tile flue question Design Styles, Chimneys and Finish Discuss tile flue question in the Pizza Oven Design and Installation forums; If I want to use a clay tile chimney flue, do I need to use some form of masonry to ...

[cynon767]

If I want to use a clay tile chimney flue, do I need to use some form of masonry to support it, or can I use metal studs and backerboard to create a stucco chase?

[Les]

I just sat mine into a bed of mortar then bricked around it. I did fill the gap between the flue and brick with the vermiculite/portland mix for insulation.

Les...

[cynon767]

I should be more clear. When I say support, I mean the top end. The flue would be mortared to the vent transition I have built on my arch and the front of the dome.

I guess my question is this: Is a lighter weight chase, a stuccoed box basically, enough to support the top end of the chimney flue and the chimney cap? I don't want to have to build a massive brick chimney; I am not confident in adding all that much weight to the arch, so I would have to go outward of that and build quite a large brick enclosure. Plus, the head of the design committee says she doesn't want to create the "mausoleum" look.

[Les]

Mausoleum's are cool. I think of mine as a crematory. I think you are good - gravity is on your side. The metal studs can carry a butt load of weight.

Les...

[jmhepworth]

I used the steel studs to support the flue tile, with FB blanket between the studs and the tile. It's not moving.

This picture is the best I have. I put the brick on top of the steel, but the steel also surrounds the flue tile and supports it on all four sides.

Joe

[pwcoppard]

I built a masonary flue, surrounded by metal studs and concrete board. The flue projected 1" above the top of the flue. i cut the concrete board close, then used a high temp caulk to fill the gap. I didn't use any insulation as i wanted to make sure i had a good draw. has stood up very well for more than 2 years.

[jmhepworth]

Why would insulation affect the draw?

Joe

[pwcoppard]

I thought, and I could be very wrong, that we wanted to keep the flue hot so that it would create a stronger draw. And the concrete board gets quite hot to the touch.

Maybe it doesn't matter, but i have fabulous draw, even with a large flue.

[jmhepworth]

I had the same thought, but my rationale was different. By insulating the flue, it would loose less heat and stay hotter. Mine also draws well -- 5 feet of 8 inch flue tile (6 inch inside). I suspect it simply doesn't matter. The other reason I used for putting insulation between the flue tile and the steel framing was that I wanted to hold the tile snuggly in place, but I did't want to attach anything to it.

Joe

[cynon767]

I have also heard that insulating the flue would increase draw by allowing the tile to heat up faster; but I've also read about leaving airspace around the tile to allow for expansion and movement. That's part of the question for me. Insulate, or airspace? How soild?