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Just getting started

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  • Just getting started

    I'm building a 72x88" stand for a 42" pompeii oven, do I need a center support for the concrete harth?
    I have read someplace to add lime to the vermiculite portland insulation mixture?
    Is there any good source for firebricks in Marin-Sonoma County, the oven is being build in Sebastopol and I live in Marin.
    Any input is very much appreciated
    Thank you Rudi

  • #2
    Re: Just getting started

    It doesn't hurt to put a center support in your slab forms, because as the plywood form absorbs moisture it can sag. You want that thing rigid while for the week it cures. It's a lot of weight.

    Any masonry supply can sell you firebricks. In a busy area like Marin county there will be be multiple suppliers: shop around for the best price. For ordinary firebricks you want to go to a stone yard or building supply, the refractory dealers will most likely sell you a better (and more expensive) grade of brick than you need.

    Good luck with your project.
    My geodesic oven project: part 1, part 2


    • #3
      Re: Just getting started

      Welcome aboard Rudi,

      We're just up the road in Healdsburg (at least when we are there) and I like SBI in Windsor -- they have just about everything. They also have a Forno Bravo oven on display and are going to be installing a live demo oven this spring. Still, Windsor might be a little far.

      If you find a good Marin source let us know and we can add it to the forum. You are in a great spot for a brick oven.
      Pizza Ovens
      Outdoor Fireplaces


      • #4
        Re: Just getting started

        Thank you very much for your input, I finished the stand and harth this weekend. I used 8x8x16 bondbeams with a cont. #4 horizontal rebar at the bottom and top course. I used mortar for the blocks, added a rebar every second hole and backfilled all with concrete. I used Vermiculite instead of Perlite, since the Perlite at the Homedepot was to powdery. Mixing the vermiculite was easier than I thought. I also build a BBQ/Smoke house Base by addind a 4x4 foot section to the harthstand. This week I will be looking for firebricks. At Friedmans in Santa Rosa they have a Firebrick 4 1/2 x2 1/2 x9 . I wonder if I can use this one. They want $1.49 and the weight is about 8 Pounds. At Shamrock in San Rafael they they tried to sell the more expensive one since the lower priced one can only be used up to 1200 degrees. Any input on this available?


        • #5
          Re: Just getting started

          Hey Rudi, taht sounds like the brick I used and they are fine Low duty fire brick, I soaked all the bricks in a bucket they absorb the water rather quickley, I got about 5 in a bucket at a time, I used 165 bricks for the entire 36" oven including the floor, I used a skill saw with a masonery blade set at 1/4 " depth scored each brick and then fliped them over and hit the opposit side of the score with a brick hammer I was done in 2to 3 hours. hope this helps you.


          • #6
            Re: Just getting started

            I appreciated all the input that I received from: dmun, James and Captain.I cut all the bricks today and did a trial layout.While I was laying out the dome I've run into a problem. It's a low vault 42" dome, 18" interior height. Laying the bricks along the drawn line, I averaged appr. 3/8" outside gap on all bricks except between the 1st and 2nd row, where the bricks sit on the narrow 2 1/2" side and the 2nd row sits on the 4 1/2" side I've got a 2" gap on both sides. Am I doing something wrong or do I need to cut a 2" angle off the bottom on the 1st row? Or do I have to cut a 2" angled shim to insert? What is the best way to solve this? Also is the 3/8" gap on the other bricks acceptable?

            Thanks in advance.



            • #7
              Re: Just getting started

              The brick surfaces that face the inside of the oven should be set as close as possible to each other, you may get a gap of 1l8 to 3/8 thick that is filled with fireclay mortar. The surfaces that face the outside will have gaps that are filled with fireclay mortar that can be quite large because you are building a circular structure with linear material. You are putting in a square when a pie or a V would be more suitable. The key here is to make the fire side surfaces as close as possible.

              The first course is sometimes called a soldier course. If your gap is too biug due to the making of a perfect circle you could decrease the over all gaps by slicing a brick in half lengthwise. This filler brick should be put toward the side so that it is hard to see when someone looks into the oven from the opening.

              On top of the first course can be called the first ring. this ring of bricks generally will have the most filler mortar applied as it sets the angles for the dome. Persnally I have not been too thrilled with how this first ring is placed. The fire side of the bricks looks good but below each brick and on each side of the brick is a lot of mortar. There is not much you can do about the sides as again our bricks are not wedge shaped and thus you use the fireclay mortar.

              Here is a dry shot of the gaps you can expect on the outside of the dome, thanks to marcel


              One thing to rememeber is that the instructions are made so that the every day home owner can build a pizza oven without too much engineering and a modicum of skill.

              A professional brick layer, and yes we have a few everyday homeowners here who have uncovered a hidden skill, would do something like the folks at The Masonary Heater Association would do <giving credit where credit is du>, make the first ring on top of the soldier course a skrew course. That involves cutting your bricks at the angle that will be set up for the rest of the rings.


              The idea is to get the fire side bricks as tight as possible. Here is a shot from Paulages.


              Paul then went back inside the oven and back-filled or buttered in with mortar all the gaps that are visible.

              I hope this helped


              p.s. go into your profile and change your location. Although it is nice you really do not want to be broadcasting your actual physical address to the world.
              Last edited by jengineer; 01-18-2007, 08:30 AM. Reason: correcting bad typing


              • #8
                Re: Just getting started

                Thank you very much je.
                Your input helped. That means the so called soldiercourse sits straight on its 2 1/2" side and the next course will be angled to fit the dome curve even if one has to fill the 2" gap with mortar or cut pie shaped bricks to compensate.

                Thanks again je


                • #9
                  Re: Just getting started

                  I started angling in on course 4, Course 1 was a soilder course, then 2 and 3 sat on the flat sides. I don't think most do it that way, but anyway...

                  to your question about the angle. I think this picture shows using a lot of mortar to get the first leaning course to fit the curve of the dome. Hope this helps.

                  My Oven Thread:


                  • #10
                    Re: Just getting started

                    Thank you very much Drake, the pic is a big help. I have some other questions though, some of the bricks that I bought have some minor cracks in them, are they ok to use or should I just toss them? My other question is would it be better to cut the floor of the pizza oven round and set the soldier course on top of the insulation next to the floor and cut the soldier bricks 7" tall? or is it better to let them sit on top of the floor with the 4 1/2" height?

                    are there any thoughts on this?

                    Thanks again,



                    • #11
                      Marin Brick Source

                      bit late for this oven but McNear's in San Rafael has fire brick. I don' think they make it like they do their pavers etc, but they offered to sell me some seconds and shipped over a couple of samples. Seem a little crumbly compared to my other source (Castaic Brick in LA area). They are a trifle thinner as well 2.25 inches vs a full 2.5 in from Castaic. Other dimensions identical. Too bad they can't organize a quote as fast as they ship samples! or maybe I'll ask for 100 quotes with 100 different names.

                      Shipping fire brick to the Islands isn't cheap. Best I've done so far is a quote for about $725 for 250 bricks. I'm targeting a 36 inch Pompeii so that's probably overkill but since most of that cash is shipping, the price doesn't change much for 200-225 and I'd rather have left overs than be caught short.

                      I'd love to hear the answer re making the soldier course a soldier+skrew course as well. I'm thinking of a hearth inside the wall design so if I nip the soldier course at my dome radius, and put the hearth inside the walls, the first course appears to be only about 5.25 inches (9-2.5-1.25) vs the usual 4.5 inches many have.

                      Any input from the experienced builders?