Table of contents:
- THE HOUSE: People love wood because it is ecological and pleasant. Is it also the building material of the future?
- What is the trick in building with wood?
- Can you build high-rise buildings from wood without restrictions? You are currently at eight floors
- So you need a lot of technology in addition to the natural material?
- How does climate change affect timber construction?
- How should the surfaces of wood on the facade be treated in the future?
- Can you renovate wooden facades energetically?
- Can every carpenter do that?
- Is it better elsewhere?
- How can a wooden facade contribute to energy generation?
Video: Living of the future: The building material of the century, wood
DAS HAUS asks one of the leading researchers, Prof. Dr. Stefan Winter: What can wood do? Almost everything - if we develop even better technology and interdisciplinary cooperation.
Prof. Dr. Stefan Winter is full professor for timber construction and construction at the Technical University of Munich. The leading researcher in energy-efficient timber construction initially learned the carpentry profession as a teenager. His grandfather was a forester, his father a sawmill - that is probably why the material fascinated him. "But if someone had said to us in 1978 when I was doing an apprenticeship: 'Please build an eight-story wooden house!' - the master would have shown us a bird."
THE HOUSE: People love wood because it is ecological and pleasant. Is it also the building material of the future?
Prof. Dr. Stefan Winter: With absolute certainty, because it is the only building material available worldwide that really grows sustainably. Wood also stores carbon so that it can reduce CO 2 in the atmosphere to a certain extent. At the end of its life it can even be used energetically. In this respect, wood has many advantages, but also disadvantages. As a natural material, it has natural enemies such as destructive fungi and insects. Prevention through chemical protection has practically disappeared from us. Because wood only has to be used wisely.
What is the trick in building with wood?
It is relatively easy. First, you need to build wood so that it is permanently dry. If the wood moisture always remains well below 20 percent, then wood-destroying fungi are excluded. We have many wooden buildings that are more than 500 years old = " and this dry wood will last another 500 years.
The second trick: prevent insect infestation! In the past, several generations of insects laid their eggs undisturbed in undeveloped roof trusses with a roof covering that was also leaking. The larvae then ate the wood. Today we technically dry the wood so well that the likelihood of infection is significantly reduced. The insects lack the nutrients. We also use a lot of wood in closed wall structures, separated by plasterboard or wood-based panels. Then there is no free approach for the insect.
Can you build high-rise buildings from wood without restrictions? You are currently at eight floors
Yes, forty kilometers southeast of Munich in Bad Aibling. Others are at a hundred meters - for example with the Timber Tower in Hanover, a wind turbine. We are currently planning a ten-story building in Flensburg. We are crossing the skyscraper - for the first time in Germany. There are projects in Vancouver where the architect Michael Green wants to build up to thirty floors. In my view, it is neither a serious static problem, nor is it a serious fire protection problem, nor is it a real insect problem. My biggest concern, if I'm honest, is permanent moisture protection at these heights. You have to get the facade so tight permanently that water doesn't run in anywhere. And you have to think about smart security systems. The Timber Tower is wrapped in a film with a moisture detection system. You can tell immediately when a leak occurs.
So you need a lot of technology in addition to the natural material?
That is only possible with intelligent technology, no question. In a new project with eight floors, the stairwells were even planned in solid wood. Of course with correspondingly non-combustible planking made of two gypsum fibreboards, because of course escape routes must remain fire-free inside. I am sure there will be many developments.
How does climate change affect timber construction?
Over the next twenty to thirty years, the dominance of softwoods will shift drastically towards more hardwood, particularly beech and ash, alder and chestnut. For example, there is now an approval for glulam made of beech. These are the first reactions. The task here is: Hardwoods can not be worked so well with the conventional methods. We will therefore see a change in sawing technology and we are working on the bondability of these woods because they have different ingredients and surface structures, densities and hardness. We know that a whole wave of other woods is approaching us.
How should the surfaces of wood on the facade be treated in the future?
Preferably not at all. Untreated larch grows gray over time. Many people don't like that. That is why, for example, you can anticipate graying with water-based glazes - it becomes more even. Optical accents can be set with water-based paints or mineral paints. This is not necessary to protect the wood.
Can you renovate wooden facades energetically?
This works very well in terms of craftsmanship, for example by screwing wooden frames 16 to 20 centimeters wide onto an existing single-family home, insulating them in between, and installing a panel and a ventilated facade on the outside. We have developed the so-called TES Energy Facade System, which has won many awards in the meantime. Together with our colleagues from the surveying technology, we learned to measure facades very well and fairly cheaply with laser scanning and photogrammetry, then they are digitized in order to obtain the necessary dimensional accuracy. This creates highly individually prefabricated facade elements that are placed in front of existing buildings.
Can every carpenter do that?
Computer-controlled, the woodworking is precise to a tenth of a millimeter - naturally in semi-automated production. Our biggest concern: We have a fairly large demand, but we are currently lacking in sufficient quantities of efficient timber construction companies in Europe that reliably handle large-scale projects. I might have ten or twenty in Germany. But I could use fifty - a real problem.
Is it better elsewhere?
No, rather worse. I was a part-time professor at a university in Finland for four years to advance the multi-storey timber construction … You must not forget that we have developed the building regulations in Europe over the past two decades in many countries from a maximum of two storeys to eight storeys. In the past, this was simply prohibited. Now the construction industry is gradually entering. The big companies say: "Oops, this building material is developing, we want to be part of it."
How can a wooden facade contribute to energy generation?
If we want to build energy-plus houses, we need intelligent facades. That is not possible with the roof as the only crop area. There is a very high innovation potential there, which engineers, architects and technicians can only use together. In addition, there is the urgently needed discourse with psychologists, sociologists and doctors. Building is still archaic.
Photo: Callwey Verlag
Our tip: A more detailed version of this expert interview was published in our book "Building for the Future", which we published on the occasion of the 65th anniversary of the house. In addition to further interviews, you will also find specific planning tips, the latest trends in the construction industry and more.
This article is part of the series: "Living and living in the future". If you are interested, you will find even more exciting topics in the overview.