they can get clogged with slush or ice and actually slow drainage more. If you try them, just keep an eye out after the first few storms—sometimes you end up trading one problem for another.
- The pitch thing drives me nuts too. Even a tiny low spot will hold water forever if the roof isn’t sloped right. I’ve had to call contractors back more than once to fix “flat” roofs that weren’t pitched enough toward the drains.
- One trick I’ve picked up: after a big storm or thaw, I’ll use binoculars from the ground to check for obvious ponding or debris before hauling out the ladder. Not perfect, but it saves a climb here and there.
- Don’t beat yourself up if you miss a check now and then. It’s impossible to catch everything, especially with unpredictable weather. You’re doing more than most by even thinking about it regularly.
Keep at it—your tenants might not notice, but your roof (and wallet) will thank you down the line.
Had a similar issue with leaf guards on a flat roof last winter—turned into a slushy mess and slowed everything down. Anyone had luck finding a style that actually works in snowy areas, or is it just an endless tradeoff?
