Although it is already 4 years old, I would be interested in your garage offer. After more than 170 posts, you still are not allowed to send a PM here.
After more than 170 posts you still can't send a PM here
Wow. I just wanted to send you a test conversation, my latest understanding was that 150 (for sender and receiver) would be enough. It's not in my outbox, and I suspect you haven't received it either :-(
If you have a properly seasoned wood quality, there are no problems. You won't be sealing the garage like the house. Take a look at old barns in high altitude areas - they also last "forever". If you plaster the whole thing, you have to expect some cracking in the plaster at first. If you use the exterior wall of the house, you save yourself a lot of material.