Solar attic fan install was supposed to be easy... right?

Cutting into a roof always feels like defusing a bomb to me - one wrong move and you’re sweating bullets hoping you didn’t just create a future waterfall in your attic.

That’s a pretty accurate description. Last time I installed a solar fan, I thought I had everything sealed tight - used what I thought was enough flashing and high-end sealant. Then we got one of those sideways rainstorms and, sure enough, I found a drip right above my workbench. Those old asphalt shingles really do curl up and fight you. Next time, I’m tempted to just tarp the whole roof until I’m done...

Those old asphalt shingles really do curl up and fight you.

That’s the real headache, especially if the roof’s got a few years on it. When I did my first solar fan, I underestimated how much those curled shingles would mess with the flashing. Ended up having to lift and re-seat a couple just to get a decent seal. Tarping helps, but honestly, sometimes it’s just about picking a dry stretch and working slow. If you haven’t tried using a flexible flashing tape under the metal flashing, it can help bridge those uneven spots. Not perfect, but it saved me from chasing leaks later.

Those curled shingles are a pain, no doubt. I ran into the same thing last fall - thought I could just pop the fan in and be done, but nope, had to pry up half the row just to get the flashing to sit halfway right. I’m not totally sold on that flexible tape though... tried it once and it didn’t stick as well as I hoped after a week of rain. Maybe my roof’s just too far gone? Either way, you’re right about picking your weather window and taking it slow. Rushing is how you end up with leaks and regrets.

Flexible tape never really did it for me either, especially on older shingles that just don’t want to lay flat. I’ve had better luck with the old-fashioned metal flashing and a healthy dose of roofing cement, but even then, if the shingles are curling up, it’s a fight. At some point, patching starts to feel like putting lipstick on a pig. Have you thought about whether it’s worth doing more repairs or just biting the bullet and replacing the whole section? Curious if anyone’s tried those newer peel-and-stick underlayments on a roof that’s already seen better days...

At some point, patching starts to feel like putting lipstick on a pig.

That’s the truth. Once shingles start curling, you’re basically fighting gravity and time. I’ve seen peel-and-stick underlayments used as a last-ditch effort, but on an old roof, they’re more like a band-aid than a cure. If you’re already seeing widespread curling or cracking, it’s usually more cost-effective (and less headache) to replace the whole section. Otherwise, you’ll just be chasing leaks every season.

I get where you’re coming from, but I’ll admit I tried patching a few spots before biting the bullet on a full tear-off. My shingles were curling at the edges, and every time I thought I’d fixed one leak, another would pop up after a heavy rain. The solar attic fan install was the last straw - cutting into old, brittle shingles just made things worse. If your roof’s already showing its age, especially with curling or cracking, it’s tough to get a good seal around new penetrations. Sometimes it’s just not worth fighting with it anymore... I wish I’d replaced that section before messing with the fan.

That’s the thing with older roofs, right? Once those shingles start curling, it’s like playing whack-a-mole with leaks. I’ve seen folks try to patch around vent installs, but the seal never really holds if the material’s already brittle. Did you ever get any pushback from your installer about the condition of your shingles before they cut in for the fan, or was it more of a DIY job? I’ve had some contractors flat-out refuse to touch a roof if it’s past a certain age - they say it’s just not worth the callbacks.

Also, curious - did you notice any difference in attic temps at all before the leaks started up again? Sometimes I wonder if the hassle is even worth it on an old roof, or if it just opens up more headaches.

You nailed it about contractors steering clear of old shingles - honestly, I’ve turned down jobs where the roof was just too far gone. Once those shingles get brittle and start curling, there’s no good way to guarantee a seal around new penetrations. I get why folks want to install fans for the attic heat, but if the roof’s already on its last legs, it’s kind of a gamble. I’ve seen a few people get some short-term relief on attic temps, but then the leaks start and you’re back to square one... Sometimes patching just isn’t worth the headache if the whole surface is compromised.

Once those shingles get brittle and start curling, there’s no good way to guarantee a seal around new penetrations.

I've run into this exact issue during inspections. Folks sometimes underestimate how much those old, curled shingles can compromise even the best install. I’ve seen a few solar fans done on 25+ year-old roofs, and inevitably, water finds its way in around the flashing. Sure, attic temps drop for a season or two, but then you’re chasing leaks. In my experience, if the shingle field is brittle, adding any roof penetration is just asking for trouble - it’s almost impossible to get a reliable seal. Sometimes it’s better to wait until you can do both jobs together - new roof and fan - rather than patching up problems one at a time.

Sometimes it’s better to wait until you can do both jobs together - new roof and fan - rather than patching up problems one at a time.

Couldn’t agree more with this. I get the urge to add a solar fan for the energy savings, but if your shingles are curling like potato chips, you’re just asking for leaks. I’ve seen folks try to “make it work” with extra caulk or flashing, but water always wins in the end. Honestly, if you’re already thinking about a new roof soon, it’s way less hassle (and waste) to do both at once. Plus, you can look into cool roof options or recycled shingles while you’re at it... might as well go green if you’re re-roofing anyway.

...if your shingles are curling like potato chips, you’re just asking for leaks.

This hits home. Every time I see someone slap a fan on a roof that’s already waving at the neighbors, I just cringe a little. I get it - solar attic fans sound like a win, but if the roof’s already on its last legs, it’s kind of like putting a sunroof on a rust bucket.

Honestly, bundling the jobs is the way to go. Less mess, fewer headaches, and you only have to listen to the hammering once. Plus, you get to geek out over all the eco-friendly options. Ever looked into those reflective shingles? They’re like sunglasses for your house. I went with recycled composite shingles last year - pricey up front, but my summer AC bills dropped.

I know it’s tempting to DIY and patch things up, but water’s sneaky... it’ll find a way. If you’re re-roofing anyway, might as well future-proof the place and keep it green. Feels good knowing you’re not just tossing more stuff in the landfill, you know?

If the roof’s already on its last legs, it’s kind of like putting a sunroof on a rust bucket.

That’s exactly it. I learned the hard way - put a solar fan on my old three-tab roof thinking I was being clever, and two years later I was chasing leaks every time it rained. Ended up having to redo the whole thing anyway, and patching around that fan was a pain.

Bundling is just less hassle. When I finally bit the bullet and did the new roof plus attic fan together, the crew flashed everything in properly and I haven’t had a single drip since. I went with architectural shingles (not as green as composite, but they hold up better in our hail storms here). The reflective ones are interesting, but I was worried about them looking weird in my neighborhood - maybe that’s just me.

DIY patch jobs are tempting, but water always wins in the end. If you’re already up there, might as well do it right and not have to think about it for another 20 years.

That’s a good point about the reflective shingles - I’ve wondered if they’d stick out too much on my block, too. I keep hearing mixed things about how much difference they actually make with attic temps. As for the fan install, I’ve seen a few jobs where the flashing was almost an afterthought, and yeah, leaks were inevitable. Seems like it’s always a tradeoff between getting it done quick and getting it done right. I’m still learning, but every time I see someone try to “just patch it,” it ends up being more work down the line. Water finds every shortcut...

Water finds every shortcut...

Funny, I had the same worry about the shiny look when I put mine in, but you’re right - after a season or two, it just blends in. As for sealing, I learned the hard way that caulk alone doesn’t cut it. What worked for me: peel back the shingles, slide the flashing under, then use roofing cement around the edges before nailing it down. Haven’t had a leak since, and my attic’s way less of an oven now.

That shiny look threw me off too the first time I put one in. My neighbor joked it looked like a UFO landed on my roof, but now you’d never know it’s there unless you’re looking for it. Funny how fast the weather dulls things down.

I totally hear you on the caulk - learned that lesson during a surprise spring storm a couple years back. I’d just slapped some caulk around the edges, figured that was enough, and then came home to a nice little drip right over my workbench. Ended up pulling a section of shingles, doing the whole flashing-under-and-cement routine like you described. Haven’t had a drop since.

One thing I’ve noticed, especially after some of those wild summer storms we get here in Oklahoma, is that even with good flashing and cement, those nails can work themselves loose if you’re not careful. Last year after a big hailstorm, I checked mine and found two nails starting to back out. Might be worth giving yours a look after any rough weather - just in case.

Out of curiosity, did you run into any issues with the fan’s solar panel wiring? My install instructions were pretty vague about routing the wires under the shingles versus over them, and I ended up tucking them under but sealing with extra cement where they exited. Seems fine so far, but I always wonder if there’s a better way.

Also, how’s your attic temp now compared to before? Mine dropped by at least 15 degrees on hot days, which honestly surprised me - wasn’t expecting that much of a difference.

That’s a good point about the nails. I’ve seen that too, especially on older roofs or after a big wind event. I usually go back with screws instead of nails if I have to redo anything - seems like they hold up better over time, at least in my experience. Not sure if that’s overkill, but I’d rather not be up there every season chasing loose hardware.

On the wiring, I’ve always run it under the shingles, but I try to keep the path as short and direct as possible. I use a dab of roofing cement where it exits, then press the shingle down tight. Haven’t had leaks yet, but I do wonder if the cement will hold up long-term with all the freeze/thaw cycles we get here in Kansas. I’ve seen some folks use those little rubber grommets, but I haven’t tried them myself.

Curious - what kind of roof pitch are you working with? Steeper roofs seem to shed water better, but I’ve noticed the wiring can be trickier to hide without making a lump under the shingles.

I get the appeal of screws, but honestly, I’ve seen just as many issues with folks over-tightening them and cracking the shingles or even pulling through after a couple freeze-thaw cycles. Nails (if you go with ring-shank) aren’t always the villain. As for the cement - man, Kansas winters are brutal. I’ve had it turn brittle and flake off after a couple seasons. Those rubber grommets might look goofy, but they’re surprisingly tough, especially if you’re worried about water sneaking in around the wiring. Ever tried a proper flashing boot? It’s not pretty, but it sure beats crawling around with a caulk gun every spring.

Those rubber grommets might look goofy, but they’re surprisingly tough, especially if you’re worried about water sneaking in around the wiring. Ever tried a proper flashing boot? It’s not pretty, but it sure beats crawling around with a caulk gun every spring.

I hear you on the flashing boot. Not the prettiest thing up there, but after dealing with a couple of mystery leaks last winter, I’ll take ugly over wet insulation any day. I used to swear by roofing cement too - until it started peeling up like old sunburn after a few freeze-thaw cycles. Kansas weather just laughs at that stuff.

Funny enough, I’ve had better luck with ring-shank nails than screws on my last install. Screws always seemed like the “pro” move, but I’ve seen more than one shingle split from someone getting a little too enthusiastic with the drill. Nails plus a good flashing boot and those rubber grommets have kept things dry so far.

Honestly, I’d rather have something that works than something that looks perfect from the street. If it means one less trip into the attic during a rainstorm, I’m all for it.

Honestly, I’d rather have something that works than something that looks perfect from the street. If it means one less trip into the attic during a rainstorm, I’m all for it.

Right there with you. After patching the same spot twice with fancy sealants, I gave up and just used a flashing boot and some grommets - hasn’t leaked since. I do think screws have their place, but on my old 3-tab shingles, nails just seem less risky. The Kansas freeze-thaw cycle is brutal on anything that isn’t locked down tight. At the end of the day, dry insulation wins out over curb appeal every time.