Legislation coming into force this year indicates the direction of travel for many European countries, with the European Commission introducing the requirement for embodied carbon calculations in its regulations for buildings. These requirements turn the spotlight on timber, due to its lower embodied carbon and its ability to act as a carbon sink.
From January this year, Sweden requires developers to submit embodied carbon calculations for the whole lifecycle of a new building in order to receive planning permission. The next step will be to set limits for embodied carbon, which could come in 2027.
France also brought in new regulations at the beginning of 2022: its RE2020 regulations require embodied carbon analysis over the lifecycle of residential buildings, a requirement that will extend to other building types from 2023. RE2020 also introduces embodied carbon limit values which will tighten in stages over the years.
France also has goals for using bio-sourced materials, such as timber, in its public buildings. Currently its legislation calls for bio-sourced materials to be used in at least 25% of major refurbishment or new build public projects from 2030. Bill number 5166, which came before the Assemblée Nationale in March 2022 calls for those goals to be toughened up to 25% by 2025 and 50% by 2030.
More nations will follow suit. For instance, Denmark’s National Strategy for Sustainable Construction, published in April 2021, says that it will start phasing in the requirement for life-cycle assessments for new buildings, starting with those over 1,000 m2 in 2023. Other buildings will be gradually phased in, as will limits for carbon emissions from construction.
Scandinavian countries have traditionally taken the lead on timber construction, benefitting from both plentiful supplies of wood locally and progressive attitudes towards protecting the environment.
Sweden has run a raft of programmes to encourage the use of wood in construction over the past two decades. Currently, itsBioInnovation Programme aims to change the Swedish economy to a bio-based one by 2050, with the Swedish timber industry at the heart of that ambition.
One Swedish lead worth following is the city of Växjö, which set itself the targets of making 25% of new buildings timber-based by 2015, and 50% by 2020. Back in 1994, after Sweden’s building codes changed to allow timber to be used in multi-storey buildings, Växjö led the way with a five-storey timber building. Since then, there have been many more timber buildings including the nine-storey Vallen apartment building, constructed in 2015.
Norway has been on a similar timber trajectory with multiple programmes to encourage innovation in wood-based products and a move to a bioeconomy. Its 2015 National Strategy for the Forest and Wood Industry, SKOG 22, aims to quadruple the value it creates from its forests and woods by 2045.
Norway is home to Mjøstårnet, officially the world’s tallest timber building at 18 storeys and 85.4m and located on the on the shore of lake Mjøsa. Designed by VollArkitekter and completed in 2019, the mixed-use building was constructed from glulam columns, beams and diagonals, with cross-laminated timber lift shafts and balconies.
Norwegian producer Tewo, which makes prefabricated, insulated wall elements, is on the Puro.earth marketplace, demonstrating the wider commercial possibilities for carbon sequestering products and technologies. Finland-based Puro.earthis a market place where technologies that remove carbon at an industrial scale and store it are turned into digital tradeable assets.
Finland’s National Wood Construction Programme, ran between 2011 and 2015, over which timeframe timber’s market share of multi-storey buildings rose from 4% to 10%. In 2020, the Finnish Government announced new national targets for the use of wood in public construction: 31% market share for wood by 2022 and 45% by 2025.
In Espoo, Finland, there are plans to build the country’s tallest timber building, KeilaniemenPortti, for pension fund Varma Mutual. The 60m-tall building, designed by architect Soini & Horto, will be home to offices, a conference centre, restaurant, sauna and rooftop terrace. Varma wanted the building’s embodied carbon to be as low as possible; in response engineer Ramboll designed a hybrid structure which has concrete stairwells and lift shafts and a timber shell.
Finland’s Helsinki is also home to Wood City. Taking up an entire block of the city, the development uses only wood above foundation level and comprises an office block, two residential buildings, a hotel and a car park. The office building, which is home to mobile game developer Supercell, is the tallest timber building in Helsinki, designed just after the Government changed regulations to allow timber buildings to be up to eight storeys high, rather than four.
In the Netherlands, the city of Amsterdam is setting the pace, mandating that its 32 municipalities will construct 20% of their new housing from wood or other biobased materials, such as hemp or cork. The agreement, which was signed in October 2021, says that for single homes at least 80% of its construction must be timber or biobased; for buildings up to 10 storeys it must be 65%; and for buildings above 10 storeys at least 50%.
In February this year, Amsterdam announced its plans to build a new neighbourhood in the south of the city, the Mandela Buurt, entirely from wood. This year also saw the completion of HAUT in Amsterdam, a 73m-tall residential building designed by Team V Architectuur and engineered by Arup as an innovative hybrid timber-concrete structure, reducing carbon emissions by 50% compared to traditional construction.
Closer to home, Scotland already builds around 85% of its new homes using timber. However, the Transforming Timber initiative, led by BE-ST, formerly the Construction Scotland Innovation Centre, aims to increase the use of sustainable, home-grown timber in the whole of the UK. In Wales, Home-Grown Homes, led by Powys County Council and funded by the Welsh Government and EU Rural Development Programme aimed to do the same thing for Welsh timber. The programme ran from 2018 to 2021, with a further phase currently under consideration.
Meanwhile, the UK government is currently working on a policy roadmap to increase the use of homegrown wood in construction, as part of its England Trees Action Plan. A key element of this policy is to increase tree planting rates across the UK to 30,000 hectares per year by the end of this Parliament. However, with just 14,000 hectares planted in the year to 31st March 2022, the government is far from meeting its targets. Currently just 22% of English new-build homes aretimber-framed, which outlines the opportunity for significantly increasing the use of timber in housebuilding.
Another UK initiative led by the Department of Education is the GenZero project which aimed to develop and test ideas for the next generation of sustainable school buildings.
Two school prototypes were developed and an innovative ‘kit of parts’ was developed to enable maximum standardisation and to minimise the use of carbon. Timber was the only option to meet the low carbon targets and approximately 85% of the final prototypes were designed with panellised cross-laminated timber (CLT), together with glulam and volumetric steel frame modules. You can read about theGenZero prototype classroom that was showcased at COP26here.
As well as demonstrating what is technically possible with timber construction, the wide variety of projects around Europe demonstrates that some of the other constraints to building with wood can also be overcome. These include the inter-related factors of out-datedbuilding regulations, concerns over fire, insurance and funding.
Some pan-European programmes are seeking to aid in the sharing of information and practice between countries to overcome such constraints. Build-in-Wood has signed up seven European cities to act as demonstrators and provide case studies and knowledge. Built by Nature has established an Accelerator Fund which is financing diverse projects aimed to break down barriers to timber construction, in countries including the Netherlands, Spain and the UK.
In addition to these initiatives, and regulation-driven changes due to Governmental carbon targets, there is the influence of the private sector. The companies that have backed these timber projects, and the organisations that choose to invest in or rent the spaces created see a greater value in timber buildings for their shareholders. This is a force that is increasing fast and will continue to do so.