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How to build your own DIY stone oven.

Germany isn't precisely Mediterranean. Especially Saxony-Anhalt isn't. A state that has "Wir stehen früher auf (we get up earlier). I am not even sure whether this slogan actually scares more people off than it attracts. Over the last two months I made a major effort to make my home state a bit more Mediterranean.

A friend told me that he had just build a DIY stone oven according to an internet manual. I asked him where to look for it and he told me the guy who put it only calls himself "heris hibi".So on Google I went and I actually found the page he was talking about. The first thing I found out is that the guy actually doesn't call himself "Heris Himbi" but that he invented a raspberry juice called "Heris Himbi". However, the whole oven outline looked very convincing to me, except for a few details I am going to mention later on. This is how it is done:

  1. At First you have to cast a concrete base measuring ca. 100 cm by 100 cm. The best way to do this is to dig a whole which is approximately 15 cm deep and put in square wooden boarding into which you can cast the concrete. To safe concrete you can throw building rubble into the concrete to gain some volume. Make sure the concrete is reasonably firm before you move on to step 2.

  2. Technically speaking you could build the stone oven directly on the base but that would mean much hassle getting things in and out. So you need to built a frame structure on which to put the whole thing. My recommendation here would be breeze block. The whole thing should be about 90 cm high, 90 cm by 90 cm and the breeze block itself should be 10 cm thick. On which to put another concrete surface. Underneath this construction you will have plenty of space to store your firewood. The original idea – differing from the heris-himbi.de suggestion was to cast the whole thing separately and lift it on top. Calculating the weight, I decided to stick with the original. But if you know four really strong men, you could actually go for it.

    1. Cover the middle of your breeze block construction using a wooden board under which you must put stilts to stabilise the frame.

    2. Furthermore you need to build a wooden frame around breeze block. Cast the concrete in there and hope your wooden board will carry the weight. Don't forget to put in some iron grating.

    3. Let it dry.

      Breeze block construction with stilts on the inside.

      Concrete surface on which to put the fireclay bricks.

  3. For the next two steps you need to get the more expensive and harder-to-get-hold-of stuff. Fireproof concrete and fireclay, which you might find in your local DIY-shop but at horrendously ridiculous prices. So my suggestion would be to contact a local stove fitter whether he can supply you with some discount materials.
    Put the fire clay bricks on the concrete surface. You don't need to fill the grooves. Just put them as closely together as possible.

  4. The next bit proved to be a bit tricky. Building the scuttle needs some creative. As suggested in the original German description, a stencil made from breeze block comes in handy. In order to stabilise the grooves between the bricks, I put tiny pieces of wood in between until I filled them with concrete. This might be a proper builder's nightmare but it did the trick for me. One thing you should keep in mind while building the arc is to cut 2 or three stones on top in half to make some room for the chimney.

    Building the arc using a breeze block stencil and pieces of wood.

  5. The next step, at first, seems to be a bit bizarre: Pile up large amounts of damp sand which you form into a nice and round hump which should have the form your pizza oven should have on the inside. Once you have finished that, you will need at least four sacks of fireproof concrete, Use one or two sacks of concrete to cover the sand with a thick layer of concrete. Don't forget, to leave some space for the chimney. Simulate a chimney, using styrofoam around which you can form a chimney from fireproof concrete. In order to stabilise the whole structure, put iron grating on top (you will have to bend it) your "dome" and cover it with another thick layer of concrete. All in all, 15-20 cm of concrete should suffice to allow you to bake bread as well as pizza. Don't forget to keep some fireproof concrete for the door. To make a door, use a styrofoam stencil, taken from your oven cavity's door's arc. And fill it with fireproof concrete, again, put an iron grating in to stabilise it and press one or two handles in the wet concrete.

    Covering the iron grating on to of the first layer of fireproof concrete. Don't forget the chimney!

  6. Once all this is dry, you can get the sand out of the cavity. If you have done everything as described above, the cavity should support itself. Now you can start building the outer brick-walls, which should be as high as the hump. The room between the outer wall and your dome should be filled with mineral wool. Try to use the one with a metal outer surface.

    The first test after building the walls and the brick chimney. The sand is still in the cavity.

  7. The next and last step differs from the original description. As I didn't like the wooden roofing, since it reminded me too much of your average fairy tale forest, I decided to go for a more subtle option: Covering this again with (normal) concrete and putting stones in the concrete, painting it all white.
    fertig

  8. Let the concrete dry for a few days. After a week or more, start making little fires in order to let it dry completely. After another week, you can try making your first stone oven pizza.

    The first pizza.

 

The thing really works and is such a cool thing to have for every garden party. Just put all the ingredients and the dough on a table and communication will evolve naturally, even between people who don't know each other, as soon as you have to share the same ingredients to prepare your pizza.

 

Original images used in the German description:

The whole thingthe scuttlethe cavity
the door

 

2008-07-11 16:10:43