Anyone else tried those mushroom-style roof vents on sheds?

I hear you on the moisture worries. I put in a couple of those mushroom vents last fall after noticing my tools were getting a bit of surface rust, even with a drainage mat under the sedum. Honestly, it helped some, but on those really soggy weeks here (I’m just outside Seattle), I still get some condensation on the inside roof panels. Never actually measured humidity before and after, but it feels less stuffy now. If you’re storing anything sensitive, I’d still keep an eye on it - those vents aren’t magic, especially in our climate.

If you’re storing anything sensitive, I’d still keep an eye on it - those vents aren’t magic, especially in our climate.

- “those vents aren’t magic, especially in our climate.” - yeah, that about sums it up for the PNW.
- Seen a lot of sheds with mushroom vents after storms, and honestly, they help a bit but don’t expect miracles.
- If you’re still getting condensation, might be worth checking for air leaks around the base or adding a powered vent.
- Had a buddy try a dehumidifier in his shed - worked better than any vent, but then you’re running power.
- For anything you really care about (old tools, paperwork, etc.), I’d double-bag or use sealed bins. Learned that the hard way after a wet winter...
- Bottom line: vents help, but moisture’s always gonna find a way in around here.

That’s spot-on about the PNW - humidity just finds its way in, no matter what. I’ve installed a couple of those mushroom vents on my own shed, and while they do help with airflow, I still had to deal with some damp corners last winter. Here’s what worked for me: after adding the vents, I sealed up all the gaps at the base with weatherproof tape and foam. Then, I tossed in a few moisture absorber tubs (the cheap kind from the hardware store). That combo kept my tools dry enough until spring. Definitely agree - if you’ve got paperwork or electronics, sealed bins are non-negotiable. Vents are a good first step, but it’s really about layering your defenses.

Vents are a good first step, but it’s really about layering your defenses.

Yeah, that’s been my experience too. I put in two mushroom vents last fall (I’m just south of Seattle), and they definitely helped with the stuffiness, but I still ended up with soggy cardboard boxes along the wall. Not sure if it’s just the relentless drizzle or if my shed’s sitting in a weird dip, but I had to get creative.

I tried those moisture absorber tubs like you mentioned, but honestly, I went through them pretty fast - maybe every few weeks? I guess it’s better than nothing, but I started wondering if a small plug-in dehumidifier would be overkill for a shed. Anyone tried that route? Seems like it’d chew up some power, but maybe it’s worth it if you’re storing more sensitive stuff.

One thing I did that made a difference: I ran a bead of exterior caulk along the bottom edge where the wall meets the floor. There were a few tiny gaps I hadn’t noticed before, and I think water was wicking in there. After that, the corners stayed a lot drier. I still get a little condensation on the inside of the roof when we get those cold snaps, but nothing like before.

Totally agree on sealed bins for paperwork or anything electronic. I learned that lesson the hard way - lost a box of old photos to mildew one winter. Now everything’s in those gasketed plastic tubs, even if it feels like overkill sometimes.

Kind of curious if anyone’s tried insulating their shed walls or roof to help with this? My neighbor swears by foam board panels, but I’m not sure if that’d just trap more moisture inside. The PNW is just a constant battle with damp, isn’t it...

I hear you on the constant damp - Seattle weather just doesn’t quit. I tried foam board insulation in my old shed a couple years back, thinking it’d help with temperature swings. It did keep things warmer, but I noticed more condensation on the inside of the roof, especially after a heavy rain. Ended up pulling a few panels off to let it breathe better. Ever thought about putting a green roof on your shed? I know it sounds out there, but I added a shallow sedum layer to mine and it actually helped buffer some of the moisture swings. Not a cure-all, but it’s been interesting to see how much less runoff I get now. Wonder if anyone else has gone that route in our soggy corner of the world...