Old architectural style meets sustainable technology: On the school farm in Recklinghausen, a house is being built out of wood and clay, but with a photovoltaic system and district heating from our own production.
The prices for timber have exploded, and now of all times the school farm in Berghausen is planning to build a new half-timbered house. Other clients would now have to increase their credit, the large volunteer team around head Berthold Kalverkamp remains calm: “Fortunately, a sponsor gave us a quarter of a hectare of commercial forest in Flaesheim some time ago.”
The large spruce trees form the basis for the multifunctional house, which is to be built entirely in-house within a year. “The bark beetle was already on the trees, but we can still use the wood without any problems,” explains Kalverkamp. Of course, it will be reforested later, with oak, beech and Douglas fir. The deciduous trees are more resistant and more valuable for the climate. “At almost 70 years of age, I will no longer see them in full size,” says Kalverkamp, ”but the generations to come.”
It was felled at the new moon
In one day, the required spruce trees were felled and some of them were sawn into beams on site. “We worked at Neumond, then the quality of the wood is better,” he explains. For Kalverkamp this is no hocus-pocus, but rather old knowledge about building houses, which has proven itself over centuries and is of course still used on the school farm.
The woods are on a hanger. A few meters further on is the plot of land, which has already been partitioned off with a traffic tape, on which the house is to be built. Some connections are already there. “Now we just wait for the building permit and then we can start immediately.”
Photo gallery
Picture gallery: A house made of wood and clay
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Oak boards dry in bed
The beams that have already been cut should form the substructure. The floor is made of oak planks: “I got the wood cheaply from a forest company.” The boards still have to dry. And what would take a long time in nature is made by the farm’s own wood chip heating system in no time at all.
The school farm has been producing its own heat since 2007. Because wherever there is planing – and that will be a lot in Berghausen – there will be chips.
They are first dried with the exhaust air from the stove and then burned. In the middle of this cozy bed made of drying wood chips, the oak boards await their future as floorboards. Berthold Kalverkamp digs through the lukewarm, fragrant mountain made of wood chips, exposes a few boards and probes them carefully. “They feel good,” he says happily.
The old straw bale house had to give way
Working and building with wood has always been Kalverkamp’s great passion. With a lot of fellow campaigners, he initially implemented his ideas inexperienced and a little too freely. At that time, in their idealism, the nature conservationists hadn’t given any thought to bureaucracy or building permits and were deeply shaken ten years ago when the building regulations office was on the mat. With a joint effort by the city administration and “school farmers”, (building) law and order were gradually created on the farm. Because there was never any doubt about that: the nature and school farm had to be saved.
The old straw bale house was the last “black building” that had to give way. “The straw stored in it was still fresh after many years,” reports Kalverkamp, ”there was nothing musty or damp.” Proof of how good the natural half-timbered construction made of wood and clay is for the indoor climate.
The school farm and nature reserve
A paradise not just for children
- The sponsoring association of the school farmer’s and nature conservation farm (SBNH) has existed since 1991, and the sponsoring association was founded one year later. Together they form the supporting pillars of the courtyard at Zechenstrasse 18.
- The development association supports the school farm ideally and, above all, financially. The latter is made more difficult by the pandemic. Because the court festival and the cultural events, with which most of the money is raised, were canceled.
- The SBNH is also a “green classroom”. School classes garden there and work with the many animals. The Hans Böckler Vocational College in Marl conducts vocational orientation.
More information on www.schulbauernhof.de
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A mix of recycling and upcycling
The straw bale house lives on in the new multifunctional house that will take up the space in the future. All usable building materials are recycled. If not there, the wood is used elsewhere or provides fuel for heating. “Almost nothing goes away with us,” Kalverkamp affirmed proudly. At the end of the demolition, only a tiny part of “useless” material remained: “I paid 35 euros to dispose of it.”
Doors, windows, roof tiles – Kalverkamp also tracks down such things used and cheaply, at best even as gifts. He brought pallets of unfired clay bricks from Vinnum. “The old brick factory has ceased operations, it is being dismantled and rebuilt in China,” he says. He buys the remaining stock at a special price. Next to the gray blocks lie large sacks full of an equally gray, moist mass. “It’s also clay, but from next door,” explains the client and crumbles some of it between his fingers. “Our neighbor has drilled deep into his property, that’s out of the borehole.” Mixed with straw and water, it makes the best material to fill the framework.
Great climate in thick clay walls
But Kalverkamp and his builders also see the new building as a promising project: the roof will be green on the north side and equipped with photovoltaics on the south. The wood chip boiler provides the district heating for the new building. “We also want to collect and recycle the process water.” 45 centimeter thick clay walls made any synthetic thermal insulation superfluous. “They absorb moisture, but also release it again. In summer it is cool, in winter the warmth stays inside. “
But it will take a few more months before that happens. The Recklinghäuser Zeitung will accompany the construction progress and report on it again and again. “And maybe”, hopes Berthold Kalverkamp, ”we will convince others of our sustainable construction.”
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