Tin Foil

[TwinBay]

What is the best stuff to use to prevent the smoke within my concrete arch from seeping up around the pans?
Hard time finding insulating material.
My default for now has been Tinfoil ???

Thanks in advance.

[PerryW]

maybe to need to extend your smokestack. Sounds like you're not getting enough draft. Mine sucks air in, it there's a gap.

They actually make Arch Gasket which comes in a roll. You lay it down on the rails and set the pans on top of it.