Natural building materials & environmental performance

Cross-laminated timber (CLT) and other wood applications with a favourable environmental footprint

The term 'circular building economy' often brings to mind the re-use of building materials in new applications. One well-known example is the use of granulated materials as a basis for raw concrete. Yet the use of wood in the shell construction phase, for example, can also drastically reduce a building's environmental footprint. For example, CLT's potential has been known for quite some time now. Since the environmental performance of a building is gradually becoming a key focus of attention, growable materials and their applications are becoming increasingly important.

The wide range of renewable materials that offer added value in the building industry includes reeds, coconut, hemp and flax, among others. Today, these materials are primarily proving their worth in technical nature-related applications, e.g. for road infrastructure and wildlife crossings, for reinforcing verges, for slopes and embankments, for waterfronts and all kinds of water-robust construction work, and so on. Wood, meanwhile, is becoming increasingly prominently used in building projects, due to its beneficial effect on environmental performance. After all, bearing in mind positive and dynamic European forest management, using wood in constructions achieves a better than carbon-neutral result. Hence the beneficial effect on the environmental footprint throughout a building's entire life cycle.

Consequently, the use of CLT (laminated timber) is becoming increasingly commonplace around the world. Attaching several planks to each other, it is ideal for making solid wooden structures that can replace metal and concrete. In addition to its strength, other benefits include the speed of construction, less noise and less dust pollution, better energy performance and greater aesthetic appeal. However, a preliminary study may be required to achieve optimal acoustic results, too.

In English-speaking countries such as the United Kingdom, the USA, Canada and Australia, CLT has already been used to construct high-rise buildings up to 18 storeys tall. One outstanding example is a building in Vancouver housing 400 Canadian students. But in Flanders too, more particularly in Borgerhout, the construction companies THV D'Hulst Van Rymenant and Thys Bouwprojecten are currently constructing a 2,000 m² office complex designed as a passive building made using bio-ecological materials. Nine beams from Austria, 32 metres long and each weighing 4 tonnes, span the entire building, including its wooden lift shaft.

Mundo-a in Borgerhout, an example of a passive construction built using bio-ecological materials
Mundo-a in Borgerhout, an example of a passive construction built using bio-ecological materials

Over the coming decades, our region will experience a characteristic wave of urban densification projects designed to maintain a sufficient supply of high-quality housing. For example, when adding additional storeys on top of existing buildings, a timber application such as CLT - which is significantly lighter than conventional shell structures - can have added value.