Tips for using local timber when building a post-and-beam roof

My experiance with large natural timbers was a bit diferent from your approach regarding the preservation. I found the process of pre-treating every massive squared post and curved log to be incredibly labor-intensive, and I decided against it. I used locally milled Douglas fir for the main vertical supports and simply sealed the entire exterior structure with a heavy deck stain after the build was complete. My biggest concern was the ground moisture transferring into those heavy pieces, so I spent more time figuring out the foundation setup. I placed the primary posts on reinforced concrete piers spaced about eight feet apart from each other. The connection point between the log and the concrete was crucial for me. I opted for heavy steel through-bolts instead of just wooden pegs, expecially where the beams rested on the piers. It gave me a much more predictable and robust structural anchor against shifting earth. The fit for the smaller rafters was good, but having that reliable connection at the base made me much more confident in the long-term stability of the roof load. It made a huge difference in how the whole thing felt when I walked under the beams.

I’ve been watching these conversations and I'm still a little confused about how the weight of all that lumber actually sits when the ground isn't perfect. My project was smaller, more like a backyard lean-to, but even then I wondered about differential settlement. Using the concrete piers you mentioned, it seems like the main issue isn't just the wood itself, but how much localized pressure those heavy beams put down. If the soil shifts even a little, how much does that affect the connection points? I relly don't know if standard expansion joints are enough when you are supporting such large timbers.

When I was working on my own frame, the biggest risk I saw wasn't settling, but the massive timbers shifting sideways. If you don't stabilize the overall frame, even perfect foundations won't save you. I used custom steel gussets at every corner where the main beams met to stop the structure from racking. It felt like overkill, but after a couple of years, I coud still see the slight give when I pushed on the corners. The gussets made the difference in how rigid the entire structure felt over time.

I used a different method for the connection between the main beams and the vertical posts. Instead of just bolting the ends together, I cut a deep notch into the tops of the posts and slid the beam right into it. This way, the load sits on the wood itself, not just the metal connection. It feels way more solid than relying on a single bolt for everything. Those steel gussets you talked about are smart, too, because once the roof is on, the sideways pressure is definitely there.