Insulated Vertical Clone Build Question

[Deanr]

I am planning an insulated vertical clone build similar to a backwoods or Humphreys.
I have done a fair amount of research and one thing I am not clear on...
The smoke leaves the firebox and travels along the outer walls of the smoking chamber to the small opening at the top of the walls in the smoking chamber. But isn't that area filled with insulation?

I would appreciate any insight.

 

[Shagdog]

You build, essentially, 3 walls. The outer wall, then insulation, then the inner wall, then a gap, then the third wall that is the smoke channel. Its open on the ends (in the fire box and at the top of the cook chamber) Its why those reverse flow cabinets look so much bigger on the outside....

 

[Untraceable]

there is false wall that it travels up.

 

[Deanr]

Thanks for the reply. That makes sense.