[david cooksey]

I would build a 16' X 20' this way you do not waste materials
Gabel roof

Rim Joist: 2 X 10
Floor Joist: 2 X 8
Roof: 2 X 6
Walls: 2 X 4
1/2" dry wall
Blue Jean Insulation
Siding: Rough Tex T1-11 wood siding not OSB
3/4" CDX
2 X 8 Joist Hangers
hurricane ties

Note: If you build this structure off the ground insulate between the floor joist then cover that w/ house wrap then chicken wire.

Use House wrap on the outside walls over top of 3/8" CDX before applying the rough tex T1-11 wood siding.