Making buildings more sustainable with timber

27.08.2020 / Kasper Kristensen, COWI and Daniela Grotenfelt, Arkitema Architects

As cities grow, so does the demand for new buildings. This has a significant, negative impact on the climate if we do not shift to more sustainable construction methods and materials. Timber lets us reduce the environmental footprint of construction and create safe, healthy and beautiful buildings for the future.

Buildings and construction account for 39 per cent of the world’s CO₂ emissions. Traditionally, with the largest part of the energy consumption being used for the operation of buildings. But as national authorities have imposed higher and stricter requirements for how to heat and insulate our buildings, the scenario has changed.

As the world’s building stock is set to double by 2060, we need to reduce the climate footprint of construction and materials. 

Today, many buildings use more energy during the first year of their lifetime than the following 80 years, meaning that more than half of a building’s energy consumption is used for construction. To fight climate change and create more liveable cities, we must continue to optimise energy usage of existing buildings. However, as the world’s building stock is set to double by 2060, we also need to reduce the climate footprint of construction and materials.

With timber, we can come a long way. A material that we have built with for thousands of years. And now the industry is ready to take the next jump thanks to technological developments and a growing demand for sustainable buildings. 

A RENEWABLE RESOURCE GROWING ON SOLAR ENERGY

Studies show we can reduce CO₂ emissions from the construction of buildings by 30 to 70 per cent by using timber instead of conventional building materials. And every time 1 m³ of timber is used instead of 1 m³ of concrete, we save one tonne of CO₂, which is equivalent to 400 litres of petrol or diesel not being burned.

Timber is a renewable resource that grows on solar energy while capturing CO₂ from the atmosphere. All things being equal, timber production and manufacturing have a low energy consumption. And when sourced from certified, sustainable forestry, timber production protects biodiversity and forest growth.

The largest part of building materials is used for load-bearing structures. Therefore, replacing conventional building materials with timber for this purpose results in the biggest environmental benefits and CO₂ reductions. And this is possible since timber is both a durable and long-lasting material.

That way, timber is one of the keys to making construction greener. However, to fully realise its potential, it is necessary to always evaluate the climate footprint of buildings through life cycle assessments (LCA). And to enhance the reuse of timber materials by focusing on flexible and design-for-disassembly solutions. 

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  • COFFEE FACTORY, VESTBY, NORWAY: The new coffee factory is the first factory in Norway built in solid timber. It is built in cross-laminated-timber (CLT) and glulam frame structures and includes a production building, warehouse, and packaging and delivery facilities. 1.280 solar panels are located on three sides of the factory building as part of the facade elements. A factory building with ceiling heights of up to 35 meters and a total area of 11.500 m² made of solid timber is challenging and a lot of time was spent on ensuring safe and risk-free installation during construction. Architect: Astrup & Hellern

    © Straye Gruppen

  • UNIVERSEUM SCIENCE CENTER, GÖTEBORG, SWEDEN: The Universeum’s mission is to stimulate young people’s thirst for knowledge and encourage them to get actively involved in science and technology. The main materials are wood, glass and concrete; all chosen with future recycling in mind. The building is to act as a model of good environmental practice in every possible way; its energy consumption is low and the energy used in its day-to-day running is, as far as possible, to be harnessed in the building itself. The vertical joints of the opaque glass screen are covered with wooden frames making the building appear all wood from the main approach. Architect: Wingårdhs

    © Åke Lindman

  • BJØLSTAD STUDENT HOUSING, NORWAY: The new student accommodation is constructed in solid timber in extension of the existing student housing. The u-shaped building contains single rooms as well as shared accommodation for eight people, organised around a common hallway. There are several common features such as a study and a common room, as well as outdoor sheds and bicycle parking. The project is a 5-storey CLT structure presenting exposed wood on the inside and on the facade. Architect: BAS Arkitekter

    © Erik Burås

  • ÅSVEIEN SCHOOL, TRONDHEIM, NORWAY: The school is a new primary school for the youngest pupils up to 7th grade. In addition to regular classrooms, the new school houses a sports hall, canteen and auditorium. The school is 11.000 m² with space for 630 children. Åsveien School is a FutureBuilt project aiming for a 50% reduction in CO₂ emissions. The project demonstrates an extensive use of timber and re-used materials. The school is a passive house and one of Norway’s most climate-neutral schools. Architect: Eggen Arkitekter

    © Eggen Arkitekter

  • KRINGSJÅ STUDENT HOUSING, OSLO, NORWAY: Kringsjå consists of two blocks of 9 to 11 floors with 349 student homes. The buildings are constructed as solid timber passive houses, which makes them almost energy-neutral and self-sufficient regarding heating and hot water. Kringsjå is a FutureBuilt project that has obtained an outstanding reduction in CO₂ emissions. The project includes climate measures such as solid timber CLT panels for the load-bearing structure, use of renewable energy (solar cells and geothermal heat), focus on local rainwater management, focus on choice of materials in relation to greenhouse gases and indoor climate, new pedestrian and bicycle paths and bicycle repair workshops. Architect: AT Plan & arkitektur

    © Tove Lauluten

  • ROMSDAL HIGH SCHOOL, MOLDE, NORWAY: The new Romsdahl High School is the largest school in Scandinavia built in solid timber. It has floorage of 12.000 m² and room for 950 pupils. The school is a business school and contains traditional class rooms in connection to special subject rooms as well as a new canteen. It is a passive house with an exposed timber structure on the inside and a wooden facade. The main purpose of the use of timber was to reduce the CO₂ emissions and to encourage the use of sustainable forestry in the construction industry. 11.000 trees, half a cubic metre each, for this construction project. The trees were used entirely – nothing was wasted. Architect: HUS arkitekter

    © Kjell Herskedal

  • FINANCIAL PARK, STAVANGER, NORWAY: The new SR-Bank head office is a new landmark in Stavanger totalling 22.500 m². With seven floors above ground and three floors below, it is one of Europe’s largest commercial buildings built in timber. The main structure of the 13.500 m² over ground is made of timber. Concrete was used for the stabilizing staircases and the 9.000 m² underground structure. Facades are primarily glass structures and the roof is a green roof. The project is BREEAM Excellent certified. Architect: SAAHA + Helen & Hard

    © Sindre Ellingsen

  • OFFICE HEADQUARTER, DENMARK: The new office building will be one of the largest office buildings in Denmark built in timber. The building is constructed with a four-storey atrium supporting the unity and flexibility of the building. Timber beams and columns are chosen for the load-bearing structure including CLT panels at floor levels, which allows for a light-weight structure and a low carbon footprint from the building. All consultancy services including leading experts within timber construction are provided by COWI and Arkitema.

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Cost-efficient and fast to assemble

Being a light-weight material, fast and easy to assemble, timber can also make construction processes more efficient. Timber:

  • requires less resources when transported and assembled compared to conventional materials.
  • allows for the use of larger elements, fewer crane lifts and lighter foundations.
  • reduces the extent of transport needed to and from buildings sites.
  • shortens construction time with the potential of putting buildings into operation faster.

To achieve the economic benefits and make high-quality timber buildings, contractors must know how to design, handle and build timber structures efficiently. To that end, sharing best practices from countries with a long tradition of and great expertise in timber structures, like Norway and Sweden, can help the industry move forward.

Safe, healthy and beautiful to live in

Besides their green and economic benefits, maybe most importantly, timber buildings are also good for people to live in.

Given that we spend up to 90 per cent of our day inside, creating a healthy and appealing indoor environment is crucial to human well-being. In addition to its versatile and aesthetic values, studies show that timber also has positive effects on our health and productivity. People relax when surrounded by natural elements, which explains why timber can help reduce stress levels. Moreover, studies show that timber can even improve the healing of patients and support constructive learning environments.

In addition to its versatile and aesthetic values, studies show that timber also has positive effects on our health and productivity.
Finally, despite being a combustible material, it is just as safe to live in timber buildings as in any other building since all buildings must comply with the same criteria for fire safety. And, in the unfortunate event of a fire, modern technology allows for better fire control, making load-bearing structures with solid timber walls and beams a viable and safe solution. 

Multi-storey timber buildings are the future

The past 20-30 years we have seen a greater demand for multi-storey timber buildings. With the development of solid wall and floor panels, e.g. made of cross-laminated timber (CLT), we can build higher and safer using timber. Now, buildings with load-bearing timber structures can be built in 8+ storeys. 

The combination of modern timber technology and increased attention on environmentally friendly building materials have made timber structures more popular. A trend we expect to continue as national authorities are starting to set stricter requirements for the energy consumption in the construction phase, and as more developers and clients are asking for more sustainable alternatives.

All in all, thanks to its architectural, technical and environmental qualities, timber has the potential to become the preferred building material of this century.

 

COWI and Arkitema Architects are among Scandinavia’s leading architecture and engineering companies. We work strategically with sustainability and we have formed an advisory team of specialists within timber construction. Learn more about how we work with timber – download brochure.

Get in contact

Kasper Kristensen
Senior Specialist
Buildings, Denmark

Tel: +45 56401072

Get in contact

Daniela Grotenfelt
Head of Sustainability
Arkitema Architects, Sweden

Tel: +46 708 348 453

MEET THE EXPERT

As a structural engineer, I am driven by a sustainable ambition for future buildings. I believe that we, as designers, have an opportunity to choose building materials that are highly durable, easy to assemble and reuse, and even manufactured using green energy. Through my professional career, I have focused my expertise in the field of load-bearing structures, advanced timber and architectural structures. During my research at DTU, I did my specialisation in wood technology and timber engineering, and I am confident with the nature of wood as building material. As key specialist, I am part of the timber network in COWI and Arkitema Architects; a Scandinavian advisory team of leading specialists within timber structures. We provide locally based consulting services within architecture and multi-storey timber structures throughout Scandinavia.

MEET THE EXPERT

As Head of Sustainability at Arkitema Architects, I work across Scandinavia to lead our organisation towards a sustainable future. The construction industry is responsible for a large part of the GHG emissions and by using timber on projects, we can decrease the carbon footprint of our industry appreciably. During my career as a sustainability specialist in the Nordic countries and Russia, I have led projects through all development phases from design to maintenance, renovation and disassembly. Timber has been present from the start and I am happy to be leading the timber experts in COWI and Arkitema Architects, who seek to change the market through close knowledge sharing and collaboration between leading experts.

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