For outdoor installations, you can use either a Simpson double-wall sectional chimney system, or terra cotta chimney pieces. For indoor sections, you should use a Simpson triple wall, grease-sealed sectional chimney system approved for internal oven use. Check with you local building codes.
The following table outlines the internal diameter of the chimney for the different oven sizes:
You are ready for the next step: building your Oven insulation.
Or, go to the Table of Contents for an overview of what is coming up.