Chimney height

[OvenBuilderBC]

I'm thinking of building a Pompeii oven inside our kitchen. This means the length of the chimney would be about 20' to go up past the second floor and out the roof. Is there any problem with a chimney this long? Will the oven still draft OK ?

Alternately I could angle the chimney about 30 degrees and then it would only be about 12' long. Is it ok to angle the chimney?

Any suggestions are appreciated.

Thanks

[dmun]

This means the length of the chimney would be about 20' to go up past the second floor and out the roof. Is there any problem with a chimney this long? Will the oven still draft OK ?

A twenty foot chimney will have GREAT draft. You'll need it because you don't want smoke in your house. You'll also need an air intake if your house is pretty airtight, as most modern ones are. You'll be talking to the building inspector on an in-house installation: He'll tell you exactly what to do. Your oven will have to meet code for masonry fireplaces, which is a little involved.

Alternately I could angle the chimney about 30 degrees and then it would only be about 12' long. Is it ok to angle the chimney?

Yes, code allows two thirty degree bends. You can't just stick it out a wall, though. Your chimney needs to be two feet above anything within ten feet.

[Neil2]

"I'm thinking of building a Pompeii oven inside our kitchen. "

Why ?

These things can generate a lot of smoke and do generate a lot of heat when you are firing and cooking. You won't be able to use it in your kitchen for most of the summer. Build it outside.

[fbarley]

Actually, indoor installation. We're just finishing framing on a new residence, and I want to install the flue for an oven which will be in the basement of a two story house. This chimney will be closer to 30'. I'm glad to hear there is a positive (great draft), as the flue will equal the cost of the oven. Three questions:
1. Is there a minimum height the chimney on a Casa 90 must go vertically before bending back to go up the chimney chase? I would like the oven floor to be about 48" above the floor, and although I haven't measured it yet, I'm concerned about having enough height to run a 30 degree leg back through the wall.
2. As this is conditioned space, I don't want the great draft unless I'm burning. Is there any reason not to put a damper in the initial chimney section?
3. If I were constructing a partition enclosure similar the Healsburg photo in the Forno Bravo installation write-up, would I fill it entirely with vermiculite? Would I enclose the flue in vermiculite?
Thanks!

[dmun]

1. Is there a minimum height the chimney on a Casa 90 must go vertically before bending back to go up the chimney chase? I would like the oven floor to be about 48" above the floor, and although I haven't measured it yet, I'm concerned about having enough height to run a 30 degree leg back through the wall.

No. You can start your flue on the thirty degree angle. If you are using an insulated flue system, this may take some engineering to get your base plate on an angle.

2. As this is conditioned space, I don't want the great draft unless I'm burning. Is there any reason not to put a damper in the initial chimney section?

You can do that if code allows it. I don't recall if I've ever seen a duravent or equivalent with a damper in it. Besides, standard stovepipe dampers only close off 80 per cent, to prevent you from CO poisoning. You might be better off with doors in the front of oven to seal off the flue. Those could be airtight without danger.

3. If I were constructing a partition enclosure similar the Healsburg photo in the Forno Bravo installation write-up, would I fill it entirely with vermiculite? Would I enclose the flue in vermiculite?

You can fill any enclosure with loose vermiculite. It can go around the flue without problems.

Have you thought about intake air, in a sealed room?

[david s]

I hope your flue has a decent volume under it to gather the smoke before it enters the flue pipe. Many ovens don't and they're notoriously smokey at start up.