Green Alliance SBE0135

Written evidence submitted by Green Alliance


About Green Alliance

Green Alliance is an independent think tank and charity focused on ambitious leadership for the environment. Since 1979, we have been working with the most influential leaders in business, NGOs and politics to accelerate political action and create transformative policy for a green and prosperous UK.

We have responded to the sections within this call for evidence that are most relevant to projects that have been, or are being undertaken, at Green Alliance, which includes transitioning the built environment towards net zero and resource efficiency.


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

Embodied carbon in buildings is so far largely unaddressed, despite accounting for a significant share of an average building’s climate impact[1] and one that will grow as operational emissions are reduced.

Action has been limited to only a few local authorities and voluntary initiatives. For example, the new London Plan demands that developers produce circular economy statements and whole life carbon assessment for projects referable to the mayor.[2]

We have argued that the Future Homes Standard (FHS) should set requirements for tackling embodied carbon of new homes. However, not only is the FHS delayed to 2025, which means hundreds of thousands of homes are likely to be built to lower standards (placing the burden and cost of home efficiency improvements on the future owners of those homes), but the standard also fails to consider embodied carbon.  This is a major omission, since embodied emissions from construction for residential blocks can account for approximately half of the total emissions over the building’s life. And, with a large number of new homes expected to be built over the coming years to meet the government’s commitments to housebuilding, it’s a missed opportunity to promote low carbon construction and reduce emissions upfront.

Furthermore, it is important to note that upgrading UK building stock will reduce emissions, especially from inefficient solid wall properties, while limiting the need to demolish and construct new buildings. In most cases, retrofitting reduces operational emissions and helps to keep embodied carbon low. The largest net savings are achieved through deep retrofit interventions. For example, whole retrofit of a typical pre-1930s building (which accounts for nearly a third of UK buildings) would cut overall operational and embodied emissions by nearly 80 per cent over a sixty year lifespan, compared to the 40 per cent carbon reduction that could be achieved by incremental retrofit measures.[3] Deep retrofit can also achieve lower overall emissions compared to the average new building today, with just over a quarter of the embodied carbon.[4]

For these reasons, it’s disappointing that, in addition to the lack of policy and regulatory drivers to address embodied carbon, government action to promote building retrofit and tackle operational emissions is still falling short. Considering new decarbonisation policies that have been announced since the beginning of 2020, the buildings sector is not on track to cut (operational) emissions sufficiently to be aligned with the net zero pathway during the 2028-32 fifth carbon budget period. A combination of funding and regulations announced since January 2020 will help to make only about a third of the emissions savings needed.

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?

A range of material choices can help reduce embodied carbon in buildings. These include greater reuse of materials (including through upgrading and refurbishing buildings, as opposed to demolishing and re-building), increased use of recycled content as well as opting for low carbon virgin materials, such as timber, in place of high carbon alternatives such as steel and cement. Reuse would be especially beneficial in the case of steel, a material which is very carbon intensive, and for which there is evidence of a significant untapped potential: currently, only around five per cent of structural steel is reused, although up to 50 per cent could be.[5]

A number of examples of existing buildings show that substantial reductions in embodied carbon can be achieved through these measures. For example, the Enterprise Centre at the University of East Anglia has a quarter of the emissions of a conventional university building, thanks to the use of low carbon materials. And the retrofit of the University of Cambridge’s David Attenborough Building saved 82 per cent of the embodied carbon by being refurbished rather than demolished and rebuilt.[6]

Importantly, promoting low carbon construction materials would also provide a market for low carbon primary steel, as the UK transitions to near zero steel production (in line with the CCC’s recommendation for the sixth carbon budget). Hydrogen-based production is a promising route to decarbonising primary steel but will require a concerted approach, including investment in a trial for hydrogen based production alongside demand side measures such as procurement and product standards.

New construction methods can also support reduction in embodied carbon. Offsite construction is well suited for low carbon building materials, such as cross laminated timber, as well as modular design, which can support greater building adaptability and reuse. Built in a factory, this type of construction can benefit more from advanced technologies than traditional approaches. It helps to lower energy and resource inputs, and cut waste by around half compared to conventional construction. Furthermore, thanks to standardisation and economies of scale, it also helps to lower costs and scale up deployment.[7]

Finally, there is the opportunity to leverage new technologies for better assessment of the environmental impact of materials. Some companies already make use of Building Information Modelling (BIM) to support better project planning and delivery. This is a platform used to manage building design and project data in a digital format. While applications have so far taken a static view of buildings, the use of BIM, or similar digital twin tools, could be extended to understand a building’s whole lifespan, avoiding design that locks in poor adaptability and limits reuse, and supporting better tracking of materials. For example, sensor tags linked to ‘material passports’ (digital records of component characteristics) provide information about availability and condition. Information from material passports and BIM can be combined to facilitate the recovery and repurposing of materials. It can also help to understand their value, strengthening the business case for reuse, and support the development of material exchange platforms.

Overall, better use of materials in the construction sector (including reduction in material input through better design, greater reuse, and replacing high carbon materials with lower carbon alternatives) could reduce greenhouse gas emissions by 79 MtCO2e between 2023 and 2032.[8]

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

In Less in, more out, we show that resource efficiency in the construction sector offers the greatest opportunity to cut carbon emissions, with potential to reduce them by 79 MtCO2e between 2023 and 2032, according to research by CIEMAP. Of the measures to reduce embodied emissions, the one with the biggest impact is substituting low carbon building materials for high carbon materials. This could lead to carbon savings totalling 48 MtCO2e (20 MtCO2e in the fourth carbon budget and 28 MtCO2e in the fifth).[9] The Enterprise Centre at the University of East Anglia, where renewable materials account for nearly half of the building by volume, shows what this approach can achieve. The use of natural and renewable materials – including timber, straw, hemp and clay – means the building’s embodied carbon is only a quarter of the footprint of a typical university building.

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?

We believe that every element of the planning system should be in line with net zero, and the upcoming Planning Bill must ensure that net-zero and the environment is at the centre of all future developments. There should be a whole life approach to building, that designs differently (low/zero carbon, low material input, more reuse, adaptable and reusable structures), uses buildings better, and maximises reuse.[10]

As emphasised in our answer to the first question, the Future Homes Standard (FHS) must ensure that all new buildings which are developed are in line with net-zero, and that assessments of buildings look at the whole life carbon impacts. As part of the FHS, all developments should assess and disclose whole life carbon impacts, with the introduction of targets for reductions in whole life carbon, to be applied to larger developments first and ultimately to all developments by 2030.[11]

Furthermore, while it is welcome that government has decided to allow local authorities to set higher requirements for building efficiency and standards than the national standards, local authorities must also be provided with the support, skills and funding to be able to do so. This will enable local authorities to contribute to the national net-zero goal and deliver on their climate emergency declarations.

Crucially, low carbon transport is also core to a sustainable built environment, and the planning system provides a route to ensure all of these aspects are considered in a joined up fashion. We recommend that the planning reforms require for all new development to be located and designed to facilitate zero transport emissions, and must only be located where this can be supported. Transport issues must be considered from the earliest stages of plan making, to ensure that the chosen location is either well connected or has the ability to be well connected, and that the transport infrastructure needed is available from day one of residency to avoid early residents being forced to purchase a car.

This would support delivery of the policies being rolled out by the Department for Transport through Gear Change and through the upcoming Transport Decarbonisation Plan. As the Climate Change Committee highlighted in its recent Sixth Carbon Budget report, the UK must see total car miles fall by 9 per cent by 2035, and 34 percent by 2050. Improving access to sustainable modes of transport will also support the government’s need to reduce illegal levels of air pollution by cutting down on nitrogen oxides from vehicle emissions. In order for this to be achieved, the planning system must work in a way which stops a reliance on cars, and prioritises public transport, walking and cycling infrastructure wherever possible.

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

Whole life carbon assessment methodologies are already available, as outlined by Giesekam and Pomponi (2018), and should help overcome common concerns surrounding data quality and scope for greater standardisation of assessment procedures. [12] The government should set out a roadmap for mandatory whole life carbon reporting and reduction targets for construction projects.

Such requirements already exist in other countries. For example, the Netherlands requires developers to report on the embodied carbon of developments larger than 100m2 since 2013. It has recently introduced regulation to set a maximum environmental footprint for buildings to accelerate emissions reductions.

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?

The UK should aim to have as comprehensive an assessment of lifecycle impacts as possible, to ensure action to tackle carbon in buildings does not lead to more emissions generated elsewhere in the system. This would stimulate a move towards lower carbon materials and construction processes, since offsite construction is well suited for low carbon building materials, such as cross laminated timber, as well as modular design, which can support greater building adaptability and reuse.[13]

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

Almost all the UK’s 29 million homes will need to be retrofitted for energy efficiency and low carbon heat if the country is to meet climate targets by 2050, requiring an ambitious new approach.[14]

Demolishing buildings squanders the carbon emissions generated in their construction. This is especially problematic for residential buildings, where emissions associated with their construction can account for over half of their total climate impact over their lifecycle.[15] This share is likely to increase as emissions from heating and powering buildings are reduced because of renewable energy and efficiency measures. Demolition also creates a lot of waste: the construction, demolition and excavation sector are responsible for a substantial 62 per cent of the total waste generated in the UK.[16]

Image taken from Added value’ (Green Alliance, 2020)

As we outline in our answer to the first question, retrofitting and upgrading UK building stock will reduce emissions while limiting the need to demolish and construct new buildings, helping to keep embodied carbon low, and should therefore be prioritised.

Encouraging more urban renovation could also help with the housing crisis. Our research shows that long term vacant properties could fulfil between 14 and 46 per cent of new housing needs to 2030 across different metropolitan areas.[17]

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

As mentioned in our previous response, the government should also set out a roadmap for mandatory whole life carbon assessment and reduction targets for construction projects. As part of their assessment, developers should consider options such as refurbishment (where relevant), alongside demolition and new build. Such requirements should apply immediately for larger developments, and apply to all developments by 2030 at the latest.

Furthermore, government should urgently set out a robust and comprehensive homes decarbonisation policy that puts in place long term regulations and funding for incentives. While there have been some positive steps in the recent months, including the new fuel poverty strategy, the new regulations for non-domestic rented properties and the Social Housing Decarbonisation Fund Demonstrator, more is needed to ensure a comprehensive upgrade of the UK’s building stock. Building on the hard lessons of the now scrapped Green Homes Grant, the government should put in place a strategy that kickstarts the upgrade of the UK’s inefficient homes over the next decade. This must include: £2.3bn additional funding per year to the end of this parliament, to support energy efficiency and heat decarbonisation; regulation on minimum energy efficiency standards of all tenures of housing, so that all homes are rated EPC Band C or above by 2030; setting out attractive incentives to upgrade homes through grants, financial mechanisms like green mortgages; a dedicated programme to promote innovation in whole building retrofit, with £250 million additional funding allocated on a commit and review basis to scale up the supply chain and help bring down costs of installation; and bringing VAT on renovation and low carbon installations in line with zero rate VAT on new build.[18],[19] This will have multiple benefits. A long term home decarbonisation programme could create 190,000 jobs, reduce UK household energy expenditure by £7.5 billion a year, alleviate pressure on the NHS by preventing excess winter deaths and reduce inequality in and between regions.[20]

In Added Value, we argue that VAT currently encourages the demolition of useful buildings. New build is zero-rated for VAT while most renovation and repairs are charged 20 per cent VAT, which favours demolition over restoration. Consequently, 50,000 buildings are knocked down every year, and the number of long term vacant buildings in England has risen over the past three years in a row, reaching nearly 226,000. Zero rating VAT for repair and renovation would contribute to a green recovery, by providing an economic stimulus of over £15 billion, while creating nearly 100,000 extra jobs in construction and the wider economy, while only modestly impacting Treasury revenue, with net losses in the first year totalling around £920 million, according to Experian. Support for this policy comes from a number of influential bodies, including the Home Builders Federation, Historic England and the Architects’ Journal, as well as two thirds of builders, who think it would help boost their businesses.[21]

In Smart Building, we argue that digital technology can help with better use, and upgrading, of building. Examples include predictive maintenance, sensors used to improve utility, as well as the data enabled mass customisation of deep efficiency retrofit solutions, such as those pioneered by Energiesprong. However, while these new technologies could significantly enable emission reductions, progress to adopt them has been limited. This is partly because the construction industry has a lower level of digital adoption compared to other sectors.[22],[23] The strong focus on new build has also limited efforts to use digital solutions to futureproof existing buildings and support reuse. And not much has been done to tackle embodied carbon in buildings. Most applications are focused on the early stages of construction, while opportunities during use and for repurposing are being overlooked.[24] New policy is needed to ensure that industry can capitalise on digital solutions to futureproof UK buildings, and build expertise and supply chains; more detail on our policy recommendations is provided in the report.


May 2021

[1] Embodied emissions from construction for office buildings accounts for over a third of total emissions over its lifecycle, while for residential blocks and warehouses, it accounts for approximately half (Green Alliance, 2020, Added value)

[2] Greater London Authority, 2019, The London Plan (intend to publish version)

[3] Department for Environment, Food and Rural Affairs (Defra), BaEST, 2008, BRE HOUSING energy analysis focus report: a study of hard to treat homes using the English house condition survey – Part I: dwelling and household characteristics of hard to treat homes, cited in A Moncaster, et al, 2013, Retrofitting solid wall buildings: energy and carbon costs and savings.

[4] building_methodology.php

[5]   D Cooper and JM Allwood, 2012, ‘Reusing steel and aluminium components at end of product life’, Environmental Science and Technology, 46, 10,334-10,340; J Cullen, 7 June 2016, Steel reuse in construction, presentation

[6], 2017-2020 Progress: provisions for greater use of steel structures, ‘Factsheet no.2: SEGRO warehouse, Slough, UK’; Green Alliance, 2018, Less in more out; CIBSE Journal, December 2016, ‘Creature comforts – David Attenborough Building’.

[7] Science and Technology Select Committee, 2018, Off-site manufacture for construction: Building for change. Oral and Written evidence; Mayor of London, PRiSM,

[8] Green Alliance, 2018, Less in, more out

[9] CIEMAP, 2018, Reducing carbon in construction: a whole life approach

[10] Green Alliance, 2020, Smart building

[11] UK Green Building Council, February 2020. UKGBC Response to MHCLG Consultation on the Future Homes Standard.

[12] Giesekam and Pomponi, 2018, Embodied carbon dioxide assessment in buildings: guidance and gaps

[13] Green Alliance, 2020, Smart Building

[14] Green Alliance, 2021, Net zero policy tracker

[15] Royal Institute of Chartered Surveyors (RICS), 2017, Whole life carbon assessment for the built environment.

[16] Department for Environment, Food and Rural Affairs, March 2020, UK statistics on waste

[17] Green Alliance, 2020, Smart building

[18] Green Alliance, 2019, Reinventing retrofit

[19] Green Alliance, 2021, Net zero policy tracker: April 2021 update

[20] Energy Efficiency Infrastructure Group, 2020, From the Green Homes Grant towards a resilient net zero economy

[21] O Wainwright, 13 January 2020, ‘The case for ... never demolishing another building’, The Guardian; Building Better, Building Beautiful Commission, 2020, op cit; Historic England, 2020, There’s no place like old homes: re-use and recycle to reduce carbon; Federation of Master Builders, 9 March 2020, ‘Two-thirds of builders ask Chancellor to cut VAT’,

[22] F Barbosa, 2017, Reinventing construction: a route to higher productivity

[23] M Peters et al, 2017, Buildings as material banks and the need for innovative business models

[24] Cambridge Architectural Research Ltd, 2018, Defining the research agenda and research landscape for Digital Built Britain: digital tools in the creation and through-life management of built assets; see uk/smart_building_ methodology.php