Technical Design Question, Wooden walls still need Tension band?

[Bob Rowlands]

I think a twelve sided building, 12' in diameter, would look cool. It you have a twelve rafter roof, the building is definitely going to look better with twelve flat walls. I'd forget messing with circular plates. I'd use 2x4 studs on the wall ends. Forget using 4x4s.

You can easily production cut all 24 2x4 wall plates, (15 degree angle), nail up the wall sections, and quickly erect the walls. Install a stud in the middle of each 3' long wall section that doesn't have a window, or the door, for nailing up sheet goods.

Lap the double plate as you said. Tie the top plates together with 1 foot Simpson Strong Tie metal straps running horizontally at the outside plate joints. Anchor the rafters to the plates with Strong Tie rafter brackets, 1 on each side of each rafter, oriented on the inside of the building. 1x6 t&g roofing solidly nailed to the rafters will prevent the roof from expanding.

I'd like to suggest a roof overhang would be a good idea on this building. Run the rafters past the outside plate line by a half foot to a foot, depending on exterior wall height. Buildings look good with an overhanging roof.

Will be plenty strong and straightforward to build. Easy to finish off because all surfaces are planar. Will withstand the weather fine. Plus is gonna look REAL cool!

Have fun.