Build wood oven yourself - Free construction manual
- Construction manual for the wood oven
- combustion chamber
- intermediate plate
- Building instructions for the door
- The roof
Pizza, bread and roast from a wood oven - that's where gourmets get their hearts beating. This unique combination of natural materials and the traditional way of firing gives the prepared food its unique flavor. To achieve this, an extremely massive furnace is necessary. Read in this text how to get to your own wood or stone oven.
Not made of wood but of stone
A wood oven is not a wooden oven, quite the contrary. Its name derives from its kind of firing: these massive stoves are fueled with wood. However, the wood oven is built exclusively with refractory materials. That is why this stove is also called a "stone oven".
A stone oven is a real, small structure that can not be moved after construction. But it spreads a particularly pleasant atmosphere with its crackling fire, its pleasant scents and its rustic charisma. Properly built, it is also weatherproof. A stone oven is therefore as a garden object an ideal alternative or supplement to the barbecue area.
Construction manual for the wood oven
A stone oven is a brick construction of approx. 1.50 meters high. A building permit is not required for him. In tenements but the landlord should be asked for permission before such a fireplace is built. In addition, a lot of manual skill is needed.
If this is missing, a lot of time has to be planned. In addition, since setting times and drying times of concrete, plaster and mortar must be considered, the construction of the stone oven is quite tedious. All in all, you have to expect between 3 and 4 weeks until the first bread can be pushed into the firebox.
The construction phases are:
- top, roof
Well planned is half built
A stone oven is a permanent installation . He is also a semi-open hearth, which poses a potential fire hazard. He also emits smoke. The site should take this into account. He must be positioned so that he is easily accessible, but the house neither endangered nor polluted. If this is difficult to implement due to the size of the garden, a correspondingly long smoke pipe should be used. Thus, the exiting smoke can not pollute the facade.
On a firm ground
A finished wood oven can quickly reach a weight of 1 - 2 tons. That's why a very solid foundation has to be built for the foundation.
For the foundation is needed:
- 4 small piles
- 4 boards, 15 mm thick, 2 meters long, 20 cm wide
- approx. 2 m³ of concrete gravel
- about 10 bags of cement
- flat shovel
- Stirrer or blender
- Bitumen membranes as a moisture barrier
- 2 pieces of structural steel mat 1.40 mx 1.40 m
- 30 - 40 firebricks
With the ruler and the cord a straight square of 1.50 m is staked out. Then the base is excavated with the spade to a depth of approx. 20 cm . The soil is covered with a thin layer of gravel. Above the turf, the floor formwork is made with the boards. The moisture barrier is now designed so that it reaches to the upper edge of the foundation formwork. The webs are designed with 30 - 50% overlap .
Now the concrete is mixed in the ratio 1: 4 . When about 10 cm of concrete have been introduced, the first reinforcing mat is inserted. The formwork continues to be filled until the concrete has reached about 10 cm below the upper edge of the formwork. Then the second reinforcing mat is inserted. The formwork is completely filled and pulled off just above the upper edge.
Once started concreting work should not be interrupted . The concrete must not harden in layers, but must remain homogeneous.
For peaty or loamy surfaces, however, the foundation must be excavated much deeper. To achieve freedom from frost, 80 cm depth is required. This foundation needs a correspondingly larger amount of concrete. At least at this size, a rented mixing machine is strongly recommended in this construction manual.
Instead of gravel and cement, one can also use ready-mixed concrete as bagged goods. This is more comfortable, but also much more expensive. The gravel-cement solution costs 20 cm flat foundations about 100 euros. For bagged goods you have to count on this amount with four times the sum.
After concreting, the foundation is covered and allowed to cure for 14 days . In hot and dry weather, the foundation is watered 2 to 3 times a day .
The base is also the hearth at a wood oven. The oven door will be at about chest height, so the fire must be placed underneath to heat the oven. For everything that generates heat or stores heat, a three-shell construction makes sense. This reduces the need for fuel . In addition, the outer wall of the wood oven does not heat up so much. This makes the great stove much more harmless.
The three bowls consist of:
- combustion chamber
- outer shell
In the inner room, the fire is fueled. He must be surrounded by refractory bricks . Hollow bricks that are walled up with refractory mortar are reasonably well suited for this purpose. They already provide a good insulating effect, so that the insulating layer around them can be thinner.
However, perforated bricks are quite fragile. Therefore, fireclay bricks are ideal for the construction of a wood oven. They guarantee maximum heat resistance. However, they are a bit expensive. A chamotte stone in the normal format of 24 x 12 x 12 cm costs about 3.50 euros. For the combustion chamber, however, only a few stones are needed.
The size of the combustion chamber depends on your personal taste:
With a foundation area of 1.50 mx 1.50 m, the distance to the edge is about 12 cm (or one brick width). So you have a usable building area of about 1.20 mx 1.20 m .
Now you count backwards:
A brick width as outer shell plus 10 cm insulation layer plus 1 brick width fireclay results in a maximum combustion chamber of 0.9 mx 0.9 m . That's exactly three and a half stone lengths per side and 12 stones per layer.
At 50 cm height or 4 layers you get to about 30 - 40 chamotte stones, which are needed to build the combustion chamber. At the front you leave an opening . Traditionally, this is designed in a wood oven as a round shape . However, if you refrain from using the fancy bricks of the stove and are satisfied with a plaster, the combustion chamber can be enlarged accordingly.
Of course no styrofoam or wood may be used for insulation . Even traditional roof-felting is not optimal for this purpose. The industry offers special "chimney wool" for this purpose. These ceramic fibers can withstand up to 1400 ° C. Please wear respiratory protection during processing!
The highly effective insulating wool keeps the heat where it belongs: in the wood- burning oven. Nevertheless, clinker bricks are ideal for the outer skin. Not only are they fireproof, they also give the brick oven the right look. It is bricked with red bricks.
Tip: Used, old bricks give the wood oven a very rustic look.
At the back wall of the combustion chamber, a 10 x 10 cm hole is left in the uppermost layer. There comes the withdrawal later. The masonry base is allowed to cure for about 1 week.
The intermediate plate is necessary so that no smoke can penetrate into the oven. Finally, you build a stone oven and no smokehouse. The intermediate plate is concreted. An auxiliary formwork is built for this purpose: A board from a formwork panel is cut to abut the inner wall of the combustion chamber. The board is held in place with two crossbeams and four supports.
Then, with four boards 20 cm wide, a 10 cm high formwork is attached to the outer wall. Although formwork is traditionally nailed, we recommend fixing the boards with screws and dowels. This prevents you from breaking the bricks that have just been bricked.
The resulting cavity is filled with concrete. Here, of course, refractory concrete is mandatory. A bag of "oven concrete" of 25 kg costs about 46 euros. Again, with two pieces of steel mesh for the necessary stability of the intermediate plate is taken care of.
Tip: Lay a layer of insulating mat along the formwork from the inside. These can be plastered later. This prevents the formation of a thermal bridge.
The baking chamber is also constructed with three shells . It is built exactly like the combustion chamber, except that it does not need a trigger. The bottom of the oven is laid out on a large chamotte plate . So you get the real stone floor for the pizza from the wood oven. The whole baking chamber has also a height of approx. 50 cm . An insulating layer prevents the oven from cooling down too quickly.
The clinkered outer layer provides the rustic look and the stability of the structure. The opening for the oven door should be kept as small as possible. It is about 50% lower than the baking chamber and 20 cm narrower on both sides than the outer wall. As a layman one should be with a rectangular opening . The simpler is the construction of the oven door. Courageous and experienced DIY enthusiasts can of course also dare to a classic arch . This gives the wood oven of course a very traditional look.
Building instructions for the door
The door is particularly important in a wood oven. She must close the oven tight, but may not turn too hot. For DIYers, of course, making a traditional, cast-iron door is not very practical. The solution is as ingenious as it is simple: A piece of dense insulation felt is ideal for building an oven door.
The piece is cut to the millimeter with the help of a template made of cardboard. Then it is plastered on both sides with stove plaster and provided with two handles - done. The door looks good and is light as a feather. However, it should always be treated carefully so that the brittle plaster does not break off.
The heat from the combustion chamber must first work through the intermediate plate, then through the baking chamber and finally over the insulation. This has the consequence that only a little heat arrives above the baking chamber. Here cheaper, conventional concrete can be used as end plate. The temperatures of the wood-burning oven have decayed so much at the top that even a wooden roof is possible.
For this one needs:
- 2 formwork panels
- steel angle
- concrete anchors
- Bitumen Brick
- wood screws
- Bitumen nails
The board is cut into three equal, flat, isosceles triangles. They form the gables plus a stiffener in the middle. With an area of 90 x 90 cm the ceiling slab is a basic length of 80 cm and a height of 60 cm a suitable measure. There are no limits to the imagination here. The gable triangles are each provided with three angles.
The angles are attached to the inside and should not protrude. Then the triangles with the angles and the concrete dowels are firmly connected to the cover plate. The triangles are switched to the one on the thighs. Then the bitumen bricks are nailed from bottom to top and overlapping on the roof - done.
It is recommended to use a specially developed smoke tube for the wood oven. It has the necessary material thickness and other properties optimized for this purpose. The flue pipes are sold in a set. A construction manual is always enclosed. The set also includes all necessary components for connection.
It may sound strange, but many wood-fired farmer's insulate the plate between the combustion chamber and the baking chamber. This requires more energy to get the oven to the desired temperature. However, the heat then keeps in the oven much longer . For a successful baking experience, a constant temperature in the oven is very important.
If children are staying near the wood oven, the exhaust pipe should be insulated. It can get very hot. Insulation not only excludes the risk of injury. The trigger also "pulls" better, because the smoke in the tube does not cool down so quickly.