Our garage originally started out as a car port, years later the original owners fully walled it in, and added a small shop on the side, but they never insulated or finished the inside. I would like to do that.
The one thing I’m getting hung up on though is the rafter insulation. Because of the way it was built up over time, we have a slightly different setup in the main garage area, as we do above the small shop, but in both cases, the rafters run all the way to the ridge beam/board. We don’t currently have soffits, the rafter tails just hang off the outer wall, and air can freely move over the wall into the garage (as could any critters so inclined to make the climb).
In looking around it seems like the most recommended method would be to leave an air gap by installing baffles under the roof sheathing, then insulate beneath that. Add soffits to the outside and a ridge vent atop the roof to promote proper ventilation. This all seems to make sense, but I’m wondering what other options might be acceptable that would avoid me having to install a ridge vent.
One thought was to add collar ties just beneath the ridge beam, to allow air from the soffits to be able to be able to reach both sides, and simply installing a few attic vents on the backside of the garage (out of sight).
Any reason that wouldn’t work? Is that even necessary? Given it is a garage, I’m really just looking to get to the point where the temperature is mild year round, things won’t melt in the summer, etc. I also don’t want to ruin my roof or cause any moisture problems. If I just simply ran baffles straight up to the ridge, and didn’t install a ridge vent, would that be a huge mistake? I’d like to keep the roof height if I can, installing collar ties will obviously drop the height, but I’d rather loose some height, than regret it later.
One contractor suggested I could just drill holes through the ridge beam to allow air to flow, but that seems a bit questionable to me. The main beam of the garage spans 20ft, and drilling a set of holes in each rafter bay doesn’t seem like a great idea. I’d be happy to be wrong though 🙂
Two images attached to hopefully make this more clear.
One other bit probably worth mentioning is we live in Southern Oregon, a pretty temperate climate. Snow is really a non-issue, maybe a light dusting 1-2 days a year.
Appreciate any advice and insights you can might have. Happy to share any additional details that would help as well.
edit: don’t know why the images uploaded upside down, sorry for anyone who gets a kink in their neck looking at them…