Cambridge group says sustainable building material could grow on trees

The construction industry is not known for sustainability.

Concrete is humanity’s most consumed material after water, and its production contributes massive amounts of carbon dioxide to the atmosphere. And the production of every tonne of steel releases 1.83 tonnes of CO2. 

The Centre for Natural Material Innovation (CNMI) at the University of Cambridge thinks the answer could grow on trees. Timber from managed forests sequesters huge amounts of CO2, and the CNMI believes it holds promise for building massive skyscrapers to tackle the global housing shortage while fighting climate change. The centre gave the public a glimpse of the future at the Royal Society in the summer by exhibiting a mock-up ‘timber tower’ apartment from the proposed Oakwood building in the Barbican, London. 

LVL up

Timber is naturally anisotropic, meaning it does not have the same properties in every direction. It can be made into more regular materials, however, such as laminated veneer lumber (LVL) or cross-laminated timber. LVL is more homogeneous and stronger than timber, and cross-lamination protects against fire risk – especially relevant for 300m towers. They are lighter and more flexible than concrete or steel, and the CNMI believes they could be a perfect alternative for skyscrapers. 

Challenges remain, however. “There’s no design confidence in the UK, mostly because timber hasn’t been a primary source of structure material so far,” said the CNMI’s Eleni Toumpanaki. “Engineers are not confident to design with timber because they don’t know the typical connection details, for example, or construction forms of timber. But this is something we can address in the future.