Chimney height

[Sandieego]

was wondering if anyone had an idea on how high a chimney has to be. I assume as long as it is above my head, it should be fine. I like the looks of a small brick chimney. I was thinking of something like the base of Adamk's amazing one with a cap of simple brick squares at the corners and a 2" thick cast cap. Anyone done that? I would think it would be small enough to not need any extra support.

[Sandieego]

I tried to make a new post here and hopefully, someone will answer my question above. this is my build.

I went ahead and poured concrete. My neighbor had a crew doing it the week before I started, so I went there and learned from them a few details on doing it. then tried it on my slab.
First of all, let me tell you. Mixing things up in a wheel barrow is hard, all day work. that said, it was fun, character building and a bit messy. For the smart people, like all my friends who viewed these things and figured it too much work, they would hire someone or get a mixer machine. Me, and the rest of us, do not. I let this set and a week later did the block work.

[Sandieego]

So this was my start of the build post:
So. This started as most my projects do. I did a little "research" looking at you tube videos to make a pizza oven as somehow I just don't think our oven at home is making the ones I would like to produce.
The refractory cement one with excercise ball looked simple enough and I figured that if I built deep in my backyard it would not be so noticeable and if I made a mess, it would not cause problems around the house. When I brought it up to my wife, she said, "why build something that far away and never use it. you should put it closer." Then, when I went to explain to her the details, she said, "don't tell me, just build it." (side note: I tend to ask her things when she is already busy) SO I took the opportunity and decided to build it.
I first chose a site, side of yard, doesn't see much activity, never really put anything there, out of walkways. In the process, I ripped up some plants and pulled up some wires and irrigation, put this stuff to the side.
Then, I pulled them up, prepared a base, laid my forms and poured concrete.
I am not a contractor. I once built a 8 by 12 shed with a tiki shaped roof, so I figured if I could do that, I could do this...

[Sandieego]

Now, I'm back on the sequence of the build.
This was the build a concrete structure day. I started by thinking the mixing of the mortar was going to be easier than concrete. Boy, is that wrong. That stuff is still heavy, plus a 60 pound bag of mortar does actually feel heavier than a 50 pound bag of concrete. Go figger!
I went for the basic rectangle structure. after reviewing overall size for my oven (aiming for somewhere between 36-38 at this point). I went with a 5 by 6 dimension wall.
After I placed the bricks and made a concrete lintel, I was more than surprised that the thing held up!!! I think I said before that I was not an engineer type, I am also not a mason. My walls are wavy and not even, but I figured pouring concrete down the channels and I will apply an exterior wall with the QUIKCRETE surface bonding cement to make the structure even sturdier when I am done!

[Sandieego]

So that was three weekends in. After building the wall, my wife started asking questions...
how big is this going to be? What are you going to put there? How high is it? Then, the most famous of them all, do you know what you are doing?
I figured with the hours of research I have been putting into this I was probably on a mental level of master builder. I was also gaining some serious concrete mixing skills. I think a total of 3000 pounds goes into the support form and walls (and I am not counting the water we added to mix it). I am sure there is some post or data sheet here that calculates it out for you.
Any way, I made my forms, used melamine plywood as it was the same cost as plywood and I figured would be easier to pop off, made weep holes based on some prior posts recommendations and hoped for the best.

[Sandieego]

Now on to the next weekend. I laid out my forms for a base insulating layer of perlite:concrete. I forget the ratio I used. It tended to make the perlite turn into what looked like pebbles, which stuck together pretty poorly. the one thing I will say is that I would mix perlite:concrete mix ALL DAY!!!! I did this with my 9 year old daughter, masks on for all the dust materials. we had fun.
then, i poured a supporting surround for the insulating layer of concrete, then I had the brilliant idea to pull out by center forms and allow both mixtures to cure side by side to prevent the perlite mix to spill outwards. it made the leveling of the forms very difficult to do. we tried using blocks of wood and pounding it in place, it kind of worked, but there are many areas that are not level. I wish I had a concrete vibratory tool because it would have made this look much smoother.
This was an epic weekend, doing the slab. Picture of me gives the idea of the size of this thing. Makes me think, is this too big??? Looking at my measurements, based from the FB starter book, made me think I could do a 40" oven!!!
Did I say I started hearing comments like, monstrosity or eye sore yet?

[Sandieego]

I decided to take a rest week. Actually, I had to wait for my sister to bring me down the ceramic materials from a place in LA mentioned here (McGills Warehouse, interesting sales guy). So I checked to see how my plan would work. cut out a cardboard form base of 49" circumference (because of 40 inch internal diameter plus the 9 inch firebrick surround). I am going to die if someone tells me oven size is actually the finished diameter, because then I would believe this thing is really too big!
I prepped another melamine board that will act as my interior oven build support form for the indispensible tool and help with the forming of my base layer. I had time this weekend to lay them out to get a feel if my measurements worked out and how I was feeling with the build.
One thing looking back, photos are great. especially when viewed from afar. Looks like I may get to wear I need to be; however, while doing it, I was very suspicious that I would ever complete this task.
By the way, my motto for building stuff is, don't get hurt, don't make it worse and when you need help, get it. So far, keeping to it.

[Sandieego]

Really excited at this time now, Got the ceramic boards and placed them. this was very easy. I highly recommend using it as it is so easy to cut (with mask and wear full length clothing as the stuff can be very irritating if rubbed on your skin). Had my number one helper with me on this day, my son. Must admit working with the kids on this has made this a very enjoyable project!
Techinically speaking. I added mortar clay and sand mixed 1:1 dry on top of my perlite insulating layer to provide a homogenous and smooth base for ceramic board. plus I figured this would fill in any gaps from the loose areas of perlite.
I also took this time to sand my floor for the oven with another fire brick. works like a charm. had minimal dust exposure. not sure if this posted somewhere else, but it kind of came to me, I tried it and seemed to work. smooths down the uneven matches rather nicely.

[Sandieego]

Getting late for me to keep adding, but on this weekend we finally started adding the rows. One thing I learned quickly was that the string and pencil approach does not make a good circle. I am sure there are tools that people use, but I noticed as I laid out my bricks that they did not lay in a perfect circle. so instead. I used by adjustable IT I designed to help set all the first bricks. this allowed me to make a perfect circle with the first layer! Now my oven is a little over 40" diameter, though, so it is even bigger! You can see what I mean in the last photo where the bricks do not sit perfectly along my white melamine board (evidenced in the last photo) the added advantage of this is that the plywood is not tight to the bricks and will mean taking it out will be easier. to keep the circle in place I added at least 5 bricks as i figured the 40 pounds of weight would keep it from moving, which helped. it did not move during the first layer.
I am planning on a 3/4 inch reveal on by oven to landing transition, so once I pop out the arch, I will add 3/4 inch plywood to it so I can make the outer arch off the form I use for my inner arch.

[MarkJerling]

You're making good progress. If it were me, I'd set my floor "inside" my walls so as to allow for future replacement of the floor. But, your method can work too.
To answer your original question: The higher the chimney, the better it will draw. Mine's stupidly high, but only because I had an old stainless steel flue lying around.

[Sandieego]

Thanks for the input. I was wondering why some of these ovens have some wicked tall pipes! I do not expect to go anywhere near that, maybe two rows of firebrick off the arch and then add the stainless vents with the 36" long, 8" diameter pipe.
So, the weekend after laying out the floor, I got into some serious brick work. I did the home brew because as someone else says, "I'm cheap". I mixed up 3 parts pool filter sand, 1 part mortar clay, 1 part portland cement (which reminds me, I need more of this), 1 part lime. The interesting thing is how different this stuff is to who mixes it. Must admit, it goes together nicely here in SD.
I had another helper this weekend, my 11yo daughter.
By the way, I go from morning karate (1 hour intense workout with my son) to dance activities between building, then making dinner to give my wife a break from the meals on the weekend. got to admit, makes the day pretty exciting! Needless to say, we have been eating hotdogs!!!
What's so funny is seeing everyone else's build and thinking man, this looks slow. it has to be faster. then you start it. And man it is not fast!

[Sandieego]

Holly moly! getting the arch transition is down right scary. My bricks did not match up completely to this area. also, I made a 19" opening for my 40" oven. I placed this opening where my floor circle was perfectly 19" apart. The angled arch bricks would be sitting right at the sides of this 19" gap, then, with my IT tool I measured my arch bricks for position and it looked like the arch was lining up tightly with the dome if planned with the IT. Then, something happened, maybe I adjusted my IT too soon, but the dome became about 3/4 to an inch more inside of the arch. I had to bevel my bricks a little to make it work, but I think it was turning out okay.
I kept telling myself it was probably the kid in the dome not doing a good job of quality control!
As a side note to people working with mortar for the first time, the material hardens over time! People tell you to wet bricks, others say you don't. My experience is that you do not need much. having a moist mortar soaks into the bricks and will quickly start to harden and allow you to work with it. when the bricks are too wet, the mortar stays moist and does not do as good a job at holding things together. Basically, I laid it down on the bricks, then put my brick in place. Then, i would push the mortar into the gaps 5-10 min after setting the bricks (it hardens to a clay consistency pretty quickly), then scrape the excess stuff off in 12-24 hours to get the grout lines clean (don't use a sponge because you pretty much just smear the stuff all over the place and get a hazy appearance) and finally, don't see if it is holding together until 48 hours or longer (I pulled on my second row two hours after placing them and yanked off 5 bricks in one cohesive row, tried doing that a week later and they won't budge!). Further side note, I do not have any experience with this stuff.

[Sandieego]

So I was a little nervous hitting this point hearing of the dreaded arch droop or not keeping the dome shape circle and considering my arch to dome transition was not expected, I was a little shaken. I mustered on though because I am already about 4K pounds of materials into this puppy (probably less than 1K as my fire bricks were less than 1 dollar each, thank you CL) and no one was hurt and it was yet to look like a dome. I am thinking once I get past this arch thing, it is going to be super easy! And start looking like a dome!
Please admire/inspect (in horror?? ) the brickwork (third image where one brick looks like it is about 1/4 inch off the row) and the engineering (the chipped off keystone brick I placed in the center of the arch to straighten out the next row).

[Sandieego]

I must say the Stem claw was fantastic for these upper layers. It is the tool where you bend simpson ties to keep a brick in place. It was simple to understand, cheap to construct and saved me much time. Thank you! I feared with my level of non expertise and Jedi like clumsiness, I would be hitting those sticks left and right and knocking bricks out of place often, but this helped me out. That and gaining experience with the mortar mix, that stuff forms fast!
finally finished off the arch transition with an almost perfect circle!!! not sure how that happened. these are pics facing the inside. was so much fun to see how this can look. also noticed some gaps in the mortar between bricks. I am going to fill this in the next time I start laying bricks. was thinking if anyone with experience, would you jam some cut brick edges into the gaps or just fill with mortar?
another thing I did was set up a mixing and cutting station. helped me keep the area clean and my mind organized.

[Sandieego]

Here are close ups from the side of the arch to dome transition to see how my build did not match up perfectly.
I am not sure how this may turn out now, but then I looked at the FB image galleries of old pizza ovens. they had large gaps and stones, so I figure I'm okay for at least my life time!
I am looking forward to the next weekend I get to start connecting the rings to finish the dome and excited how my final plug will look!
Just an FYI, as I went up the dome, I found as the ring of brick progresses to the right from the center towards the arch the bricks need to beveled on the left side to decrease the v gap between bricks. then as the bricks progress from center to left towards the arch they need to be angled towards the right.
not sure how the next rings will go, but I will likely start making my bricks shorter in length, like 3 inches. so far after ring 8, I am still close to 4 to 3.75 inches per brick for the 8th row. Having FUN!