didn’t factor in how much they’d block airflow. Ended up with condensation dripping in winter—total pain.
That’s exactly what happened to my uncle’s shed, except he got mold behind the insulation too. He was convinced trusses were the way to go for easy install, but didn’t realize how much more you have to think about venting with them compared to open rafters. I always thought vents were just for summer heat, but the winter condensation is honestly worse.
Did you try adding any extra vents after you noticed the problem? I’ve seen some people cut in gable vents or even add those little roof turbines, but I’m never sure how much difference they actually make unless you really open things up. Wondering if anyone’s had luck retrofitting better airflow after the fact, or if it’s just one of those “live and learn” situations.
I’ve actually dealt with this in a detached garage I insulated a few years back. Trusses definitely made the build easier, but I underestimated how much they’d mess with airflow. I started with just soffit vents, thinking that’d be enough, but once winter hit, I had the same condensation issues—water spots on the ceiling, and insulation getting damp near the eaves.
I tried adding gable vents after the fact, which helped a bit, but honestly, it wasn’t a night-and-day difference. The real improvement came when I put in a couple of those spinning roof turbines. They’re not pretty, but they move a surprising amount of air, especially if you’ve already got some lower intake vents. Still, if the insulation is packed right up against the roof deck or blocking the airflow paths, even extra vents won’t fix everything.
One thing I wish I’d done from the start was use those foam baffles between the trusses to keep the air channel open above the insulation. Retrofitting them after everything’s in place is a pain, but it made a noticeable difference for me. Mold never got out of hand, but I did have to replace some soggy insulation.
Curious if anyone’s tried those powered attic fans in a shed or garage? I always hear mixed things—some folks say they just pull conditioned air out of the building, others swear by them for keeping things dry. For me, passive venting plus making sure the airflow isn’t blocked has been the most reliable combo, but I’m not convinced there’s a one-size-fits-all answer. Climate probably plays a big role too—winters here (Ontario) are brutal for condensation.
Trusses are a blessing and a curse, right? I’ve had a few garages where I thought I was a genius for using them, then spent the next winter cursing at the condensation. Those foam baffles are a pain to retrofit, but man, they’re worth it. Powered attic fans? Tried one once—felt like it just sucked my wallet dry on the electric bill and didn’t do much else. Passive venting and keeping those air channels clear has been my go-to ever since. Ontario winters don’t mess around.
