42" build in McPherson KS

[slschoming]

I will be using a stainless steel break between my firebrick floor and the landing, similar to what UtahBeehiver did with his. I am wanting to "pour" my landing. Should I be doing this with homebrew, regular mortar, concrete, something else?

I think I read a comment (by david s, maybe?) on another thread about using homebrew for this, but that you should not get the mix wet enough to pour or it will crack but now I can't find that thread again. Does that sound right?

[slschoming]

Well, I didn't get as much done as I wanted on the oven this weekend, but I filled my wood storage and then some. I had to bring down a dead locust tree because my wife's tree climbing uncle was in town with his gear. It was a pretty neat process... So, in a year or so I will have plenty of seasoned locust wood. Hopefully I have an oven by then..

[Gulf]

It looks and sounds good. I have a 44". I did full scale drawings on cardboard to help me be sure. The drawings, one for the foot print and one for a side view., helped me a lot. I think that you have this, so take plenty of pics. It will help someone else down the line.

[slschoming]

It's probably just me. I'm putting in some long hours. But, the inner/outer arch drawing appears to be reversed to me. Do you have any pics of what you have done so far? Many times a dry stacked pic yeilds a "now I get it moment" for me lol. It does sound like that you may be spreading the weight around the arch to the side walls and on down to the hearth. And, the buttressing for the flat arch, should be enough. I would like to be sure how you will be getting that support for the jumbo house brick on the back side of the chimney. That weight has to be transferred back to the hearth outwardly which is undercutting the back wall of the chimney.

Not sure if this helps, I added some color coding and arrows and some more details... I don't have anything dry stacked, this sketch is the only thing that physically exists pertaining to this idea. I am going to work on this a little bit this afternoon, though.

Basically, the outer arch will be 4.5" thick above the inner arch, and 6" thick above the landing. I will have 10.5" sidewalls to support the arch and will build a chimney on top of all of it. My sidewalls will contour around the dome (sketch #2), leaving about a 3" gap so I am sure to have them far enough back to support the back portion of the arch.

[Gulf]

It's probably just me. I'm putting in some long hours. But, the inner/outer arch drawing appears to be reversed to me. Do you have any pics of what you have done so far? Many times a dry stacked pic yeilds a "now I get it moment" for me lol. It does sound like that you may be spreading the weight around the arch to the side walls and on down to the hearth. And, the buttressing for the flat arch, should be enough. I would like to be sure how you will be getting that support for the jumbo house brick on the back side of the chimney. That weight has to be transferred back to the hearth outwardly which is undercutting the back wall of the chimney.

[slschoming]

Seth,

The wedge shape that you drew may well be what you need at the bottom of the outer arch. But, the dome should be pulling inward and away from the outer arch after a couple of courses. So, after a couple or so of courses, you really shouldn't need for the brick to come to a knifes edge "to maintain a consistent 2 inch gap between the dome wall and the chimney arch wall".

Good point.

My sidewalls (from inside to out) will be one firebrick "on bed" next to one firebrick "on edge" next to a king size (2.75" wide) house brick... The whole sidewall will be about 10-11 inches wide after mortar joints. There is no reason I can't make the whole arch thicker so that I have the width of a full firebrick on the part that will overlap my inner arch and then lay a second course of 1.5" bricks on top of the rest of the arch to make it flush. I would basically be making two separate arches of full firebrick joined together by mortar and then made flush on top with a thinner second course over the portion that is NOT directly above the inner arch.

I am attaching a sketch that will hopefully illustrate what I am thinking... the top is a bad attempt at a 3D representation (without the layer to make it all flush) and the bottom sketch is a side cross section that includes the layer to make it flush.

Would that (with my 10.5" sidewalls) be sturdy enough to support a 2 foot tall chimney?

[Gulf]

Seth,

My heat break iwas more or less just a notch. Many since, have went to "what they refer to as, the L-Shape. Some were so thin that I was a little conserned. But, I haven't heard of any problems with those ovens. However, most all of them were only attaching stainless steel vents. That route does not place an extreme amount of weight on the outer arch. I went with an all masonry chimney, In doing that, I transferred most all the weight of the chimney around the entry to the hearth slab. The wedge shape that you drew may well be what you need at the bottom of the outer arch. But, the dome should be pulling inward and away from the outer arch after a couple of courses. So, after a couple or so of courses, you really shouldn't need for the brick to come to a knifes edge "to maintain a consistent 2 inch gap between the dome wall and the chimney arch wall".

All that said, I don't think that your current deign will have enough support to build an all masonry chimney.

[slschoming]

Gulf I have a question, but it requires a bit of explanation. Hopefully this all makes sense.....

I started on the sidewalls of my chimney using a brick shaped like the sketches attached below. I made the angled cut in order to maintain a consistent 2 inch gap between the dome wall and the chimney arch wall (see sketch #1) so I can stuff two layers of insulation in there when I insulate the dome. I will ultimately have 3 layers of insulation around the rest of the dome.

The portion of this brick that will be outside / above my inner arch will be 1.5 inches thick (and diminishing to nothing at the tip since I made the decision to make the angle cut). See sketch#2 (thickness is incorrect in the sketch. It is 1.5" instead of 2").

I will be transitioning to an 8x12 clay flue liner that will rest on the thickest part of the brick arch. I will wrap the clay liner in 1 inch insulation and then put house brick around it. Some of this house brick will be resting on the 1.5 inch thick section of arch, but will be tied into the whole chimney wrap that will be resting on the arch where it is a full brick thickness.

My question is, will the back part of this arch that is only 1.5 inches thick be too weak to support this?

If you look at the third sketch.. The whole brick wall surrounding the chimney is highlighted blue and the green is the small section that would be resting on the thinner part of the arch..

[slschoming]

My Duuuuude!! Looking good! Keep it up....pizzas are in your near future!! Zoo

Thanks! I feel like I am close, but I am also struggling to find the time now that my kids are back in school and I am their full time personal taxi driver after work again. I'm hoping to squeeze in another workday over the weekend and see how much I can get done on my chimney.

[slschoming]

slschoming UtahBeehiver cobblerdave Gulf This has been one of the most helpful threads for me. I really appreciate the time everyone takes to help on this forum. I'm a little behind you seth, so I'll be watching! One thing I notice is that many peoples signature gallery links go to picassa, which has been discontinued. It would be great to see these pictures again on an updated site. (looking at you Gulf )

I'm glad this thread has been helpful to you but I am going to pass all the credit on to those answering all my questions! This forum is a great community and I would have never attempted this without such great resources at my disposal. A big thanks to all!

[mintee]

slschoming UtahBeehiver cobblerdave Gulf This has been one of the most helpful threads for me. I really appreciate the time everyone takes to help on this forum. I'm a little behind you seth, so I'll be watching! One thing I notice is that many peoples signature gallery links go to picassa, which has been discontinued. It would be great to see these pictures again on an updated site. (looking at you Gulf )

[slschoming]

Thanks Gulf. I will plan for a 1/2 inch gap. I picked up a 8 x 12 OD (6.5 x 10.375 ID) flue liner and I think I will be able to make it work. I will wrap it in 1 inch thick of scrap insulation blanket and build brick around it, but I'll have cut my 4 inch brick down to 3 inches so I end up flush with the edge of my hearth.

I stopped misting the dome today. I'm hoping to find some time in the next few weeks to build my chimney / outer arch so I can start curing my oven.

[Gulf]

Seth,

I set the template for 1/2" gap(s). The rope that I used is braided and has a hollow in the middle. It will flatten out nicely into an oval without compressing too much. That works out pretty good since we are trying to make circles using rectangles. Between the inner and outer arch there will be some differences in the gap depending on where exactly the joints line up.

[slschoming]

Gulf and/or UtahBeehiver ,

Hey guys, I am getting ready to start on my outer arch / landing / chimney area. How wide of a thermal break did you leave? Gulf, I see you stuffed your corner with 1/2 inch rope and 3/4 inch rope on either side of that. Was your gap on the sides 3/4 inch or did you make it just a little bit smaller for a snug fit?

Thanks!

[slschoming]

Capped the dome today! Next up, vent/landing...