How I put in a solar attic fan (and what I’d do differently next time)

Sometimes those little details are what save you money (and sweat) in the long run.

That’s spot on. I’ve seen folks rush through the install and end up with leaks or rattling fans after the first storm. One thing I’d add - don’t underestimate how much difference a good flashing job makes, especially if your roof isn’t perfectly flat. Also, I learned the hard way that caulking in the midday sun just doesn’t set right... early morning was way easier.

I’m glad I’m not the only one who found out about caulking the hard way... mine turned into a sticky mess and I had to redo it. The flashing tip is a good call, too. My roof’s got a weird slope and I didn’t realize how much water could sneak in at the edges. It’s wild how much those little steps matter - definitely learned to slow down and double-check things, even if it means spending an extra hour up there.

That caulk tube can be a real trickster - either too runny or turns into concrete before you’re done. I’ve seen some wild water trails on odd roof pitches, too. Flashing’s the unsung hero, honestly... most leaks I find are from folks skipping that step or rushing it.

That’s the truth about caulk - either you’re racing the clock before it sets up or you’re chasing drips down the shingles. I’ve had tubes go from soup to rock in the same afternoon, especially if the sun’s out. I’m still figuring out the sweet spot for working time.

Flashing gets overlooked way too often. I was helping on a job last fall, and the homeowner had tried to DIY a vent install without any step flashing. Water found its way in, even though the caulk bead looked perfect. It’s wild how water just finds every shortcut. Did you end up using aluminum or that flexible flashing tape? I’ve seen both, but I’m not sure which holds up better over a few seasons.

Also, curious if you ran into any issues with the roof pitch and getting the fan to sit flush? Some of those solar models don’t love steep slopes. I’m still learning all the tricks, but it’s cool hearing what actually works out in the field.

I’ve seen more leaks from skipped flashing than just about anything else. Folks trust caulk way too much - seen it peel up after one hot summer, and then you’re back to square one. I stick with aluminum flashing every time, even if that tape stuff is tempting for quick fixes. Had a job last spring where the pitch was so steep, the solar fan wanted to sit at a weird angle and the gasket barely made contact. Ended up having to shim it a bit and double-check the seal. Not perfect, but better than trusting gravity alone.

Folks trust caulk way too much - seen it peel up after one hot summer, and then you’re back to square one.

Man, you nailed it. I’ve seen more “miracle caulk” jobs fail than I can count, especially after a Texas summer. Aluminum flashing’s saved my bacon a few times - tape and caulk just don’t cut it long-term. That weird angle on steep pitches is always a pain, too. Shims are underrated, honestly. Gravity’s got its limits when water’s involved...

- Seen it a hundred times - folks rely on caulk as their main line of defense. Doesn’t matter what the label says, it’ll crack or peel after a couple seasons, especially on a south-facing roof.
- Last install I checked, homeowner used a bead of caulk and called it “good for years.” Next spring, water stains everywhere. Flashing was barely tucked under the shingles, too.
- For solar attic fans, I always recommend overdoing the flashing. Run it up under at least two shingle courses, and never trust just a surface seal. If the roof slope’s steep or you’ve got weird angles, pre-bend the flashing or use a flexible kind - saves a ton of cursing later.
- Shims help, but I’ve noticed folks forget to check how water actually runs. Gravity’s tricky - water finds the tiniest gaps. I’ll sometimes do a quick hose test before calling it done.
- Tape might work for a window, but I wouldn’t trust it on a roof in Texas or anywhere with wild temp swings. Caulk’s for detail work, not primary waterproofing... unless you like repeat visits.
- If you’re up there, double-check nail placement. Seen leaks just from nails driven too close to seams. It’s the little stuff that gets you.

I get where you’re coming from about caulk not being a main defense, but I’ve actually had decent luck with some of the higher-end polyurethane sealants - at least as a backup layer. Maybe it’s just our milder winters here, but I haven’t seen the same peeling issues unless the prep was sloppy. Still, I agree that flashing is king, especially on older roofs where you never know what you’ll find under those shingles. I do think folks sometimes overcomplicate it, though - if you’ve got solid overlap and a good seal, you don’t always need to go wild with extra layers. Just my two cents.

- You’re spot on about prep making or breaking it. Even the best sealant won’t save you if the surface isn’t clean and dry.
- I’ve seen plenty of jobs where folks relied too much on caulk, then wondered why water found its way in a year later.
- Flashing really does most of the heavy lifting, especially with weird roof angles or older homes where nothing’s square.
- Agree - sometimes people go overboard with layers and end up trapping moisture instead of keeping it out. Simple and solid usually wins.
- Sounds like you’ve got a good handle on it. Just keep an eye on those seals every couple years...they can surprise you.

- Had a job last fall where the homeowner skipped flashing around their new solar fan - just relied on a thick bead of caulk. Looked fine at first, but after one winter, water started sneaking in and stained the ceiling.
- I always double-check for shingle overlap and make sure the flashing tucks under properly.
- Sometimes folks get nervous and pile on too much sealant... seen that trap moisture more than once.
- Curious - did you run into any issues with the roof deck being uneven? Older houses can be tricky that way.
- For me, slow and steady wins - measure twice, cut once, and don’t rush the waterproofing steps.

- Had a similar issue with uneven roof decking on my 1960s ranch. Ended up using some extra roofing felt to help level things out before installing the fan.
- Flashing is a must - learned the hard way after a cheap vent install years ago. Caulk alone just doesn’t cut it, especially with freeze/thaw cycles.
- I’m all for saving money, but skipping steps usually costs more in repairs later.
- Noticed too much sealant can actually make leaks worse if water gets trapped underneath. Less is sometimes more.
- If you’re working with an older roof, I’d budget a little extra for unexpected fixes... those surprises always pop up.

Title: Solar Fan Install Surprises - Anyone Else Battle Uneven Roof Decking?

Uneven decking is such a pain, right? I’ve run into that on more than a few jobs, especially with older ranches like you mentioned. Sometimes it feels like those old boards are just daring you to find a flat spot. Did you have to feather the felt out in layers, or did one extra sheet do the trick for you? I’ve had to get creative with shims under the felt once or twice when things got really wavy.

Totally agree on the flashing. I still remember my first “quick fix” vent job - thought a fat bead of caulk would do it. Next spring, water found its way in and I ended up replacing a chunk of ceiling drywall. Lesson learned... Water always wins those battles if you give it half a chance.

I’m curious how much sealant you ended up using. I’ve seen folks go wild with it, thinking more is better, but like you said, it can actually backfire. Had a homeowner call me after a DIY attempt where they basically made a little pond under the vent with all that goo. Sometimes less is more, especially if your flashing’s solid.

Budgeting extra for surprises is just smart with older roofs. Last month, I opened up a section on a 70s split-level and found a whole mess of rot around an old chimney - wasn’t on the estimate, but you can’t just leave it. Do you try to prep for those “while I’m up here” moments, or just roll with it as they come?

Curious if you noticed any noise from the fan after install? Some of the solar ones hum a bit, depending on how tight the mounting is and if the roof’s got any bounce. I’ve had to add extra screws or even some foam gasket material to quiet things down.

Would you do anything different with the install next time? I’ve started using synthetic underlayment instead of felt on some jobs - costs a bit more, but seems to handle moisture better, especially on low-slope roofs.

Always something new to learn with these old houses...

Man, you nailed it about the old decking. I swear, mine felt like walking on a rolling hill up there - nothing flat about it. I did the “extra felt and cross your fingers” method, but if I ever do it again, I might try your shim trick. As for the sealant, I was stingy - just enough to make the flashing happy, not enough to build a birdbath. And yeah, the fan did have a weird hum at first. Ended up wedging a bit of leftover foam under one corner, and that mostly killed it. Next time, I’m definitely budgeting for “surprises”... my wallet still hasn’t forgiven me for that hidden patch of rot under the shingles.

- I’m right there with you on the “surprise” costs. Thought I budgeted enough, but that hidden rot ate up my cushion fast.
- My decking’s not exactly flat either - makes me wonder if shims are worth the hassle or just masking a bigger problem.
- Did you notice any leaks after using less sealant? I keep hearing mixed advice - some folks say more is better, others warn about trapping moisture.
- That hum from the fan would drive me nuts. Did the foam fix last, or did it creep back over time?
- Curious if anyone’s tried those newer self-leveling flashing kits... are they actually easier, or just another gimmick?

Hidden rot is the worst - mine showed up right after I thought I was in the clear, too. Ended up pulling up way more decking than planned. About the shims, I tried them on a low spot and honestly, it felt like a band-aid. If your decking’s sagging or soft, I’d say it’s worth biting the bullet and replacing that section. Otherwise, you’re just propping up a problem that’ll come back to haunt you.

On the sealant debate, I went lighter than most guides suggested (figured less gunk = less trapped water), and so far, no leaks. But I’m in a pretty dry climate, so maybe that’s why. If you’re somewhere humid, I’d probably err on the side of caution.

The fan hum - yeah, that drove me nuts too. The foam trick worked for a few months, but then the noise crept back. Ended up swapping out the mounting screws for rubber washers, which helped more than the foam did.

Self-leveling flashing kits... tried one on a shed roof. It was easier to apply, but honestly, it didn’t seem any better than old-school flashing and caulk. Maybe worth it if you’re in a rush, but not a game-changer.

I get where you’re coming from on the shims, but I’ve actually had decent luck with them in a couple spots - mainly where the dip was minor and the rest of the decking was still solid. I wouldn’t use them over big soft patches, but for a little sag between rafters, it bought me a few extra years before a full tear-off. Maybe I just got lucky with my roof’s age and the dry climate here.

On sealant, I’m on the other side - I went heavier than most guides suggested, especially around the fan base and flashing. Yeah, it’s messier and takes longer to cure, but after one bad storm season, I’d rather deal with extra cleanup than water stains on my ceiling. I do agree about not overdoing it to the point where water gets trapped, though.

As for the self-leveling flashing kits, I actually liked them for weird angles - my roof’s got a funky pitch, and the kit filled gaps better than regular caulk. Not perfect, but less hassle for me. Guess it depends on how much time you want to spend fussing with it.

I hear you on the shims - if the dip’s minor and the rest of the deck is solid, I’ve seen them hold up for a while too. Wouldn’t trust them on anything spongy, though. On sealant, I probably lean more toward your approach after seeing a neighbor’s attic get trashed from a tiny leak around his fan base. Cleanup’s annoying, but water damage is worse. Those self-leveling kits are a lifesaver for oddball pitches... I had to deal with a 7/12 slope and regular caulk just didn’t cut it. Curious if you noticed any shrinkage with the kit over time? That’s the only thing that bugged me.

Those self-leveling kits are a lifesaver for oddball pitches... I had to deal with a 7/12 slope and regular caulk just didn’t cut it. Curious if you noticed any shrinkage with the kit over time? That’s the only thing that bugged me.

I’ve run into the same issue with shrinkage, especially on the south-facing side of my roof where it gets hammered by sun most of the day. The first year after installing my solar fan, I checked the sealant every couple months and noticed some minor pulling away at the edges - nothing catastrophic, but enough to make me nervous. Ended up running a second bead around the base after about 10 months, just to be safe. Not sure if it’s the brand or just our climate (humid summers, cold winters), but I’d say expect a little movement.

On shims, I’m right there with you - if the deck is solid, they’re fine for minor dips. Tried them once on an older section where the plywood was borderline spongy and regretted it. Ended up having to pull everything up and sister in new supports. Lesson learned: shims are not a fix for structural issues.

Water intrusion is my biggest worry too. My neighbor had a similar situation - tiny leak around his attic vent that went unnoticed until mold started showing up in his insulation. The cleanup cost him way more than just doing a careful install would have. I’d rather spend an extra hour fussing with sealant than risk that kind of headache.

One thing I wish I’d done differently: used a flashing boot designed for steeper pitches instead of trying to make a universal one work. The self-leveling stuff helped, but there’s only so much you can do when the fit isn’t perfect. Next time, I’ll spend the extra $20 for something made for my roof angle.

If you’re budget-minded like me, it’s tempting to cut corners on materials, but in my experience, water always finds its way in if you give it half a chance. A little extra upfront goes a long way toward peace of mind down the road.

Had a similar adventure last year - thought I could outsmart gravity and use a “universal” flashing on a 9/12 pitch. Spoiler: water laughed at me. Ended up crawling back up there with a tube of sealant and a very bruised ego. Next time, I’m just buying the right boot from the start. Also, totally agree on shims - tried to save a buck, wound up spending my Saturday fixing the mess. Sometimes cheap is expensive...

Been there with the “universal” flashing - mine claimed it’d fit anything, but apparently my roof didn’t get the memo. I tried to save a few bucks too, thinking sealant would do the trick. It held up until the first real rain, then I got a nice drip right over my workbench. Lesson learned: sometimes you just have to buy the part that’s actually made for your roof pitch.

I still get tempted by those “one size fits all” deals, though. Hard not to when you’re staring at the price tags in the aisle. But yeah, after spending half a Saturday crawling around up there (and nearly sliding off), I’m starting to think my time is worth more than I realized.

Curious if anyone’s had luck with those adjustable boots? Or is it just better to bite the bullet and get the exact match? My attic fan install is next on my list, and I’d rather not repeat last year’s water feature...