Putting a Flue Through a Roof

[polloteriyaki]

Hi All,

I am building a cobb oven and will be adding a chimney at the front to it. I am also building a wooden pergola type structure to cover the whole oven. This means that I will need to put the flue from the oven through the roof of the pergola. So my questions very much relate to fire safety and are: How far above the roof should the flue extend? If I use a stainless steel flue how hot will it get and should it be insulated somehow going through the wooden roof -- I don't want to end up with my roof on fire!

Thanks

[Toomulla]

All vent manufacturers will have published separation recommendations for installation through roof structure. I suggest you contact them, as some are twin wall, some single, and have different requirements , same with the high temperature flashing

[RayBongo]

Hi,
I'm new to this myself and part way through my build. I plan to do the same thing - go through a pergola roof. I'm hoping to use twin wall flue for the section through the roof, and permanently fix this. Have a fixed single wall flue bottom section to the oven and have a removable section for the main length of flue.

How did you get on? Any advice from your experience?
Ray

[CapePizza]

I had built a cobb oven a few years ago. For what it's worth, and your "plan" may be different, I did not have a chimney or vent. The theory being air to feed the fire is sucked in at the lower portion of the opening, and exhausts through the upper portion of the opening. My oven worked great without any type of vent/chimney. Unfortunately the cobb material sucks up moisture and due to the moist environment where we live, my oven collapsed after 3 years. I'm now in the planning stages to build a brick wood fired oven. In case you haven't seen or read this book, I'd recommend it on building cobb ovens by Kiko Denzer . Good luck with your build.