taking a vote on chimney or not

[rwiggim]

I just finished my dome and need to make a decision as to the chimney. With the rains coming and the material I used to cover the roof of the pergola I really don't want to go up and through the roof. I have added a few pics of the oven and structure as well as a pic from Balty that shows what I am thinking would work. I have about 50" or 110cm between what would be the top of the small chimney and the rafters of the structure. I live in Portland OR where it is usually at least breezy if not downright windy and the ceiling of the structure is open on all sides as to not trap hot air. I also would rather insulate and put up metal sheeting above the oven than go through the roof. Not having used a brick oven before I just wonder if there is too much heat coming out of the chimney to be a true hazard or if it would dissapate quick enough. please chime in with a yes( I need a chimney through the roof) or no( I can be lazy and not burn down my structure.) I will put an overly sufficient spark arrester on and may revisit the longer chimney after the rains stop next year.)

Thanks so much,
darren

[camarina73]

It is definately a fire hazzard. I would go through the roof.

[Chris]

I think your pergola is likely to burn down if you don't put a chimney through it. Before that happens, the underside will probably get blackened from the soot.

When you have the oven going full-throttle, the flue gases are very hot. I will be firing up tomorrow, and will measure the temp at the chimney cap and report back.

What is it about the roof that makes you averse to a chimney?

I started out with a simple sheet metal roof that I meant to shelter the oven and the cook. The oven took up so much space underneath, and I couldn't figure out an easy way to flash in a chimney, so I just moved the shelter and put a separate roof over the oven.

Now I think I might do away with the covered shelter altogether. We've got plenty of shade trees, and we don't usually get so much rain as Portland.



Good luck!

[RTflorida]

Chalk up another vote for the chimney. I know when the fire is raiging the flames can lap the entry and up the flue a bit, so I know there is incredible heat going up the. I've measured the temp with my IR - we are talking in the 600-800 degree range when the fire is roaring along.

[nissanneill]

Darren,
I think that you would be crazy not to incorporate a chimney for the reasons expressed above.. Until I put in my chimney, I lit a few fires to cure the dome and melted all the overhead irrigation pipes and sarlon shade cloth. My oven and dimensions to the roof is pretty similar to yours, so you will get a huge amount of soot, heat staining and probably charred timber, hopefully it does't catch fire.
Put your hands up there when you have a reasonable fire in the oven rather than burn yourself with a serious fire which will be necessary for pizzas.
Surely you can manufacture a simple vent and put a couple od 8" flues through the roof and seal around it.
Check out my idea at:
http://www.fornobravo.com/forum/atta...t-flue-web.jpg

Although not finished there, it works a treat and when I build the new pergola prior to christmas, I will be putting the flue up through a polycarbonate roof.

Neill

[rwiggim]

So I guess I will be putting in a chimney. My roof is corrugated aluminum which I fear it will get uncorrugated as I trample on top of it to flash a chimney pipe. I just don't want the copious amounts of rain to puddle and wick down the pipe. Perhaps I will call in the pros and spend my time building the enclosure.

[Unofornaio]

Originally Posted by rwiggim

My roof is corrugated aluminum which I fear it will get uncorrugated as I trample on top of it to flash a chimney pipe.

putting "stickers" (2x4s, 4x4s, ect) down on the roof directly above supporting rafters and either laying down plywood or a ladder between them to hold you while you work on the roof will solve this problem.

Or you could NOT do the chimney and after a long hot fire you wouldnt have to worry about water puddiling on the roof...

[Kemo]

I vote to go thru the roof. Safety first...