Building a platform - thoughts.

[Aaron Harris]

Hello!

I'm looking at building a 30' yurt. Before I commit to my footings, here's the situation. I'm trying to minimize the number of footers I need to dig and pour/slipform: I'm down to 12 in my design.

It's rocky granite mountainside (beech) forest, though with a reasonable amount of loamy topsoil, 4' frost line. I figure I'll do some slipform stone and cement/mortar to speed the footers up.

I checked out the maximum permissible spans for various weights and lumber dimensions, and since 15' was too far, I went with an octagon instead of a hexagon. (It would have been nice to get away with 7 piers)

I'm also planning on snow load.

30' yurt. 4 12' sistered 2x12s for perimeter beams, 2x8s or 2x6s for the joists spanning up to 9'. I'm not in love with the joist layout, but I am pretty sold on the octagon perimeter and 4 center piers.

Are there any obvious problems with my design in the attached images?

Thoughts?