Unlocking Timber's Carbon Credentials

Questions surrounding the levels of embodied carbon in construction are not easily answered but new data on timber products provides new levels of understanding.

Earlier in the year leading construction industry and built environment experts from 11 organisations demanded policy action in – what should be – an election year with embodied carbon a key concern. Big hitting organisations including the UK Green Building Council (UKGBC), The Institution of Structural Engineers, Chartered Institute of Building, UK Architects Declare, RIBA and RICS among others, joined forces to send a clear message to UK political party leaders about the need for regulation of embodied carbon emissions in construction.

Identifying and better understanding the levels of embodied and operational carbon that our built environment and construction products contain, is crucial to hitting the 2050 net zero target. When it comes to timber – the leading mainstream low carbon construction material – a new investigation of embodied carbon data for more than 95% of timber consumed in UK has just been released by Timber Development UK (TDUK). And all completely free for all to digest.

Quality carbon data

TDUK has released average carbon data for the 10 major timber product categories. This data will support architects, engineers, and other specifiers to make accurate assessments of the carbon impacts of their material choices as early in the design process as possible – when they have the greatest ability to influence them.

“Consistent and up-to-date embodied carbon data is key to making accurate design decisions,” said Michael Polack, Technical Manager for B&K Hybrid Structures. “Particularly as the embodied carbon of timber continues to further improve. At B&K Hybrid Solutions, we fully support the development of TDUK’s EPD database and weighted averages for timber products, which are particularly valuable for supporting design teams at early design stages.”

TDUK’s new independently verified ‘Embodied Carbon Data for Timber Products’ calculates weighted average A1-A4 embodied carbon data for common timber products such as softwood, engineered timber, and panel products, including and excluding sequestered carbon. More than 80 EPDs were reviewed in this comprehensive new paper. A1-A4 data is provided for 10 major timber products which means the EPD Database can be used to calculate the carbon impact of more than 95% of timber consumed in the UK. The A1-A3 data draws only from EPDs for products available in the UK, with the data weighted based on country of origin. With the addition of A4 data on transport to the UK, calculated using TDUK’s access to imports information to consider our diverse supply chain – this is the most accurate data for timber products available for whole life cycle assessments in the UK.


With one of TDUK’s core missions being to help create a low-carbon future, this data – and a paper on the methodology (which has been independently verified by Construction LCA). Charlie Law, Sustainability Director for TDUK, said: “If we are to achieve national and international targets to reach net zero carbon emissions by 2050, we need to measure, understand, and significantly reduce the embodied carbon within the buildings and infrastructure we construct.

“Environmental Product Declarations (EPDs) are key for specifiers to design low-carbon assets, helping them accurately assess the impact of their designs and material selections, but historically, limited data has been available. Only in the past few years has this begun to change. But with a continual push for more EPDs for products in construction, more data is becoming available every day – the results of major efforts made by timber suppliers. Our EPD Database capitalises on all of this data by drawing on the available independently verified EPDs for timber products to calculate weighted average A1-A4 embodied carbon data.

“All of the data, and the methodology used to create these averages, is completely independently verified – and freely available for all to download and use for their own tools and resources. We are proud to have undertaken a particularly rigorous process, and release both the data and methodology for free. This means anyone working within the built environment can benefit from this research, with complete confidence in its independence. Robust data is essential for reducing the carbon impact of construction, allowing specifiers to make informed decisions. We will be updating these figures every year as more data becomes available.”

The paper which accompanies the EPD Database figures has more information on the methodology used, data confidence levels, and includes a PDF dataset with links to EPDs, product densities, and a verification report by Jane Anderson at Construction LCA, confirming compliance with CEN/TR 15941:2010 standards.

“Having already compared these figures to some of our previous embodied carbon counts we can see a marked improvement,” said Kelly Harrison, Director, Whitby Wood. “It’s invaluable to have actual datapoints and verified, weighted average EPD information at early design stages to ensure that we make the right decisions.”

Timber policy – learning lessons

Commissioned by TDUK and written by Waugh Thistleton Architects, ‘Timber Policy’ is a comparative study of policies, across six countries, which can act as a powerful tool to support policy makers on their journey to decarbonise construction in the UK, and beyond. Timber is at the heart of transitioning to a sustainable, circular economy for the UK and many nations around the world. This study is a snapshot of a rapidly evolving movement.

“What we need to see this year is ambition turned to action,” says David Hopkins, Chief Executive of Timber Development UK. “This means forward looking policy – and politicians brave enough to create a framework which places value on low-carbon construction. Timber is the ultimate low-carbon material, and countries across the developed world have rightly recognized this – working to create comprehensive policy frameworks that support the growth of the timber industry.

“The UK Government’s roadmap is a fantastic starting point, but without more action, there is a risk the UK falls behind. We need a clear timeline for change, starting with limits on embodied carbon in buildings, which is currently unregulated. Embodied carbon can account for more than half of the emissions of a building over its lifetime - hundreds of thousands of tonnes of carbon per year - but this is currently ignored by UK politicians and policy makers.

“Our new book, commissioned by TDUK and written by Waugh Thistleton Architects, highlights the policies being put in place in a variety of countries around the world. The UK Government, if they are serious about achieving the goals of their roadmap, now need to look at what policies would work in the UK. We hope that these examples give food for thought and we can start to engage policy makers on making this happen, rather than simply relying on the market to change.”

Global imperatives

Embodied carbon is recognised by major policy influencers such as the United Nations, Royal Society and World Green Building Council, and in the UK by the likes of the Climate Change Committee and Environmental Audit Committee as crucial to overcoming climate change.

Despite a wide array of evidence and calls from these bodies to implement key policies, such as the regulation of embodied carbon, there has been a highly variable policy approach across the world. The UK, once positioned as a leader in sustainable construction using timber, now lags behind many other nations due to its regulatory environment. Timber Policy outlines how six different countries around the world are helping to support the transition to low-carbon construction.

“Working at the forefront of global timber construction and participating in extensive research with European partners, we understand first-hand the impact of government policies on sustainable, low-carbon construction.” adds Andrew Waugh, director and co-founder, Waugh Thistleton Architects. “While the UK once led the world in mass timber construction, recent years have seen a shift in global leadership. Recent assessments, such as the Climate Change Committee’s critique of the UK Government’s Carbon Budget Delivery Plan, highlight the urgent need for accelerated policy development in the UK.

“While we commend initiatives like the Timber in Construction Roadmap, our research for Timber Policy reveals that current UK efforts fall short of addressing the urgency of the climate crisis. Bold leadership, as demonstrated by progressive nations such as France, Germany, The Netherlands and Denmark, mandating limits on embodied carbon and investing in sustainable timber projects, is essential for a meaningful transition to a low-carbon future. The Roadmap sets out timelines to consider options, encourage voluntary reporting, and seek advice, after which revisions to policy will be put in place. The Timber Policy Guide shows how this process has already happened in the six example countries and policies which have already been implemented.

“Despite challenges, some progress in the UK is evident. For example, the DfE’s flagship project to standardise mass timber school fabrication underscores its commitment to innovation. Additionally, the Mass Timber Insurance Playbook and New Model Building Guides, funded by Built by Nature, a philanthropic organisation, provide invaluable resources for navigating the complexities of timber construction.

“The urgency of climate action cannot be overstated. With projections indicating a 1.5-degree increase in global temperatures by 2050 and up to 3 degrees by the end of the century, decisive steps must be taken. The Timber Policy book serves as a beacon of hope, illustrating how public-private partnerships can drive systemic change towards a sustainable future.”

The new, free to use timber EPD database fulfils a key commitment made by TDUK within the UK Government’s recent Timber in Construction Roadmap.

You can download the 2024 Embodied Carbon Data for Timber Products at: www.timberdevelopment.co.uk

You can also find a copy of Timber Policy at: www.timberdevelopment.uk/resources/timber-policy

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