Centre for Alternative Technology SBE0068

Written evidence submitted by the Centre for Alternative Technology

Submission prepared by:

Louise Halestrap MPhil (Graduate School of the environment- Senior Lecturer in Sustainability and Adaptation), CAT.

Tim Coleridge RIBA, Chartered Architect (Graduate School of the environment- Programme Leader and Senior Lecturer in Sustainability and Adaptation)

Dr Alan Owen Chartered Engineer (Graduate School of the environment- Senior Lecturer in Sustainability and Energy Demand Management)

Paul Allen (Zero Carbon Hub)

Dr Anthony Hurford (Zero Carbon Hub)

Sarah Jenkinson- Head of Policy and communications

Peter Tyldesley CEO

CAT’s Vision is a sustainable future for all humanity as part of a thriving natural world.

CAT’s Mission is to inspire, inform and enable humanity to respond to the climate and biodiversity emergency.

Solutions to the climate and biodiversity emergency

The world must reach net zero greenhouse gas emissions by mid-century if we are to avoid dangerous climate breakdown. The earlier this is achieved, the greater our chance of limiting global temperature rise to near 1.5°C.

At the same time we need to adapt infrastructure and ways of life to reduce the impacts of now unavoidable levels of climate change, and we must address the widespread destruction of ecosystems and biodiversity loss.

CAT’s unique role

With nearly 50 years’ experience in environmental solutions, CAT has a unique role to play. Our strategy outlines the key ways in which we use our collective knowledge, networks and resources to help fulfil CAT’s mission to inspire, inform and enable humanity to respond to the climate and biodiversity emergency.

Zero Carbon Britain Hub and Innovation Lab

Our Zero Carbon Britain Hub and Innovation Lab works with councils, communities and organisations, helping build their capacity to implement solutions, create systemic change and increase resilience to climate change. We work with partners across the UK to influence government policy in support of the transition to zero carbon.

Strategic Plan

Inspiration, training and education

Over the next few years, CAT’s work will focus on providing inspiration, training and education in positive solutions to accelerate the shift to net zero greenhouse gas emissions.

Our ambitious plans include a reimagining and redevelopment of the CAT eco centre, with a new and updated immersive visitor experience. A new sustainable skills hub will allow many more people to access the skills and knowledge to help create a zero carbon future, and we will continue to develop and invest in our innovative postgraduate courses.

Alongside this, we have plans to rapidly scale up our outreach work to deliver CAT’s message and learning experiences to a much wider digital audience.

Investing in the organisation

Crucial to the success of these plans is investment in the organisation – building financial resilience, capacity and capability, including a proactive push to enhance diversity and inclusion at all levels within the organisation and amongst our audiences.

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


Include Low Embodied energy materials:

The CCC have focussed on operational carbon (in use) only- this is a start. But, in order to reach our targets in this climate and ecological emergency, it is imperative that low impact (both for Carbon and biodiversity) materials are used to get us nearer to a real ‘net zero’. The Sixth Carbon Budget refers to heating energy sources rather than materials production. Insulation is mentioned only generically not by type and therefore the embodied energy, wider environmental impacts of production and breathability between types is not recognised. In this way it is clear de-carbonising building fabric refers only to energy in-use and not in construction or retrofit.


According to recent EPC data sales and rentals of earth and timber based homes are a small but important part of the UK housing stock, the majority of which are more than a hundred years old proving that some of the lowest carbon buildings are also long-lasting. Most pre 1940 homes have some lime/earth mortars and are innately ‘breathable’ in that they allow moisture vapour to pass through the walls and disperse harmlessly from the surface .


However while the CCC’s recommendations do include measures to insulate and retrofit in a very general way they do not address how to ensure these breathable buildings are not damaged, or what a massive effect appropriate installation can have on the buildings moisture profile. New buildings are still being fitted with active heating and cooling systems which could be designed out, given better insulation and getting us closer to NET ZERO.


The CCC have included using more timber in the construction industry – which is a useful step in the right direction, but this could be expanded to all low impact natural materials (ie straw like fibres, earth etc.). Policy interventions to incentivise or require this positive change are also needed to effect transformative change in a traditionally risk averse industry. 



Skills gap: we are not ready for NET ZERO

Academic data and practitioner observations have shown that we are ALREADY seeing problems from poor/ uninformed insulation fitting. A survey undertaken for  the CITB  revealed that 78% of  respondents  considered  there  to be a skills  gap  in their occupation/profession  for  decarbonisation

This skills gap needs addressing from school up and the trades must be informed around what really constitutes appropriate materials.


We need standards: A strong set of standards, with robust enforcement, would ensure buildings are designed for a changing climate, are made from low-carbon materials, sequester carbon within their structure, deliver high levels of energy efficiency and indoor air quality, alongside low carbon heat/cooling.



2. 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?


Incentivise breathable, low carbon and environmentally benign materials:

Insulation and buffering (humidity and temperature) are two key ways to increase efficiency in heating and cooling buildings. The most commonly installed and accessible insulation materials are not breathable and perform poorly in real buildings.

Vapour permeable natural materials, including fibres and binders, buffer temperature and moisture for the life of the building, helping median fluxes (and spikes) in both parameters which are inherent within the typical pattern of usage of homes and work places, and which otherwise have to be controlled by services engineering solutions requiring life-long energy inputs, maintenance and occasional replacement. Natural materials do not emit toxic gases or VOCs in use, or when burned. Clay/earth bound structures and finishes have been shown to buffer humidity better than any other plaster or wall type and to sequester VOCs bringing health and well-being into the fabric of the building, reducing the need for active ventilation, heating and cooling. In addition natural materials are either inherently low carbon in production, often on site or extremely local and/or carbon sequestering.


Design for life: designing for disassembly and reuse for a circular economy is key to keeping the carbon emissions low and reducing consumption of resources in the long-term. This is much simpler when using softer (earth/lime) mortars and materials that have a classic design and can be screwed in place.


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


Better for the planet and better for NET ZERO: nature based materials tend to be low carbon, low toxicity and better for biodiversity and land use. They do not give off VOCs in use, or when burned. They are easy to disassemble and reuse or compost and add to soil conditioner. Soft mortars like earth and lime also enable bricks and wood to be reused more easily that the higher carbon cement.


A new market for straw/earth:

Currently there is enough straw to build 40,000 extra, well insulated, healthy 3-bed homes annually, by using JUST 5% of the wheat straw currently left in fields.

Hemp and Myscanthus (elephant grass) are also straws that can be used for building and breathable insulation. They have high yield and low pesticide requirements.


Define what is ‘natural’ in policy: Natural based materials are generally considered to be those without too much chemical/energy in processing like: earth, timber, straw, hemp, lime. If policy can define these it will incentivise their use and give them a fairer platform in the marketplace, and avoid issues with semantics later.


4. 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?


National Planning Policy Framework states in Section 14. Meeting the challenge of climate change, flooding and coastal change:


148. The planning system should support the transition to a low carbon future in a changing climate, taking full account of flood risk and coastal change. It should help to: shape places in ways that contribute to radical reductions in greenhouse gas emissions, minimise vulnerability and improve resilience; encourage the reuse of existing resources, including the conversion of existing buildings; and support renewable and low carbon energy and associated infrastructure.


Incentivise local sourcing:

Locally sourced materials should be a first choice for building infrastructure and where contractors use higher emission materials, whether by manufacture or transportation, they should be liable to prove the radical reductions achieved will offset the emissions from manufacture or transport within a short period, 5 years or less.


Give nature based materials a value:

Local Planning Authorities could apply constructional Materials Conditions (not just aesthetic Conditions), the choice of materials for construction could be a ‘material Planning consideration’ as in Wales’ One Planet Development and could contribute to the positive balance where a proposal may fall outside the LPA’s subjective constraints of its Local Plan Policies.


Regulate and quantify embodied carbon- not just carbon in use


We need standards: A significantly strengthened set of building regulations, with robust enforcement, would ensure buildings are designed for a changing climate, are made from low-carbon materials, sequester carbon within their structure, deliver high levels of energy efficiency and indoor air quality, alongside low carbon heat/cooling.



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



Change the industry, change the standards:

While existing British and Euro norms and standards including  BS EN 15804:2012, EN 15804, EN 15804, BS EN 15978:2011, EN 15804 are well established, as well as mechanisms such as BREEAM to quantify products and processes. It is clear that the emissions from materials such as cement and steel are consistently higher in production than nature based materials.

Change existing standards to reflect nature based materials and not to support the status quo.


6. 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?


Yes, Life cycle assessment of materials should include transport, but from cradle to gate (not just from factory in the case of manufactured materials).

However, materials with high embodied energy can bring higher emissions plus their travel.


To consider the overall carbon footprint and environmental impact of building fabric in a holistic, whole-life sense, local and national availability (supply and demand) as well as carbon emissions from transportation and the environmental protection policies in place where materials are sourced must all be taken into account. The UK must acknowledge carbon emissions and other environmental impacts across materials supply chains, beyond national geographic boundaries. A mandatory labelling system presenting materials’ environmental product declarations would help customers and the industry understand the real impacts of the materials specified and sourced.


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


Get green into policy from the ground up- not just green wash

Green infrastructure can multisolve by creating healthy air, biodiversity, wellbeing, reduced flooding, ameliorating urban heat island, creating homes for nature. Thinking Green infrastructure and getting rid of the grey, could be a transformative approach, but would need to be done on a systems wide basis, and would involve a change from the linear thinking of current systems within government and business. Not just green roofs, but porous streets, integrated with SuDS, removing rainwater from sewers, edible streets, tree planting on a mass scale.



8. 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?


Use less first:

Low flow appliances (taps, loos, showers) are the easiest to include in policy, and incentivise low water users. Similarly low energy in use, can be legislated through materials and home appliances.


LCA of materials and in use should be fully understood before adding more than simple rain butts, as water harvesting can be a false economy in terms of Embodied Energy of infrastructure needed, especially grey water. However, SUDs and porous surfaces should be incentivised if we are going to adapt to increasingly severe weather events. Stop building on high risk sites like flood plains.

This also goes for the fabric of the building. Keeping away from the high emitting materials like cement, steel and foam insulating materials and towards nature based materials will aid this goal.


Design carefully:

Public guidance and support is required for technology to be recognised for its advantages and limitations.

Sustainable energy systems (and related technologies, e.g. EV’s) should account for their full LCA in terms of embodied energy, related emissions and materials sourcing issues (e.g. societal benefits and child labour). Without such a baseline it is difficult to compare technologies or even to define if their use is actually a benefit. Additionally, the opportunities for repair, maintenance and recycling of sustainable energy systems should be accounted for and a methodology developed for holistic comparison between different systems and manufacturers of such systems.


Skill up:

There is a significant need for training, apprenticeships, and general upskilling for sustainable energy system design, installation, maintenance and recycling



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


It is less environmentally damaging to reuse rather than rebuild, in almost every case. Buildings can be repurposed and retrofitted or newly built with design for disassembly and circularity in mind. Nature based materials can be used in retrofit and new build, reducing carbon emissions in both the build and use phases. Nature based products are naturally vapour permeable and can buffer humidity and temperature, both essential in a changing climate and to work in sympathy with the fabric and ventilation of historical buildings. They are non-toxic to inhabitants and promote wellbeing.


Rise to the refurb challenge:

The UK has an ageing, leaky and inefficient domestic building stock that is being rebuilt at a slow rate. Approximately 2/3rds of existing UK buildings are predicted to still be in use in 2050. The proportion of housing is higher, about 3/4s.

Energy Saving Trust (EST) predicted that over half a million (600,000) existing homes need to be renovated ‘to a very high standard’ every year until 2050 in order to meet the UK’s previous 80% carbon emissions reduction target. The rate will need to be even higher now to reduce carbon emissions more rapidly. But the actual number of homes currently renovated to the required standard is minimal (100s annually).

Renovate Europe have argued that energy demand reduction of 60% - 90% is achievable for the majority of European buildings through ‘deep renovation’ incorporating ‘all available energy saving technologies’ (Fawcett, 2014). Retrofitting existing buildings can include: cavity wall or solid wall insulation; floor and loft insulation; improved glazing (all of which reduce the ‘fabric heat loss’ of a building); and draughtproofing (which reduces the ‘ventilation heat loss’ of a building) – see ‘Zero Carbon Britain: Rising to the Climate Emergency’ Report (2019) figure 3.7.

Many inspiring organisations and research programmes have shown what is possible. The UK government's Technology Strategy Board (TSB) sponsored Retrofit For the Future (RFF) projects from 2009 to 2013 demonstrated innovative approaches to deep retrofitting of social housing, using a whole-house approach for achieving an 80% CO2 reduction target (Gupta et al., 2015). The Passvhaus approach – which is gaining public recognition and popularity within the building industry, can also be applied for retrofit through the EnerPHit standard, showing how very low-energy design principles can be applied successfully to retrofitting existing buildings see (https://passivhaustrust.org.uk/competitions_and_campaigns/passivhaus-retrofit/). Other initiatives developed in Europe and trialled in the UK include Energispriong offering a radically different approach to financing and delivery using modern methods of construction: https://energiesprong.org/ , https://energiesprong.org/country/united-kingdom/

Major policy interventions considered/implemented in the UK, France, Germany and other European countries include: VAT reduction, Tax credits, Subsidised loans, Grants & Energy Company Obligations (ECO).

Include refurb/retrofit in building regs: would be a major incentive to achieving the scale of low-energy retrofit required include

Stop incentivising new build: tax structures currently incentivise new-build, incentivising reuse and refurb could change this.

Include SMEs in retrofit delivery: These are the backbone of the UKs repair and refurbishment sector, and build local skills networks. The new PAS2035 standard is a welcome step to formalise new professionalism needed in this area. But we must include the SMEs.



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


Legislate and skill up for longevity:
Incentivising meaningful training would bring skills and jobs to the sector.


Educate students and designers to specify materials that can be reused or reassembled. Many low carbon materials and processes exist but until they are specified they are not used. Educate the practitioners and public on the benefits of nature based materials, the dangers of materials which harbour moisture, encourage mould and produce toxic gases.

May 2021