Like this? Can you give me a link to the half barrel system? River shack, wood siding,no insulation in the walls,some insulation in the ceiling, front addition framed in porch, rear addition cinder block on slab, extra unused chimney in the back. Maybe 24 x 50 or so overall. Current stove pipe is 5 inches I think. Might be six. I will measure when I get home.