In nearly all of the major cities across the globe, tall buildings stretch high in the sky. These monumental structures are worn as a badge of honour for that city. Since the late 19th century, these skyscrapers dominated skylines with their concrete faces and steel beams. Looking ahead, this image may warp slightly with the introduction of more environmentally conscious timber skyscrapers.
The introduction of timber into skyscrapers has been ignited by Canadian architect Michael Green and his proposed 35-storey timber skyscraper. The building, which will become the world’s tallest timber-supported tower, will be built in Paris and is known as Baobab after the alien-like trees of Madagascar.
Innovations in ‘mass wood’ and ‘cross laminated timber’ has allowed architects and designers to make more use of the material. These new materials can help create massive timber panels that can comfortably support buildings much taller than traditional timber can. The Baobab will utilise the Cross Laminated Timber to provide the stability and strength required for such a tall building.
The mechanics of the Cross Laminated Timber involved several layers of large timber board being glued together at 90 degree angles, forming thick (up to 40cm) structural sheets. By cutting these thick sheets to size and then shipping them to site, there is little work that needs to be done there. It’s somewhat akin to a jigsaw. This cuts costs, mistakes and time spent when compared to the traditional skyscrapers.
Aside from the logistical benefits of using timber as a major building material in skyscrapers, it is much more environmentally friendly. With the real threat of climate change upon us, the type of building material we use is not usually the main talking point – that tends to be on the energy we use to operate buildings. However, the often overlooked fact is that the carbon footprint of a building is massive before the power goes on. This footprint is massive in skyscrapers, too. It is estimated that around 45 % of the carbon footprint of a building is due to its building materials.
Other factors play a role in the case for timber skyscrapers, such as the ability to protect itself from fire. This rather unusual aspect of a wooden structure involves using an excessive amount of timber as a potentially sacrificial material, should a fire spread. From a fire protection standpoint, mass wood is even safer than steel, and it does not need fire protection like steel does.