Although wood has been used in buildings for centuries, it is the development of solid engineered timber products such as cross-laminated timber that has provided the structural and technical capabilities to create a truly sustainable alternative to traditional building materials such as concrete.
Solid timber products, engineered timber building materials that are manufactured off-site, can provide significant programme and cost savings and bring added environmental benefits such as low energy consumption.
In fact, sustainably sourced timber is the only carbon neutral structural option, with 1m³ of timber storing 0.25t of carbon. It also has a better thermal performance than reinforced concrete, reducing dependence on synthetic carbon-based insulation, and the production process generates zero waste.
From a structural perspective, solid timber can be used for all elements of a building’s superstructure (walls, floor, roof) or within hybrid construction. The cross lamination manufacturing process results in the production of dimensionally stable panels. High in plane stiffness, it provides significant robustness and wall elements that can span as deep beams or cantilevers. The structural capabilities and monolithic spans of solid timber panels are very similar to that of concrete and can be used for similar applications.
Forte Living in Melbourne, the world’s tallest timber apartment, has really demonstrated the potential to push the boundaries of engineered timber use and application. But there have been many other examples over recent years.
Stadthaus, Murray Grove, London, UK
Designed by Waugh Thistleton, Stadthaus previously held the record as the tallest timber residential building in the world. It was the first of this height with not only load-bearing walls and floor slabs but also stair and lift cores entirely made from timber. The entire nine-storey pre-fabricated structure was up and built within nine weeks.
Timber absorbs carbon throughout its natural life and continues to store that carbon when cut. The fabric of the Stadthaus tower stores over 186 tonnes of carbon. Additionally, by not using a reinforced concrete frame, a further 124 tonnes of carbon have been saved from entering the atmosphere. This is equivalent to 21 years of carbon emissions from a building of this size.
Saldome 2, Switzerland
The Swiss Salt Works’ second storage building is the biggest dome made of wood in the world. Opened last year, the roof has a diameter of 120 metres, and the building stands 32 metres high and has an area of 14,500 square metres. This was an exceptional engineering, construction technology and logistical challenge — the entire free-form construction had to be put together by seven engineers, who only had 12 weeks to set it up without any supports.
Saldome 2 consists of arched girders that are held together with steel connections.The average size of the two-sided curved elements is 13 by 2.3 metres, with each weighing around 900 kilograms.
The Hive, Worcester, UK
On a riverside site in Worcester city centre, this highly sustainable building, the first joint-use library in the UK, serves both the University of Worcester and the general public.
The project team developed an innovative way of using parametric modelling to explore design ideas, enabling the manipulation of form within the boundaries of the structural and environmental constraints, and resulting in a design which replaces 250 tonnes of steel in the roof with laminated timber, saving an estimated two months of design work and more than 2,000 tonnes of CO2. This research won first prize at the International Bentley Awards in the Innovation in Generative Design category.