Matteo Sarno and Joe Penn SBE0126

Written evidence submitted by Matteo Sarno and Joe Penn in personal capacity


Scale of the problem & Co-benefits of Embodied Carbon regulation



  1. Brief Introduction about us


1.1 Matteo Sarno has been working as a chartered architect in the UK since 2007, in large practices on buildings ranging in value from £35M to £500M. In the last year, having set up his own practice, he has been working on small domestic retrofits and extensions with a value of £200K.


1.2 Joe Penn is an architect with 5 years of experience practising in the UK. He has worked at medium-size office in both Bristol and London working in education and residential sectors. Joe studied his masters in architecture at the Royal Danish Academy in Copenhagen, where he also spent 4 months working as an architect.


1.3 The frustration in the lack of embodied carbon regulations in the UK was the main cause for Joe and Matteo to join ACAN, where they co-authored a report for politicians and policy makers on embodied carbon and have been campaigning on the subject for almost 2 years.



Executive summary


        In each and every project we work on, the lack of appropriate regulation is and has been the no.1 obstacle in designing low embodied carbon building and the use of natural materials.

        Through the introduction of carbon regulation in the construction industry a wide range of ancillary public benefits can be facilitated including: healthier streets, buildings and homes, healthier construction workers and occupants, the protection of communities and natural environments, increased biodiversity, supporting local businesses and the creation of hundreds of thousands of new jobs.


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


1.0              In our professional experience, it is very difficult to persuade clients to use timber structure, which is the most effective way to decarbonise new homes. Often clients and contractors perceive timber as more expensive or do not fully understand the properties of structural timber and are worried for instance about combustibility. This has got significantly worse since badly thought-out changes to Building Regulation Part B were introduced after the Grenfell tragedy. In many of our projects we encounter builders and structural engineers that are not interested in carbon reduction and are reluctant to change to timber because they are used to using concrete and steel and there is no regulation to encourage them to change.


1.1              Whilst there seems to be growing interest from clients and developers in structural timber systems and timber panel construction, as well as natural insulation materials, the reality is that these materials rarely get further than the design stage of a project. Housebuilders are unwilling to take on the potential risks including insurance, risks of longer lead-times and working with less familiar construction methods. Few clients are seeking to change their practices without clear financial or regulatory incentive. Unless required by local planning conditions, for-profit housebuilders which make up the majority of the UK market generally require architects & engineers design to minimum standards assuming this will keep costs down. We desperately need regulation on issues such as embodied carbon to ensure the industry decarbonises at the scale and speed required to meet national emissions targets.


1.2              The BEIS Select Committee recorded within their ‘Energy Efficiency: Building towards Net Zero’ record[1] confirmation from the house builder industry that regulation leads and limits progress:

              However, we are disappointed that we may have to wait until 2025 for homes to be built with “world-leading levels of efficiency” when the UK’s two largest housebuilders confirmed they do not require a long lead in time to deliver higher standards.328 Barratt and Persimmon said that higher standards could viably be delivered within 18 months.329 But with profit margins and shareholder returns the overriding priority for the majority of large housebuilders, they will not upgrade their standards without being required to do so by regulation. We recognise that there are some more progressive housebuilders who have indicated willingness to deliver higher standards at scale,330 but there is no commercial case to do so without a level playing field among all developers.”


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?


2.0              There are a wide variety of natural materials including wood fibre, wool, straw and earth which due to their inherent structural properties are excellent insulators and very efficient at regulating temperature. During their growth, biogenic materials capture large amounts of CO2 (sequestration), storing it throughout their lifespan. They can be used to directly replace oil and chemical based materials such as PIR insulation which often have high toxicity.


2.1              Conventional building materials made from non-renewable resources are the main source of indoor air contaminants (i.e. VOCs), whose impact can extend from indoors to outdoors and affect soil quality when disposed of at end of life.


2.2              Many natural materials grow fast and are therefore often cheap.

There are already a number of existing building products and suppliers on the market such as Warmcel, Steico, and Thermafleece.


2.3              Natural materials assist with producing buildings which are much more ’breathable’ i.e. allow water vapour to transfer through the envelope. This reduces the risk of damp, thereby improving the health of occupants and the longevity of the building itself.


2.4              Due to its strength and versatility enabling it to be a substitute for high-impact materials such as reinforced concrete and steel, structural timber in the form of CLT, Glulam or traditional framing is easily the most effective material at reducing embodied carbon rapidly at scale. Structural building elements, are the largest building elements by weight, volume and crucially embodied emissions. Timber is also a much better insulator than the standard structural materials of concrete or steel.


2.5              Timber is substantially lighter than concrete or steel, which makes it much easier to transport, improving air quality and minimises the size of foundations which helps to further reduce carbon emissions.

Earth construction can also be used to replace structural elements or thermal mass (used to regulate indoor temperatures) typically provided by concrete.


2.6              There are also a growing number of studies which demonstrate the direct positive impact on well-being[2], productivity, and learning of reducing VOCs and using timber and bio-based materials in buildings.[3] Use of natural building materials also reduces health risks of construction workers on site associated with traditional methods of construction.[4]


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

3.1              Promoting / incentivising the use of bio-based materials would support the creation of green jobs in the UK’s sustainably managed timber and bio-based materials industry. This has been explored in a standalone report on the UK’s bioeconomy by the CCC[5] and the Green Finance Institute[6]


3.2              It would also provide market incentive for the renewal of the British steel and concrete industries with manufacturers pushed to adapt to the UK’s projected carbon budget timeline[7] as designers seek out low carbon products.


3.3              By building homes with bio-based materials (i.e. timber) the Government could drastically reduce carbon emissions and construction waste (through off-site construction) as well as meeting their housing targets due to increased speed of construction. This was highlighted by the APPG for the Timber Industries in their 2019 housing report.[8]


3.4              Promoting the use of nature-based materials and products can help grow UK based SMEs


3.5              To successfully maximise this green growth opportunity, the Government should provide businesses with a clear timeline establishing how and when they need to adapt to support the net-zero carbon future. Clarity of communication, and Government transitional investment will be needed to transition unsustainable jobs in industries that require the greatest transformation - as called for by the internationally-recognised Just Transition framework.[9] For instance, there are currently 160,000 people employed in the UK plastic industry that will need to be a part of this national transition.


3.6              This sector of nature-based materials should also be seen as an opportunity for the development and leadership in material-based scientific innovation in the development of new materials. As an example, Biohm[10] and Adaptavate[11] are two examples of UK-based material companies pioneering how bio-based materials can replace current traditional, high-impact materials such as plasterboard.


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?


4.0              Planning policy at both national and local level can help significantly deter the needless demolition of buildings by incentivising extension and refurbishment, which are much more sustainable approaches (massively reducing waste, saving embodied carbon & reducing new construction emissions) than demolition and redevelopment through an independent audit.


4.1              There are strong social and economic reasons to prioritise re-use and refurbishment over demolition and new build. Retrofit has the potential to create new and higher skilled jobs in every region and community and boost existing firms (especially SMEs and their supply chains).[12]


4.2              Retaining existing buildings preserves existing communities and cultural assets, and helps to maintain diversity and equality in our neighbourhoods.


4.3              With homes responsible for 30% of total UK carbon emissions a national retrofit strategy is essential to meeting climate targets.12 Retrofitting existing homes also has the consequential benefits of reducing fuel-poverty and national fuel allowances, providing families with more disposable income and improving public health which in turn reduces strain on the NHS.


4.4              According to Defra, waste from construction, demolition and excavation accounts for upward of 60% of England’s total waste stream. Whilst some 90% of construction and demolition waste is recovered, predominantly heavy and carbon intensive to produce materials such as concrete, brick and asphalt, it is generally downcycled for use as aggregate.[13] Instead changes to planning policy and building regulations could kickstart the nascent construction materials recycling industry. Analysis by WRAP has estimated that 500,000 jobs could be created in the UK through the transition to a more resource efficient circular economy.[14]


4.5              In our experience due to low costs of standard building materials and minimal penalties for waste disposal in the UK, attention paid to reducing on-site waste is limited to where it will make substantial cost savings, except on projects where the client or planning authority insist on certification such as BREAAM or LEED. It is often cheaper to over buy on materials / cut to fit on site than spend more designing out waste or risk programmatic implications of having to reorder.


4.6              An Environmental Product Declaration (EPD) is a document used to quantifiably demonstrate the environmental performance of any product. EPDs are a crucial tool when trying to specify building products with low embodied carbon / environmental impact / VOCs and help enable Whole Life Carbon Assessments. In practice however many suppliers do not have EPDs whilst others can be unwilling to provide them. EPDs can be used as a tool to assess, regulate and promote sustainable practices and should therefore be mandated from material suppliers to inform designers and specifiers.


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?


5.0              The carbon cost of manufacture and delivery to site is an inherent part of a material's embodied carbon and it would be a misrepresentation to present data without including them.


5.1              Factoring in the carbon cost of manufacture and delivery to site would help stimulate the revival of British manufacturing as designers and contractors would be able to deliver lower-impact buildings by seeking out locally made products, which has a co-benefit of supporting up-skilling and growth in areas, for example outside London and the South- East, including the Northern Powerhouse.


5.2              Reductions in embodied carbon emissions can be used as an opportunity to grow local and national business sectors and drive investment. Wood Knowledge Wales are doing excellent work facilitating such investment in Welsh grown timber as demonstrated in their ‘Home Grown Homes Project’.[15]


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


6.0              There is insufficient legislation to ensure that sufficient quantity and quality of green infrastructure is incorporated into developments. The opportunities and benefits are not sufficiently understood by designers or developers nor is green infrastructure prioritised by local authorities. The practice of successfully using nature to provide climate resilience is frustratingly limited: i.e. using nature to form protection against flooding, to reduce the heat island effect etc. The covid-19 pandemic has also heightened our awareness of the importance of high quality greenspaces for our physical and mental health. Implementation of green infrastructure provides a powerful tool for tackling issues of health[16] and climate resilience in a high impact and cost affect manner.


6.1              The Greater London Authority’s new London Plan contains a new policy for demanding onerous Urban Greening Factors across development sites. This has been introduced to quantitatively drive net urban greening across London due to its acknowledged benefits for reducing the urban heat island effect, improving air quality, strengthening biodiversity, and biophilic benefits for residents and inhabitants. As urban areas grow nationally, deploying similar policies will be vital to mitigate the unhealthy and damaging impacts from traditional urban development.


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

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


7.0              The main reason we see demolition and rebuild being mainstream instead of reuse and refurbishment is due to the associated development costs, in part driven by the disproportionate application of VAT. As called for by the UKGBC and RIBA amongst others, The government should make changes to Building Regulations, planning policy, procurement for all publicly funded projects, and amend tax rates[17] immediately to incentivise repair, maintenance and retrofit.


7.1              Dependent on building type, embodied carbon can account for upto 75% of a buildings life cycle carbon emissions. Given this huge contribution we would suggest that all projects should have to demonstrate the carbon cost as part of the viability assessment of retrofit prior to being granted permission for demolition.


May 2021

[1] BEIS Select Committee (2019) ‘6 New Build Properties’ Link




[5] Climate Change Committee (2018) “Biomass in a low carbon economy”, accessed 31 Jan 21,

[6] Green finance Institute (2020) “Stimulus actions for a greener and more resilient property sector”,

accessed 31 Jan 21,


[7] Committee on Climate Change (2020) “The Sixth Carbon Budget - Sector Summary

Manufacturing and Construction”, accessed 31 Jan 21,


[8] All Party Parliamentary Group for the Timber Industries (2019), “How the timber industries can

help solve the housing crisis”, accessed 29 Jan 21, report downloadable at


[9] Climate Justice Alliance “Just Transition - A Framework for Change”, accessed 30 Jan 21,



[12] Construction Leadership Council ‘Greening Our Existing Homes’

[13] Construction Leadership Council - ‘Zero Avoidable Waste in Construction’

[14] Morgan, J. and Mitchell, P. for Wrap and Green Alliance (2015) “Employment and the circular economy. Job creation in a more resource efficient Britain” accessed 31 Jan 21,



[16] www./