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Sustainable building construction: municipalities go wood

The days when forests died off in Germany are over. In fact, German forests are growing year on year. This is not only excellent news in terms of carbon storage. Using wood also helps us avoid carbon dioxide emissions. More and more cities rely on timber constructions, which have long been used in the high-tech sector. The HolzProKlima competition, coordinated by proHolzBW, has massively promoted sustainable building construction in Baden-Württemberg, highlighting what it can offer in terms of climate protection.

The three-storey senior centre in the town of Frickingen is a barrier-free building and has an energetically optimised building structure. The centre contains 17 apartments and is supplied with locally produced heat. © Gemeinde Frickingen

Basically, using wood in construction is something we have always done and should continue to do in the future. According to proHolzBW, wood is the most natural building material available and every fourth building in Baden-Württemberg is timber-built. There are many reasons for using wood for buildings: as a renewable raw material, wood effortlessly meets all environmental requirements. The various building requirements, from structure to façade, can be met by a broad range of different wood types that provide the right material for every application. The high degree of prefabrication means that timber constructions can be erected more quickly and precisely than concrete or steel constructions, which in turn significantly reduces construction costs. Wood weighs very little and has a high load-bearing capacity, making it suitable for many things: whether it be adding another floor to existing buildings, closing gaps between existing buildings or erecting entire houses. Wood exceeds all regulatory requirements even when it comes to fire protection. In the event of a fire, modern wooden houses burn more slowly and in a more controlled and safer manner than buildings made from other materials.

Glossary

  • Selection in a biological context means the assortment of organisms due to their characteristics. On the one hand, this could be natural selection ("survival of the fittest") like in evolutionary processes. On the other hand, selection by man, e.g. breeding, is called artificial selection. Artificial selection is also used in genetic engineering to identify a genetically modified organism due to its new characteristics (e.g. resistance to antibiotics).

Sustainability is the focus of attention

The town hall in Frickingen with its aesthetic, transparent façade was erected in 2000. The peculiarity of the building is its timber elevator shaft. © Pixelzauber / C. Allweier

If a building is to be sustainable, its lifespan requirements from initial planning, erection, usage and demolition need to be based on ecological and economic factors. From an ecological point of view, the biggest priority needs to be conserving resources, reducing total energy requirements and achieving a lifespan that is as long as possible, including reuse. Once the building is being used, the important factors are insulation, energy sources, water consumption and waste disposal. Last but not least, socio-cultural aspects such as public acceptance and appreciation of a building are also important. Is a building easy to access? Does it have an aesthetically pleasing design? How does it affect people’s quality of life? ProHolz BW GmbH reports on its website that wood makes you feel good, lowers the heart rate and has a positive effect on people’s health. In addition, wood breathes and regulates the indoor climate and humidity.

Timber construction is climate protection in practice

This building yard in Frickingen offers storage space, workshops, offices and social rooms. The whole wooden building takes three people three days to erect as much of it is prefabricated. © Architect Manfred Fetscher, Ilmensee

"Wood meets all environmental requirements and is nice to look at," says Prof. Dr. Werner Sobek, civil engineer, architect and professor at the University of Stuttgart. He sees climate protection as a generational responsibility issue. Above all, the excellent eco-balance is the chief reason for using wood in buildings. "Using timber products protects the climate in two ways: as trees grow, they remove climate-damaging carbon dioxide from the atmosphere that they store until they are burnt. It therefore makes sense to focus on the material use of wood for as long as possible before it is combusted to produce energy. At the same time, timber can be used to replace materials such as steel or concrete that require high energy input to produce,” explains Martin Herzberger from HolzProKlima. "Using one cubic metre of wood instead of other construction materials can save about two tonnes of CO2 emissions.” Wood is also regionally available in sustainably managed, native forests, thus obviating long transport routes that are also a burden on the climate.

Municipalities as role models

The Rupert-Neß high school in the city of Wangen im Allgäu received the 2013 Allgäu Construction Award. © Quirin Leppert

Sustainable building construction increasingly relies on wood. For this reason, the HolzProKlima initiative, a grouping of 14 federal associations and organisations in the forestry and timber industries, aims to inform the public about the ecological and economic benefits of wood and to increase its material use. In 2017, the initiative launched the third edition of a Baden-Württemberg Climate Champion competition that called on all municipalities in Baden-Württemberg to send in project proposals on sustainable timber construction and climate protection. Through this competition, Baden-Württemberg hopes to reinforce its position as the leading region for timber construction. Forty municipalities sent in applications that highlighted where and how they are making increasing use of wood in the construction of buildings. The winners were selected by an official jury. In addition, a special prize was awarded based on 10,000 online reviews. In June 2017, the three best overall concepts were awarded prizes totaling € 20,000. The first prize, worth 10,000 euros, went to the small town of Frickingen on Lake Constance, which has been using its 600-hectare forest for 30 years and, with its conclusive overall concept, has implemented a consistent and responsible timber construction culture that also comes with a local heating supply system. "Whether it be the expansion, renovation or construction of a new town hall, building yard, fire station or senior citizens' centre - Frickingen impressively demonstrates the potential of modern timber constructions in sustainable development and sets a good example," the jury found.

Healthy living with and in wood

The Marienhof building in Leutkirch (Allgäu) was erected on the premises of a former farm and follows the original layout of the farm buildings. © Martin Rudau

For the first time ever, the Baden-Württemberg Minister of Rural Affairs and Consumer Protection, Peter Hauk, awarded two second prizes to the towns of Leutkirch and Wangen im Allgäu in the south of Germany. The residential Marienhof project on the premises of a former farm in Leutkirch had already won awards as a successful joint project that promoted healthy living. Seven individual, timber-built family houses follow the same layout as the original farm buildings. The Rupert-Neß high school three-storey timber construction in Wangen im Allgäu won the German Timber Construction Award in 2013. All visible wooden parts of the school are made of native silver fir, and local wood is used for energy production.

The "Forum Holzbau" passive house in Ostfildern, whose silver fir seminar rooms welcome visitors into a pleasantly fragrant atmosphere, is another example of sustainable building construction in Baden-Württemberg. Equally appealing is the Kleinkindhaus in Heilbronn, a Waldorf facility that accommodates around 30 children under the age of four. The forest pavilion in Schwäbisch Gmünd is a particular gem. It was built for the 2014 Baden-Württemberg Horticultural Show and its outer bionic lining is based on the plates of a sea urchin skeleton. Wood is clearly a raw material of the past, the present and also of the future.

Website address: https://www.biooekonomie-bw.de/en/articles/news/sustainable-building-construction-municipalities-go-wood/