- Demolish without destroying
- Make something new with old
- Isolate to heat well
- First batch!
- Demolish the vault of the oven
- To form the sole
- Delineate the departure of the cordon
- The most beautiful bricks to dress the mouth
- Lay a short-lived mold
- Mount the bricks and standardize
- Realize an insulating protection
- Install frame and door
Against the house that had just been bought by Gérald Nardin, there was an old bread oven. The first batches were right of the vault degraded by years of abandonment. Taking his courage with both hands, our reader undertook his complete reconstruction.
Duration: 3 to 4 weekends
Cost: 100 to 350 euros according to possibilities of recovery
Material: concrete mixer, grinder, mason's tools
See the plan of this realization (in pdf): Restore a bread oven: the plan
The use of bread ovens until the revolution of 1789 gave rise to taxes levied by the lords. When they became family or collective, they contributed to village life and had a social function. After the first world war, their utility became punctual. Only survivors of renovations and modernizations survive. To restore them is more pleasure than necessity. But their return to service allows to reconnect with forgotten gestures that have quality value.
Demolish without destroying
Each ignition of the furnace caused further degradation and several attempts to restore failed. The bad weather and the abandonment had undermined the solidity of the construction. The decision was made: demolish and redo the same!
■ Demolition also means observation: it is an opportunity to identify the method of construction because the old procedures are not often used anymore. To acquire even more of this knowledge, also address the witnesses of this other age, eager to share advice and recommendations.
■ When it comes to catering, the most efficient, and also the most economical, is to work with recycled materials. If the condition of the reliefs of the old oven does not allow it, remains the possibility to look for materials nearby, even if all these findings sometimes require work of readjustment or cleaning before use, as here. The bricks of an old fireplace, hulled for the occasion, have found a new life. Unearthed by research, flat molasses (soft stones, limestone and clay from southeastern France) will serve as sole. Clinker and sand are traded on a surrounding road site.
Make something new with old
On the floor of the oven, fortunately preserved, an area of 130 cm in diameter is drawn. It is a sufficient surface to bake four to five loaves in a batch. The sole, consisting of very closely laid, dry molasses, without grouting, rests on a bed of clinker 5 cm thick, known for its qualities of strength and fire resistance. The presence of a slight slope towards the door facilitates the evacuation of embers.
■ The semi-circular inlet of the oven, called "mouth", is delimited by a volume template of the future door. This consists of two chipboard plates, connected by a curved isorel strip. The installation of the template allows to delimit the departure of the crown serving as a sole for the construction. The first three rows of bricks are mounted flat with refractory cement (Mercier, Weber & Broutin, Lafarge...) added with fine sand, like all the rest of the oven. The curved cladding of the opening is realized simultaneously with the construction of the dome.
■ The principle of mold construction is to smooth a wet sand form, on which the dome is built. Beforehand, a polyane film is spread on the bottom to protect the sole. The desired shape is given to sand by trowel and stainless steel smoothing. The bricks of the dome are then mounted, inclined in "scales", making sure that the inner edges are well joined. At the top, the keystone closes the dome and guarantees its holding.
■ Its role is to absorb all the forces and pressures due to arch construction. The equivalent of a truncated cone at its base is formed with half-bricks. It is filled with well-packed mortar and the top is thus carefully grouted. The entire outer face of the oven is trimmed to the mortar and the facing bricks of the door connected to the surface of the dome by a cement bead.
Isolate to heat well
After drying, a layer of 3 cm of plaster covers the whole. Inertia is reinforced by 30 cm of clinker and earth. Three days of waiting are necessary before removing the template and emptying the sand with the shovel. The final drying will last from six to ten weeks, but the door can be laid. Made in steel, as here, recovered or unearthed in a flea market, protect it with a paint "high temperature" (Véraline: black smoke, Julien...). The frame is sealed in the opening always to the refractory mortar.
No need to consider immediate use of the oven. It must be spared, starting with a few small outbreaks that will have the advantage of completing the drying gently. So will he be ready for his first cooking! Vines, fagots and dry branches are the heating material. However, do not use treated wood that can be toxic or resinous releasing odors and unpleasant substances.
■ Fumes escape through the top of the door, while cold air entering the bottom fuels the fire. The correct temperature (about 300° C) is reached when the vault is white. Verification: put on the sole a newspaper rolled into a ball, it must ignite spontaneously. Or throw in some flour: it must burn without burning. Then remove embers and ashes. Bake the loaves with a long wooden shovel and close the door. The cooking time is proportional to the weight of the loaves, watch it!
■ For gourmands: Meats can also be baked and as it stays warm for several hours, enjoy the last calories stored to cook pies and cakes!
Demolish the vault of the oven
Under the effects of water and frost, the oven vault disintegrates and collapses. Its demolition is needed without hope of recovery, but the location is exploitable because the floor is in good condition.
To form the sole
Five 6 to 7 cm thick stones are re-cut with a saw to make them closely joined. They are laid "dry", without joints, on a bed of clinker very compact, to form the sole (or area).
Delineate the departure of the cordon
Delimited by the position of the future door, the start of the cord (or crown) of the dome consists of three rows of bricks mounted in a circle with refractory cement (melted) and sieved sand.
The most beautiful bricks to dress the mouth
The mouth (or mouth), represented here by its size, essential element of the oven, will be dressed as and when the rise of the dome. Book him your most beautiful bricks.
Lay a short-lived mold
Lay a polyane film to protect the sole. A dome "solid", wet sand and carefully packed, about 0.6 m high, represents the volume of the oven and will serve as ephemeral mold.
Mount the bricks and standardize
Mount the bricks by leaning on the inclination of the mold to form a circle concluded at the top by a keystone. Unify it by carefully masking the edge of the opening.
Realize an insulating protection
Make an insulating protective cap: cover the dome with a large layer of plaster. Fill in with a good thickness of clinker and earth. Three days later, remove the template and sand.
Install frame and door
Let it dry for six to ten weeks. Take advantage of this break to install the frame and the door. Start with small outbreaks that will complete drying before considering cooking.