Timber Development UK, Timber Research and Development Association, Timber Trade Federation              SBE0042

Written evidence from Timber Development UK, Timber Research and Development Association, and the Timber Trade Federation





To what extent have the Climate Change Committee’s recommendations on decarbonising the structural fabric of new homes been met?

  1. The Government has not met the Climate Change Committee’s (CCC) recommendations to decarbonise the structural fabric of new homes; neither MHCLG or BEIS have developed or implemented any policies which incentivise the use of low carbon materials to reduce the embodied carbon impact of construction. Currently only operational carbon emissions are regulated for within Part L of The Building Regulations.


1.1. The CCC’s recommendation to grow the use of wood in construction as a low embodied carbon alternative has been repeated in multiple reports, including Biomass in a low carbon economy (2018), UK housing: Fit for the future? (2019), and most recently The Sixth Carbon Budget: The UKs path to Net Zero (2020).


1.2. When policy makers have sought to address the emissions from our built environment there has been a narrow focus; limited to operational carbon - which arise from a building in use, such as the energy used for heating our homes. Embodied carbon, which in modern buildings may form up to 75% of the emissions of a building over its lifetime, are currently unregulated.


1.3. In the absence of national policy leadership there have been industry pledges, including RIBA 2030, Declare movements from Architectural and Engineering practices, and devolved administrations and councils making greater efforts to reduce embodied carbon in new build construction.


1.4. Some examples include:


(a)    Hackney Council Wood First Policy: Hackney Council adopted a preference for sustainable timber construction in 2012, which helped transform the district into world leaders in the use of engineered woods such as Cross-Laminated Timber (CLT). 

(b)    Powys County Council Wood Encouragement Policy: Powys County Council adopted a wood encouragement policy in 2017 to reduce carbon and support rural and regional employment and economic development.

(c)    Welsh Government Affordable Homes Programme: Welsh Government have stated that all affordable homes built in Wales from 2022 must be timber frame. To achieve this, they have set up a consortium of 11 councils and 14 timber frame manufacturers.

(d)    Greater London Authority’s London Plan 2021: Greater London Authority under Policy SI 2 has mandated that all development proposals referable to the Mayor must include a Whole-Life-Cycle Carbon Assessment.


1.5. If the Government is to meet the recommendations of the Climate Change Committee, embodied carbon emissions must be tackled on a national level, and the Government must create and embrace a consistent position on the use of wood in construction. This should include within fire safety regulations, to ensure the science is followed with regard to the performance of timber elements within a building’s structural frame.


1.6. The current ban on combustible materials within the external walls of buildings, while targeted towards mid to high-rise residential buildings, is adversely affecting even long-standing forms of timber construction – such as closed panel timber frame – at all levels, as well as stifling innovation in the use of timber in other building types including high rise offices. We would refer you to the work of the CTI Fire Hub and their response to the most recent consultation on the ban which lays out the evidence for the safe use of timber in building structures.


1.7. Members of Timber Development UK, which encompasses the entire timber supply chain, from forest through to architects and specifiers, responded overwhelmingly during our survey around this inquiry said there has been no progress on the CCC’s recommendations to reduce embodied carbon from construction, and to increase the use of wood in construction. We expect this view will be shared right across the industry.

How can materials be employed to reduce the carbon impact of new buildings, including efficient heating and cooling, and which materials are most effective at reducing embodied carbon?

  1. The greatest opportunity for reducing carbon emissions from the built environment, for all aspects of a building, including through materials, is within the initial design and planning process.[1] Carbon emissions need to be prioritised from the beginning of the project, both in terms of creating a building which will provide operational efficiency without the need for expensive refurbishment, and the effective use of the mainstream building material with the lowest embodied carbon – timber.


2.1. Despite the recognition of timber by industry as a high-performance, low-carbon material,[2] when compared to countries such as Germany and Finland, the UK has far lower consumption (with the exception of Scotland, where 83% of new builds are timber frame). [3] This shows there is scope for the use of wood to grow in the UK, and for a shift away from the relatively high consumption of cement, a material responsible for approximately 8% of total global emissions, (a greater share than any country other than China or the US).[4]


2.2. When wood is used in construction it helps reduce the carbon impacts of new buildings in two ways; (1) it acts as a form of carbon capture and storage, with carbon dioxide sequestered by trees and then stored for the lifetime of the building product, and (2) it can be used to displace carbon-intensive materials such as cement and steel.


2.3. Using timber frames rather than masonry can reduce carbon embodied emissions by around 20% per building. When CLT is chosen in place of concrete structures the effect is even greater, with carbon embodied emissions reduced by around 60%.[5]


2.4. By combining an increase in the use of wood with more efficient approaches to construction, primarily through the use of Modern Methods of Construction (MMC), whether mass timber or timber frame, carbon emissions can be reduced even further through a 90% reduction in waste,[6] fewer deliveries to site, and up to 30% quicker build times.


2.5. Resource efficiency through the better design, deployment, and use of materials, and the placement of these materials into the circular economy, is crucial to reducing waste – as construction accounts for more than half of material use and waste generation in the UKand the carbon emissions which come as result of this wastage.[7] As a natural, renewable and recyclable material, timber already fits into a circular economy model.[8]


2.6. Meanwhile the slow adoption of stronger efficiency standards with the Future Homes Standard, which will not be put in place until 2025, means homes are currently being built which will soon require a costly refit. The failure to embrace these policies earlier, including the abandonment of the Zero Carbon Homes policy in 2018, have already cost the taxpayer millions of pounds.[9]


2.7. Policy makers should seek to apply the lessons from this earlier failure by seeking to accelerate and embrace low-carbon construction, and avoid being dissuaded by lobbyists wishing to maintain BAU approaches. There is existing technology and materials, such as Closed Panel Timber Frame, Cross-Laminated Timber (CLT), Laminated Veneer Lumber (LVL), which are widespread, available, and scalable for improving both operational and embodied carbon efficiency; as these materials systems can also embrace aFabric-First’ and Passivhaus approach to construction.


2.8. A strong example of how timber and existing technologies can help reduce embodied carbon emissions now comes from the 2019 Stirling Prize winner, Goldsmith Street, a social housing project, which uses timber frame, and is currently the largest Passivhaus scheme in the UK.[10]


2.9. In addition to the clear performance advantages of building with timber, there are many health benefits linked to the use of wood in buildings, with research showing wood can reduce stress, lower blood pressure and heartrate, improve moods, lift productivity, strengthen immune systems, and improve air quality.[11]


2.10.         As a ‘breathable material’, timber also lends itself to a changing climate by allowing the passage of water for a healthier indoor environment. Given the projected effects of climate change on the UK,[12] this breathability is important for insulation materials; and can be found in wood-fibre insulation; a product which is used much more widely in Europe.

What role can nature-based materials play in achieving the Government’s net zero ambition?

  1. Nature based materials have an essential role to play in achieving the Government’s net zero ambition. This was recognised by Government in the Industrial decarbonisation strategy (2021), which found resource efficiency and substitution measures could save 9 MtCO2e per annum within the UK by 2050, including through timber and the reuse of construction materials.


3.1. The role of wood in construction was also recognised by the Climate Change Committee in UK Housing; Fit for the future when they stated that increasing the number of new homes built in the UK each year using timber frame construction systems from around 50,000 to 270,000 annually could triple the amount of carbon stored in UK homes to 3 Mt every year.


3.2. Another advantage of increasing the use of wood is the incentivisation of tree planting in the UK by providing a compelling argument for converting underutilised tracts of land. Clear economic, social, and environmental benefits are connected to tree planting, including employment, improving air quality, preventing floods, and of course capturing residual carbon emissions.

What role can the planning system, permitted development and building regulations play in delivering a sustainable built environment? How can these policies incentivise developers to use low carbon materials and sustainable design?

  1. These three elements; the planning system, permitted development and building regulations, play an essential role in creating a level playing field for businesses to deliver a more sustainable built environment. All these elements must seamlessly work together to create transparency, and lend weight to, the carbon cost of new buildings; as opposed to a pervasive current sole focus on finance.


4.1. As it stands, a lack of nationally mandated reporting policies for embodied carbon, or pathway towards net zero construction, allows firms to completely ignore this form of carbon emissions. Responsible firms which seek to consider the full cost of construction, and include embodied carbon emissions, may face a competitive disadvantage in the current regulatory environment.


4.2. There are select examples of local authorities, professional associations and practices which are leading the way when it comes to low-carbon, affordable construction, amidst relatively low but increasing customer demand. However, creating the level of change required to achieve net zero construction in line with targets will require nationally mandated action from the Government.


4.3. If the UK is to achieve a 78% greenhouse gas emissions reduction by 2035 compared with 1990 levels, there must be policy action now within construction – and these policies must be carried through to achieve their intended purpose. The dismissal of previous regulatory attempts by Government has unfortunately set the UK back more than half a decade.


4.4. A sensible and realistic set of policies has been put forward by the independent Architects Climate Action Network (ACAN) in their report ‘Regulate Embodied Carbon’, whose findings, pathway and policy recommendations we endorse to aid in addressing the existing regulatory gap which surround embodied carbon in the UK.

What methods account for embodied carbon in buildings and how can this be consistently applied across the sector?

  1. The method for accounting for embodied carbon emissions in construction works is laid out inBS EN 15978 Sustainability of construction works. Assessment of environmental performance of buildings. Calculation method.’


5.1. RICS professional statement onWhole life carbon assessment for the built environment provides requirements and supporting guidance for conducting whole life carbon assessments for construction projects in line with EN15978 as well as a focus on the interpretation and practical implementation of the EN 15978 methodology. This should be adopted as the nationally agreed methodology for measuring embodied carbon emissions.


5.2. The scope of application of the standard should however be specified as a ‘Whole life carbon assessment’ which would include the embodied and operational emissions of a project (A1-A5, B1-B7, and C1-C4). The RICS professional statement on Whole life carbon assessment for the built environment states that ‘As a minimum, a whole life carbon assessment must be carried out before the commencement of the technical design (RIBA Stage 4 or equivalent)’.


5.3. The LETI Climate Emergency Design Guide’ and the ACAN Regulate Embodied Carbon Report’ also recommend the use of the RICS professional statement on Whole life carbon assessment for the built environment.

Should the embodied carbon impact of alternative building materials take into account the carbon cost of manufacture and delivery to site, enabling customers to assess the relative impact of imported versus domestically sourced materials?

  1. Embodied carbon impact should account for the cost of manufacture and delivery to site in accordance with ‘BS EN 15978 Sustainability of construction works. Assessment of environmental performance of buildings. Calculation method.’ However, the origin of a building material is not the primary source of these carbon emissions; rather it comes from extraction and manufacturing. For example, timber imported from Sweden even after manufacturing, shipping, transport to site, and installation, will have sequestered more carbon dioxide than is released during this process.


6.1. This is demonstrated with the 10-story carbon neutral apartment complex in London’s Dalston, Dalston Works, by architecture firm Waugh Thistleton using Cross-Laminated Timber. The use of wood in place of concrete and steel for this building type allows the building to be carbon negative for the first few years of its use, when considering the carbon sequestered. Using a timber frame allowed the building to have 50 per cent less embodied carbon dioxide than a traditional concrete frame. It also locked in 2,600 tonnes of CO2.[13]

How well is green infrastructure being incorporated into building design and developments to achieve climate resilience and other benefits?

  1. Members of Timber Development UK surveyed for this inquiry responded in unison that green infrastructure is being poorly implemented on scale. Green infrastructure is being seen is in smaller scale, specialist building initiatives, and is being promoted by private individuals with an interest in the area, however larger companies have not shown the same level of interest, and developments remain centred on the concept of occupiers owning non-electrified cars, which does not fit with the required carbon reduction.

How should we take into account the use of materials to minimise carbon footprint, such as use of water harvesting from the roof, grey water circulation, porous surfaces for hardstanding, energy generation systems such as solar panels?

  1. We would support the use of products that reduce the carbon footprint of a building, where they are the most efficient solution.

How should re-use and refurbishment of buildings be balanced with new developments?

  1. Re-use and refurbishment should be the first choice for the construction industry, and remain so, unless it can be clearly demonstrated that a new build is a more pragmatic option for a building site.


9.1. Recently the UK Green Building Council have been working to create a clearer understanding of the decision-making process around the re-use or demolition of buildings. What is clear from their research so far, is that there is no static definition for what makes a building obsolete; instead, this is determined by a wide range of factors such as safety, cost, and site utilisation.[14]


9.2. The UK Green Building Council released ‘Circular Economy Implementation Packs for Products as a Service and Reuse’ to help guide teams around the difficult decisions they may face in this area. However, there is likely a need for statutory guidance in this area around when a building can be demolished; including on the possible release of carbon emissions from these actions.


9.3. Timber can play an important part in the redevelopment of existing buildings, as lightweight timber structures can be placed on top of existing structures to increase floor area and land utilisation.

What can the Government do to incentivise more repair, maintenance and retrofit of existing buildings?

  1. As a start the Government should seek to incentivise reuse by embracing recommendations from the UK Green Building Council including:

         Reducing the 20% VAT rate for refurbishments so it is on par with new builds or lower

         Faster planning application processing for projects including reuse at significant scales

         Consistent definitions and rules across councils and governments.[15]


10.1.         On a broader level, to retain the embodied carbon stored within existing assets, the Government will need to support a widespread cultural change within planning and in construction around re-use; both from the development of further guidance and training, and leadership on a national scale.


10.2.         The Construction Leadership Council (CLC) National Retrofit Strategy’ provides a clear pathway, actions and deliverables to level up the market and workforce. Projections from the CLC show a £5.3bn investment over the next four years is needed to place UK on the pathway, while bringing exponential benefits including £12.4bn in revenue, and avoiding 2.53Mt of CO2 emissions.


10.3.         Key to the success of their four-phase plan is leadership and communication, including the launch of a Retrofit Delivery Agency, the adoption of ‘fabric-first’ standards, as developed by the Passive House Institute, financial support such as grants, low interest loans, and green mortgages, supply chain partnerships, training and accreditation, creating customer demand, a compliance and quality regime, and further research and innovation.


10.4.         The Climate Change Committee has repeatedly stressed that the widespread deployment of energy efficiency measures across the UK’s building stock is key to any credible and cost-effective strategy to reach net zero.[16] In the wake of the dismissal of the Green Homes Grant programme, the strong actions recommended by the CLC are more important than ever for restoring trust in the ability of the UK to deliver such a programme, and to meet emissions reduction targets.


May 2021

[1] Bringing Embodied Carbon Upfront, World Green Building Council, 2019, p. 21

[2] Modern Methods of Construction, Royal Institute of Chartered Surveyors, 2018, p. 32

[3]The contribution of wood-based construction materials for leveraging a low carbon building sector in Europe”, by Hildebrandt, et al, 2017, Sustainable Cities and Society, 34, p. 405-418.

[4] Q&A: Why cement emissions matter for climate change, Carbon Brief, (accessed 10 May 2020)

[5] Wood in Construction in the UK: An Analysis of Carbon Abatement Potential, Dr Morwenna Spear et al, (February 2019) (accessed 10 May 2021).

[6] Waste Reduction Potential of Offsite Volumetric Construction, Waste & Resources Action Program (WRAP), (accessed 3 July 2019).

[7] Circular economy guidance for construction clients, UK Green Building Council, 2019

[8] Wood: Building the bio-economy, CEI-Bois, 2020.

[9] Energy efficiency: building towards net zero”, BEIS Committee, 2019, Chapter 6 New Build Properties.

[10] Case Study: Goldsmith Street, Mikhail Riches, 2019.

[11] White paper: 10 reasons why wooden buildings are good for you, Storaenso, 2021

[12] SPAB Building Performance Survey, SPAB, 2016.

[13] Case Study: Dalston Works, Waugh Thistleton, (last accessed 10 May 2021)

[14] DEEP DIVE: The choice between demolition or reuse: developer insights, UK Green Building Council, 2021

[15] UKGBC Circular Economy Policy Asks, UK Green Building Council, 2020

[16] Energy efficiency: building towards net zero”, BEIS Committee, 2019, Chapter 6 New Build Properties.