In this section we‘ve tried to provide a step-by-step plan to restore a two-part bakehouse, a type which is very common in Belgium. With a few small alterations you can also use this plan to restore a free-standing or an indoor oven.
Once you are familiar with the different components of a bread oven, you can examine your own oven to determine exactly what needs restoring.
First look at the condition of the oven vault and floor. After all, these are essential components for baking and they are the most difficult to restore. Their condition may determine whether or not you want to proceed with the restoration.
If you do decide to restore it and you know exactly what has to be done, you can proceed.
The oven floor rests on an underlay, which generally consists of a sand layer or a sandy clay layer. In a substructure with wooden trestle you can find underneath the sand layer a layer of loam covered with lime and straw because otherwise the sand would fall through the beams. An insulation layer of lime is also provided in a stone foundation.
The oven floor has to be angled in the right way. Widthways it is always level, but lengthways there has to be a slope of 2 to 4 cm per metre, from the back of the oven to the mouth. You can check it with a marble: if it gently rolls to the front, the floor is correctly levelled. The incline of the floor facilitates ... The slope of the oven floor would result in a better combustion of the wood when heating the bread oven. The reason for this is that it allows more oxygen to reach the lower part of the oven. The combustion gases then go outside, leaving the oven through the oven vault.
When laying the firebricks or tiles, the joints must be kept narrow to stop them coming loose. The bricks are always laid on their largest side. The joints used to be filled with a clay mortar. The mortar joints used to be filled up with lime or loam mortar. The bricks are always put on their long side next to each other as close as possible and usually without mortar.
More tips on how to place a bottom layer and floor you can find in the part “Placing the oven floor” in the section “Building a bread oven”.
In case the oven floor of your oven passes underneath the oven vault, it is better to let your recently built oven floor dry for a while before you start building the oven vault.