Wooden buildings are currently making a comeback in southern Germany. The construction sector is buzzing with new ideas for creative new constructions. Architects and homebuyers are getting excited about building in wood, and the possibilities seem limitless. In the German federal state of Baden-Württemberg alone, wood construction has surpassed 30% in recent years. And this trend is going up.
ProHolzBW GmbH is a hub for forestry and woodworking organizations that promotes the use of wood in Baden-Württemberg. Their job is to support organizations along the value chain, from the forest enterprise all the way to the end consumer. Simply put, they put forestry and the wood industry on the map. Its manager, Jan Bulmer, is in many ways the right man for the job. After learning carpentry, he studied forestry at the University of Applied Forest Sciences in Rottenburg, as well as timber products and management at the University of Applied Forest Sciences in Salzburg. His organizations credo- “to inspire for wood” (in German: “Wir wollen für Holz begeistern”). Our originally planned 30 minutes interview turned into an intense and exciting, almost two hours lasting conversation about wood construction, its potentials and challenges for Germany and Baden-Württemberg. Here’s a condensed version of our inspiring discussion.
This comeback is not random
The comeback of wood construction did not just happen overnight. It is the result of decades of incremental research and development. Building materials and construction techniques improved considerably. Jan remembers his carpentry apprenticeship 20 years ago. Since then a lot changed in materials and construction. Aside from high standard sawn timber, wood is processed into structurally optimized building products known as “engineered timber”. Products like cross-laminated timber and pre-fabricated elements are much better these days.The development goes on. Jan believes “we have to think in hybrid solutions. We have to think in concrete and wood combined. Concrete, steel, all have certain properties, which wood can complement”. He adds that the amount of wood in such hybrid construction has increased, and will continue to do so.
Construction techniques also changed and became more efficient. Nowadays, pre-fabricated modules are brought to construction sites and assembled on the spot. This makes wooden construction fast, and ensures high quality standards. With such advantages, wooden buildings became a serious contester to traditional constructions. Jan recalls one particular moment when this became obvious: “We showed what wood is capable of by constructing high quality buildings, in a short amount of time, during the refugee crisis. This impressed the decision makers, proving that it is possible to come up with fast, sustainable solutions to the growing housing crisis.”
Wooden buildings are capable of delivering high quality solutions in urban areas. Many cities struggle to provide available and affordable housing for a growing population. Providing affordable spaces in building-site planning for new housing projects is usually the biggest challenge cities face. Jan points out that wood can play an important role in urban densification, by helping increase the number of residences through stocking up existing buildings. Thus, it is possible to provide new spaces in urbanized areas without wasting open spaces in city centers. This is a great opportunity to help cities save space while still providing residential property.
The city of Freiburg in the southern Black Forest is a good example where such modular wood constructions arose during recent years. The first picture below shows a refugee center made of prefabricated cross-laminated timber modules. Four of them where built in less than six months, providing spaces for more than 1000 people. The modules where designed to provide high quality living to ensure that a post-refugee usage is possible (for example student housing). The second picture shows one of the city’s historic buildings with an additional story offering 400 square meters of extra space. Jan points to the minimal impact that this construction had on traffic and pedestrian movement during the construction period. Because of the pre-fabricated timber structures, adding the extra story only took three months resulting in a minimal impact on the city’s daily life. This is a good example of how future construction sites could look like.
An important part of the bioeconomy
Wood is an important resource for bioeconomy, not only for the construction sector, but also for other applications and products. Jan gives the example of wood-based carbon fiber, which could be valuable for the automobile industry in Baden-Württemberg. “Compared to other materials, wood harvesting needs little energy, it is not degraded or mined but managed sustainably”, he points out.
One of the main objectives of the German and European bioeconomy strategy is to reduce carbon emissions and mitigate climate change. Wooden constructions are part of the solution, as timber products store approximately one ton of CO2 per one cubic meter of wood. Carbon is stored through the building’s entire life span. At the end of its life cycle, materials can be recycled or used for bioenergy. The big advantage of wooden buildings is that “you can build, rebuild and recycle” without harming the environment.
Jan believes that wood has the potential to create jobs for the bioeconomy. He considers wood as the perfect example of a regional, natural, renewable product. Working with this material, as people have done for centuries, helps keeping rural areas alive, and most importantly pass local knowledge to the next generation. When bioeconomy strategies talk about job creation, they usually refer to high-tech jobs. However, traditional knowledge and skills combined with modern materials and tools provide the perfect opportunity for integrating local knowhow with the bioeconomy movement. Additionally, “wood can be a testimonial, to rise the sensibility for urban people to think of local areas”.
Many advantages over conventional building materials
So what are the arguments for choosing a wooden building over a conventional, concrete building? Jan thinks it’s the combination of speed and quality that wins the race. Building in wood is very fast as our examples show and they are cost effective. Additionally, the building process offers a lot of flexibility to the customer. Individual solutions can be implemented easily, for example structural adjustments for intelligent housing. Another advantage is that homeowners can move into their new house immediately, without having to wait for it to dry (as it is the case with concrete structures).
Wooden buildings can also offer a bigger living space. The wall diameters are slimmer, compared to thick concrete walls and provide good insulation. Wooden houses always maintain a constant, pleasant room climate. Wood is hygroscopic, meaning it is capable to store and release water. If the room is too humid, it absorbs water from the air; if the room is too dry, it releases moisture. Massive wood constructions also bring surprising health benefits. A recent Austrian study at a primary school shows the health-promoting and stress lowering effect of wooden structures on children enhancing their wellbeing. Especially the smell of pinewood has the effect of lowering the heart beta rate while sleeping.
But what about the price? Many people in Germany think that wooden buildings are around 10% more expensive than concrete buildings. Jan points out that that is not entirely correct. The 10% price difference generally occurs when builders try to adapt a planned concrete building into a wooden one. This usually happens when houses are first planned in concrete, and then complemented with wooden parts during the construction process. “If you plan in wood from the beginning, wooden houses are in the same price class” . Additionally, wooden buildings are cheaper to maintain. In contrast to conventional buildings, a wooden building also pays off at the end of its life cycle. With the right construction concept, wood is easy to recycle.
There are still many challenges to face, such as time-intensive regulations, forest management challenges, and also negative public perceptions . According to Jan, there is a general lack of knowledge about wood constructions from a series of stakeholders, including architects, engineers and investors. In addition, the forest products sector has a lack of skilled workers. The number of apprentices and young skilled workers would need to increase if more wooden buildings are to be built in Germany. Jan’s organization makes efforts to attract and engage young students who want to learn this trade.
Additionally, regulations need to be adapted if wood constructions are to become more mainstream. At the time, local planning and building laws often limit the height of multi-story wooden constructions. Germany has no countrywide building law, some federal states allow multi story buildings, others don´t. Therefore, building in wood often requires individual permits, which are often time-intensive and costly. But this is about to change soon, according to Jan.
Forest management plays an important role in ensuring that the needed timber quantities, and adequate dimensions, come from sustainably managed forests. Particularly softwoods (spruce, Douglas fir or pine) are cheap, plentiful, available in useful dimensions, and can be easily manipulated into engineered timber products. This makes softwood an attractive choice for efficient and sustainable construction. According to proHolzBW, the forest in Baden-Württemberg grows by around 3.8 m3 per second, about one house every three minutes. Jan emphasizes that “spruce is the backbone of our forest industry” and points that the Black Forest has the potential to provide the needed amounts of timber. However, he also acknowledges that spruce monocultures are bone of contention between the forest industry and environmentalists. Without locally sourced softwood however, the construction sector will likely turn to timber imports from abroad to meet its demands.
Lastly, Jan considers that more work needs be done for improving the image of wooden buildings. Many misconceptions are still remnant from times of war in Germany. One of the most common misconceptions is that wooden buildings burn fast, although meanwhile timber frame buildings meet the functional safety requirements for non-combustible steel or concrete buildings. Jan is confident that such perceptions are changing as well, as more wooden buildings will appear, customer perceptions will change.
The way forward
Wood constructions are far from mainstream but have great potential. Jan dares to dream big, and hopes that within the next decade, half of the buildings in Baden- Württemberg will be made entirely out of wood or retrofitted with wood-based materials. In order to reach this goal, he emphasizes that more acceptance of wood is needed. The wood supply chain is an important part of the bioeconomy. Around 200.000 workers are employed by the wood industry in Baden- Württemberg. Wood has the potential to continue providing jobs for skilled workers while at the same time offer more sustainable living solutions for cities.