France: Timber towers are gaining popularity. But why?

12-02-2018

Silva, France’s first attempt at building with wood. Image credit: Art & Build

Timber towers are increasingly taking up headlines, blaring statistics and facts. And in Europe, an entire country has slowly begun turning its back on building materials such as concrete and steel. But though it is late to the game, developers and architects in France are looking more and more to wood as a construction material, driven by increasing worries regarding climate change and the negative effect concrete manufacturing has on the environment.

For most of the 20th century, concrete dominated the architectural industry with its flexibility and relative affordability, leading to a time of bold modernist architecture in France. But today, in a startling reversal, wood is instead praised and sought-after for its smaller environmental footprint and numerous benefits, one of which is the speed in which buildings can be constructed as compared to concrete.

“Wood had largely disappeared and was seen as a quaint material,” partner at architecture firm Art & Build, Steven Ware, said. “But the energy it takes to put a concrete building up, to run it, and then dismantle it when it becomes obsolete was too much. Using mass timber in office buildings seemed like something we had to do.”

There are several contrasts between concrete and wood. For one, cement, one of the ingredients in concrete, is responsible for around five per cent of the carbon emissions found in the world. Trees, on the other hand, capture carbon dioxide that a regular building process produces.

In addition, according to CityLab, there are numerous other advantages construction wise that makes wood more economically attractive than concrete. It is a lighter material, meaning that the building foundations need not be so big or deep, and crane costs are lowered as well, as wood weighs far less than concrete. Moreover, driving a nail into wood takes far less time and energy than for a slab of concrete. And because wood more often than not arrives to the construction site ready to be assembled, entire months can be shaved off construction time, saving not only costs, but energy as well. For example,

The invention of as well as the growing popularity of cross-laminated timber (CLT) also served to catapult wood construction in France. Prefabricated panels consisted of several layers of wood glued together in a perpendicular fashion, they are sturdy enough to hold up large buildings, and are fire-resistant as the outer layers only char slowly, keeping the wood inside protected from burning.

Wooden buildings are popping up all over the world, from London to Canada, and in southwestern France, the city of Bordeaux has promised to build 270,000 square feet of wood spaces annually for the coming 15 years, with the wooden office tower, Silva – of which 80 per cent will be made of locally-sourced CLT – leading the charge.

Moreover, designers and architects alike are beginning to believe that high-rises made of wood are especially suitable for metropolises as they do not bother surrounding areas during construction. As the timber is prefabricated, there is none of the dust and noise usually associated with typical concrete construction sites.

But though wood is quickly gaining traction in France, the nation is still catching up with other countries already further ahead in timber construction. There are still few sites that manufacture slabs of CLT, which are brought in from Austria.

However, one drawback on constructing with wood is its sustainability, as some say that the shift could place even greater demand and stress on existing forests already feeling the strain of deforestation.