The project
| The budget
| The Plan
| Construction
| Construction critics
| Conclusion
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Almost nothing. I actually had no wood to buy and already had the various tools needed for the building.
A shot of 3d modelling helps to get a better overview of the different steps to be performed.
The wooden base
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Insulation layer : straw and clay
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Refractory layer : clay and straw
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Fire contact layer : sand and clay
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External view of the building
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Various layers seen in section
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The support is made in a way to ensure a maximal rigidity.
After the shape cutting with the jigsaw (picture is missing) the base exceeds 40 pounds anyway ...(who was talking about overload?).
Then we just have to hit a few nails to ensure a better grip of the insulation layer. The nails have to jut out the wood around 1 inch.
Insulation layer.
Seconde layer, the clay-straw mixture can't be handle with the tools. I had to mix it with my own two hands.
Layer spreading and smoothing with the trowel.
Third layer which will ultimately be the oven hearth. Thus we have to take care of the finishing and care about compacting the stuff as much as possible.
I used a mixture just slightly dampend, I made a couple of tests to fix to perfect compromize to get a mixture which does not crumble once dry but can still be worked properly.
As soon as the intermediate layers are dry, we can go ahead with the dome shape. First cut a template out of plywood, we can see in the background of the picture.
And then just play sandpies with your bucket and some damp sand. I used some plastic film to avoid the damp in the futur hearth from the water contained into the sand.
This step is definitely important because the quality of the futur vault relies on it.
Implementation of the heating layer on top of the sand dome. Sand mixture and principle as used for the third layer (hearth)
Intermediate refractory layer. Same mixture as the second layer. The straw should be really scarce in order to provide a kind reinforcement rod as in the concrete.
Insultation layer and start of sand removal. We can notice that the top layer is not completely dry, obviously I couldn't wait hastening things a bit...
but this is not really a problem if the intermediate layer are properly dry, which was the case.
Once the sand removed, the hard step is to let the whole stuff dry up properly.
For instance I used a HP server fan and a laptop power supply which worked just fine ;)
Here we start to see a bit of how the building is gonna look like at the end. Here we're a just missing the rendering layer.
100% natural building. Excepting a few nails the materials employed are nothing more than clay, straw, sand and wood.
Heating length. A 2h heating is more than enough to make 2 consecutive batches of bread.
Low wood consumption. from 6 to 8 kilos of wood are enough.
Mobility. The rolling base under the oven allow the usage in various places but also avoid sealing a place up just for your oven.
Food baking. The heating is pretty smooth and homogeneous, the underside of the bread or pizza is not burned. Until now, that's this small oven which gave me the most awesome batches of bread.
External rendering layer. During drying phase the clay rendering took a lot of cracks I didn't fill up properly. These cracks had then acted as many small air intakes through the insulation layer. The heat coming out as well as the oxygen supply caused the slow combustion of the straw/clay layer. After a couple of months the entire load of straw had burned to ashes ... I will have now to clean up this mess and build a new insulation layer up again, unsing a bit more clay in the mix and filling more carefully the cracks of the rendering layer.
Baking surface a bit small. Even if sufficient for break baking, it's almost impossible to put more then one pizza at a time. This starts to be tiny if your audience is exceeding 8 people.