Hello! New to this Forum as well never really smoked anything YET! I have a 36" x 36" slab poured, with an indirect fired heat/smoke source. I used a 20 lb LP tank on it's side then fed through a 3" steel pipe to the rear center of the slab. Wife is on me to get this built,.............ain't that cool? Anyway, I have my design in my head, but was wondering if there is any "mathematical" approach to sizing the venting. If I understand the process you NEED to vent to allow smoke to enter but to also allow moisture to leave. A vent pipe may invite critters/unfriendlies, so I was considering a grilles or vent ports with slide controls. The size of the house is 36' x 36" with proposed 5' 6" high walls,.............wood construction. Also anything else I should consider? Would love to hear those; "If I had to rebuild I would,..............". Thank you in advance for any/all ideas advice!