Rising high with wooden skyscrapers

The idea of wooden skyscrapers, or as they are more commonly known in the industry, “woodscrapers”, may sound to many like an odd mixture of medieval construction techniques and futuristic architecture, but it is no longer fantasy. Architects and planners worldwide are coming up with innovative designs and concepts for these buildings, striving to be the one to construct the tallest wooden skyscraper – and in so doing are pushing the limits of building with wood.

At 84 metres, the 24-floor wooden skyscraper HoHo in Vienna held the world record upon its completion in 2018. But plans are already afoot in Japan for a woodscraper that will eclipse the Viennese HoHo four times over. At 350 metres, this Tokyo skyscraper is raising the standards of wooden constructions.

The static ability of wood is immense

If it is used intelligently, wood can withstand similar stresses to steel or reinforced concrete. The technical-mechanical qualities of the strength and load capacity of wood are comparable to these materials. And the relatively low weight of wood alone is also to its advantage: building the foundations for wooden constructions requires little effort. And while wood may well be a flammable material, the combustion rate is meticulously calculated during construction to ensure a high degree of fire resistance. Carbonised wooden beams still hold true long after conventional steel supports would have given way in high-temperature fires. With well-planned fire prevention, there is no reason why wooden buildings can’t rise to meet the heights of others.

Almost all wood

Until now, wooden skyscrapers have always been a hybrid construction. Using wood alongside other materials, such as concrete, has meant that greater heights can be achieved. However, the wooden component of hybrid constructions is becoming greater: in the HoHo in Vienna, it is 75% and the Japanese construction is aiming for up to 90% wood.

Also in terms of the environmental impact, this naturally sustainable and climate-neutral material has a further advantage: compared to concrete, wood retains more greenhouse gases than it emits during its production, processing and transportation – and so becomes a kind of CO2 store. In a manner of speaking, villages and towns made up of wooden buildings would act as a kind of alternative forest because the carbon would remain contained within the wood. For example, during the building of the HoHo in Vienna and compared to conventional construction methods using steel and concrete, around 2,800 tonnes of CO2 were saved – which is equivalent to driving your car 40 km a day for 1,300 years.

At EGGER we have taken our first step in the creation of a multi-storey wooden building with architect Bruno Moser and the construction company Saurer which specialises in building in wood. At our main site at St. Johann in Tirol we have created our "EGGER Stammhaus". This four-storey office building is comprised primarily of the wooden composite OSB 4 TOP – and is a clear demonstration of how successful wood can be in large, multi-storey design.

Step by step, floor by floor

The advance of wooden skyscrapers and the first actual buildings demonstrate that the future is wood, reaching high to touch the sky – an attractive yet modern way in which to combine nature with city life.