The loft is just 10' wide, but the rafters are 2x10s, to get enough depth for the required insulation (R-30). They're held at the peak by plywood 1/2" gussets, glued and nailed (lots of nails).
Plywood is on the lower (south) side of the cabin. The clerestorey wall is up, and the rafters on the high (north) side are on. The ceiling in the living and dining room area is 15 feet (~4 m).
You can see a gap in the rafter spacing behind me. This is where the (yet to be built) loft will be.