42" build in McPherson KS

[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]

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..

[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]

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]

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]

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 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]

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..

[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]

I found the thread I was referring to above, it was Tscarborough who talked about having a poured a landing, and it was plain mortar not homebrew.

https://community.fornobravo.com/for...098#post129098

I am hoping to have a poured landing (about 4 inches thick) with a 2-inch overhang and am wondering if I need any reinforcement like chicken wire? I am thinking I will use homebrew instead of plain mortar.

Let me know if there are any flaws with this plan.

[Gulf]

Sorry about the late reply. I want to comment on your last three posts.

How long has the locust been dead? Start the seasoning time form the first notice of it dying. I use a lot of dead fall. It starts drying as soon as the sap quits flowing.

I'm not pointing out "flaws" to your plan. I'm just relating what I did and how I use my oven. I did not use the ss heat break so I can't comment on how it would work with the way I use my entry. I just placed a flat ceramic fiber tape in the seam and continued on out with fire brick through my entry. My entry takes a lot of abuse. I drag coals out of the oven for the tuscan grill and for dirty steaks.

Chicken wire is not reinforcement. 4" thick concrete should have 3/8" tp 1/2" rebar for standard concrete. However, for a refractory, it is a different ball game on the use of reinforcement. I guess it is up to you on how you will use that small amount of valuable real estate.

[slschoming]

How long has the locust been dead? Start the seasoning time form the first notice of it dying. I use a lot of dead fall. It starts drying as soon as the sap quits flowing.

All but one branch has been dead for a year now. I have some older stuff that has fallen in my yard over the past few years that I can use up and then this tree should be ready..

I just placed a flat ceramic fiber tape in the seam and continued on out with fire brick through my entry. My entry takes a lot of abuse. I drag coals out of the oven for the tuscan grill and for dirty steaks.

Chicken wire is not reinforcement. 4" thick concrete should have 3/8" tp 1/2" rebar for standard concrete. However, for a refractory, it is a different ball game on the use of reinforcement. I guess it is up to you on how you will use that small amount of valuable real estate.

Maybe pouring the landing isn't a good idea for me after all.. I don't want to mess with figuring out how to reinforce refractory and if it isn't as durable as firebrick then I don't think it's the right choice anyway... I plan to use a tuscan grill and I imagine I will be equally rough on the landing. I was just trying to come up with an easy solution to the variations in height I have going on right now between the insulation, firebrick, house brick...I do not have a nice level area there right now. I guess I will take a grinder or cutoff wheel to try to level it out the best I can so I can extend out to the edge with firebrick.

Do you mortar the firebricks together in the landing area or leave them loose like the floor under the dome? I was hoping to have a 2 inch overhang but that obviously won't work with loose firebrick.

Thanks for your reply!

[slschoming]

Gulf pardon the terrible sketch, but here is the new plan... I will pour a small concrete ledge with a lip so that I can lay firebrick between my stainless steel heatbreak and the lip in the concrete. I can reinforce the (approx. 3" thick) concrete with rebar and still have firebrick as the landing floor.

[Gulf]

Very sorry for the late reply. I did not mortar my entry fie brick in place. However, at the heatbreak, I did switch from herringbone to a running bond. The only mortared in section is a thin strip across the opening even with the outside face brick. That is what I call the entry. My landing (or shelf) is poured concrete.It sets outside separately on corbels, is removable and has very slight slope away from the oven for drainage. My theory behind that is that in a driveing rain it will allow water to drain away from the oven. Also, water that does make it to the entry, will drain between the entry and the shelf.

I poured my corbels with the hearth slab. But, I have seen others add support for corbels and the the shelf by drilling large tapcon screws into the hearth slab.

I really think that the entry fire brick need some insulation underneath. P/Vcrete will level your enty and add some insulation imo.

[slschoming]

One year ago today I broke ground and framed out my slab... I was really hoping to be eating my first pizza today..

I made a little progress on the landing today. I leveled everything up by grinding stuff that was too high and filling in low spots with pcrete. I mortared the very front edge row of firebrick down and I have 1 firebrick length of running board (loose) between that edge and my stainless steel break. I also made a template for the outer arch.

Does the firebrick stay this bright yellow, or does the color eventually fade? I want to age the look of the fire brick edge. Are there any techniques I should try? I was thinking about dipping a sponge in some really wet home brew and stamping the face of it or something. I might test that out on a scrap of firebrick and see if that helps.