by Bhavi Mandalia
“It depends on what you make of it,” was the name of an advertising slogan for concrete, which should probably mean that the material is not only versatile, but also that its qualities depend more on the type of design than on the building material. The new material of the hour is called wood.
It is durable, stable and inexpensive and you can use it to produce anything between a villa and a high-rise, between a commercial hall and carpentry interiors. Wood always has the CO2 balance on its side – at least when it is processed in the region in which it grew.
This trend is pressing concrete as the most important building material. At a time when potential environmental pollution is becoming more and more relevant, this fact is noticeable negatively: The concrete industry accounts for around eight percent of the global Carbon dioxide emissions.
But this aspect is suppressed in many energy balances because the so-called gray energy is hidden. This is all the energy that a building consumes during construction, use and demolition.
This is different with wood, because it binds carbon dioxide, around one tonne per cubic meter, over decades and centuries.
Threat to brick and concrete
No wonder that the demand for wooden structures is increasing. The construction industry is experiencing headwinds from the wood industry and has recently sounded the alarm: “Solid buildings can best compete with wood structures in harmony with sustainability, i.e. the sum of all ecological, economic and sociocultural properties”, according to a statement from 33 organizations and Associations of the German construction industry.
The appeal was addressed to the building ministers’ conference in Weimar on September 24th. In it, the building ministers of the federal and state governments were asked not to allow any quota regulations for individual building materials or construction methods.
Wood is the greatest threat to brick and concrete. The fact that it has developed into a veritable alternative is due to technical innovations that have now become widely accepted.
The industry has been working with cross-laminated timber or cross-laminated timber for around 20 years. The layers that are glued crosswise to each other prevent the wood from “working”.
Cross laminated timber can be used for the construction of external and internal walls as well as ceilings and roofs. Additional insulation and facade elements can be attached to it.
Or you build in such a way that additional elements are unnecessary. The company Thoma from Austria has developed solid wood houses that do not even require gluing: the panels made of untreated wood are held together by wooden dowels.
Wood as a building material is also experiencing a revival in Germany
Houses made of wood instead of concrete and steel. In recent years, more and more houses in Germany have been built with this renewable raw material.
Source: WELT / Angela Knäble
Fine wooden ducts are milled between the panels for thermal insulation, further insulation is not required. The house is made entirely of wood, except for the building services.
The glue, from which some fear chemical vapors, does not pose any health risks. The volatile organic compounds from wood and wood-based materials have now been examined many times and found to be harmless.
Long gone are the days of formaldehyde, which once stood for dangerous vapors from chipboard. In 2016, scientists from TU Wien showed in two 30-square-meter model rooms made of cross-laminated timber and OSB panels that the natural vapors from the wood and the adhesives used decreased significantly within six months.
Houses made of wood are supposed to conquer the cities
Not brick on brick, but beam by beam is the motto on some construction sites in Germany. Even skyscrapers are now being built with wood, a trend that is slowly growing and that the federal government supports.
Source: WELT / Matthias Heinrich
And that people also influence the indoor air with their activities. Peeling an orange released more emissions in the rooms than the wood used. Another study shows that the natural vapors are not only harmless: the heartwood of pine also has an antibacterial effect.
Typical hospital germs die faster on it than on plastic surfaces made of polyethylene and melamine and it is just as hygienic as plastic, glass or lacquered beech. Wood could therefore be the ideal building material for living, working and healthy.
The construction industry does not want to leave this in its appeal. The properties of solid buildings are, among other things, equivalent to or better than other construction methods in terms of summer heat protection, noise and fire protection, for climate-adapted building and in terms of minimal transport routes. And, according to the 33 associations, you can get away with bricks and concrete cheaper than wood.
“Out of Woods”: 31 wooden houses from all corners of the world
But of course you can also build beautifully with wood. This is shown by a collection of objects that Gestalten Verlag has compiled. Under the title “Out of Woods” 31 houses from all corners of the world will be presented.
Above all, they make one thing clear: there are few limits to the creative and constructive imagination with wood. There are modern buildings with a lot of glass, with others the wooden facade is clad with steel, others create modern architecture with old, reused beams.
Outstanding in the sense of the word are high-rise buildings and large apartment blocks. They show that timber construction can also offer solutions for the tasks of mass housing construction and urbanization.
The BIG office in Stockholm built 169 apartments that were assembled from prefabricated wooden modules measuring 3.6 x 3.6 meters – but not simply stacked on top of each other, but arranged as a rising and ring-shaped complex. In addition, the modules are offset from one another so that protrusions and recesses arise.
The tallest wooden skyscraper to date has also been built in Scandinavia. The tower, which recently stood on the shores of Lake Mjøsa in Norway, measures a total of 85.4 meters. The mixed-use tower was opened after less than two years of construction and was designed by the Norwegian firm Voll Arkitekter from Trondheim.
The 18-storey high-rise towers over the houses of the 10,000-head community of Brumunddal. In addition to 72 hotel rooms from the 8th to the 11th floor, floors for offices, a restaurant, an event hall on the 17th floor, 33 apartments and a publicly accessible roof terrace were integrated into the timber construction.
Architect of the Exile Museum
Architects and engineers have found time and again that the supposed fire hazard is an issue above all for builders. According to statistics from insurance companies and fire departments, this concern is unfounded, because they regularly show that wooden houses burn just as often or just as seldom as those made of stone.
The prejudice that fires are more dangerous in wooden houses is also not true. When it is very hot, the first thing that forms on wooden beams and columns is a carbon crust that protects the load-bearing core. This layer can even be created artificially by flaming the wood in a controlled manner; it is one of the oldest fire protection methods in the world.
It works completely without chemicals and also protects the wood from the weather and insect damage. So it is no coincidence that the world’s oldest surviving wooden structure, the Horyu-ji Temple in the Japanese province of Ikaruga, was treated this way – it was built in AD 607.