Earth Building UK and Ireland SBE0117
Written Evidence from Earth Building UK and Ireland (EBUKI)
Earth Building UK and Ireland are a registered charity which works across the field of sustainable construction, research and education. Additionally we are the UK partner to the UNESCO Chair on Earthen Architecture and have Trustees and Members in Construction, Production, Consulting, Higher and Further Education.
EBUKI Mission Statement:
“achieving the UN 17 Goals for Sustainability through the development of building with earth, using education, policy, research and conservation in the United Kingdom, Ireland and beyond .”
EBUKI Aims:
1. To what extent have the Climate Change Committee’s recommendations on decarbonising the structural fabric of new homes been met?
According to recent EPC data sales and rentals of earth buildings sit at around 1,000 per year, the majority of which are more than a hundred years old proving that some of the lowest carbon buildings are also long-lasting1. However while the CCC’s recommendations do include measures to insulate and retrofit in a very general way the complexities of temperature and humidity mitigation are largely absent. What is clear is that buildings are still being fitted with active heating and cooling systems demonstrating that the fabric where it has been built new or retrofitted has not been done to a sufficient standard to obviate the need for such systems. In short we have a long way to go to meet the targets set which includes the need for:
New build standards: Implement a strong set of standards –with robust enforcement –that ensure buildings are designed for a changing climate and deliver high levels of energy efficiency, alongside low carbon heat2.
We are not aware of any work on such standards in our sector other than that which we have developed ourselves. Until a comprehensive standards program is undertaken then clearly robust enforcement remains a long way off.
Additionally the issue around skills is addressed thus:
An upcoming report by the CITB identifies low demand for skills and training linked to Net Zero, and finds the current training supply not yet ‘Net Zero ready’. A survey undertaken for the CITB revealed that 78% of respondents considered there to be a skills gap in their occupation/profession for decarbonisation3.
Underlining the point that even where standards are in place the skills to deliver them would not be. In fact the Sixth Carbon Budget is silent on building fabric, reference is largely made to heating energy sources rather than materials production, insulation is mentioned only generically not by type and therefore the embodied energy difference 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.
1 https://epc.opendatacommunities.org/domestic/search
2 The Sixth Carbon BudgetBuildings, https://www.theccc.org.uk/wp-content/uploads/2020/12/Sector-summary-Buildings.pdf page 55
3The Sixth Carbon BudgetBuildings, https://www.theccc.org.uk/wp-content/uploads/2020/12/Sector-summary-Buildings.pdf page 74
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?
Insulation and buffering are two key tools to increase efficiency in heating and cooling buildings, this includes buffering of humidity and temperature, two linked issues. Materials commonly manufactured for structures and insulation perform poorly once ‘real world’ issues like humidity are introduced, structures are not vapour permeable and insulation performance falls rapidly where it is. In both instances reliance on active heating and cooling as well as ventilation become inevitable increasing not only the high embodied energy of the materials but also the long term energy running costs of buildings.
Contrast this with vapour permeable natural materials, fibres and binders which by their nature are vapour permeable as well as temperature buffering. Added to this they are safe, do not emit toxic gases when they burn or emit other volatile organic compounds, VOCs, in use. Indeed clay 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 very 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.
3. What role can nature-based materials play in achieving the Government’s net zero ambition?
Essentially reduce both the embodied and in in-use energy of all new and retrofit projects in a way unparalleled with conventional manufactured systems. Additionally there are great opportunities for training, job creation and circular economy issues. Earth in particular is widely available, is often seen as a waste at building sites and is removed and dumped at great cost. Site conversion of soil into a range of building materials is not a fanciful concept but does require planning.
Clay as a binder lends itself to high mass load bearing structures and low mas thermal insulators and buffers. Materials such as chalk, often seen as unsuitable for use has been shown to be a useful admixture to a range of clay products as well as producing two storey load bearing structures on their own.
Very low energy to extract and process, very low energy in transportation both make earth local and affordable and in terms of mass materials as low can be found anywhere.1
1Earth concrete. Stabilization revisited, Henri Van Damme a,b,⁎, Hugo Houben c Cement and Concrete Research 114 (2018) 90–102
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?
We are in agreement with the National Planning Policy Framework where it 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 infrastructure1.
We take this to mean that materials such as site and locally sourced subsoil should be a first choice for building infrastructure and where contractors wish to use higher emission materials, whether by manufacture or transportation, they should prove the radical reductions achieved will offset the emissions from manufacture or transport within a fixed period, say 5 years or less.
There is currently no quantifiable value within the Planning system for the use of natural or renewable materials for new dwellings. If Local Planning Authorities would apply constructional Materials Conditions (not just aesthetic Conditions), the choice of materials for construction could be a ‘material Planning consideration’ and could contribute to the positive balance where a proposal may fall outside the LPA’s subjective constraints of its Local Plan Policies.
1National Planning Policy Framework Ref: ISBN 978-1-5286-1033-9
5. What methods account for embodied carbon in buildings and how can this be consistently
applied across the sector?
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. However it is clear that the emissions from materials such as cement and steel are consistently higher in production than a swathe of natural materials and agricultural ‘waste’, sequester no carbon and furthermore cannot fit the description of ‘circular economy’, a target which few commercial standards attempt to measure. In other words although there are a slew of existing standards they are written by and large to measure an existing industry and largely fail to compare the overall properties found in natural fibres and binders.
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?
This is a strangely worded question suggesting the carbon impact of materials lies largely in their transportation and that alternative building materials will always come further than ‘conventional’. Materials with high embodied energy bring higher emissions however far they travel. It should also be stressed that construction with soil and agro-waste is often the shortest distance between source and site. Without the cost of carbon being measured and financially costed any change to the use of such materials will have to be controlled through legislation if emissions are to be curbed.
7. How well is green infrastructure being incorporated into building design and developments to achieve climate resilience and other benefits?
The resistance in changing standards, in education, in training, in the development of learning outcomes and curriculum and in the continued shielding of high emitters from paying the true cost of cleaning their pollution the incentives to change are low. Tax the polluters, train the designers and builders of tomorrow and invest in clean manufacturing if you want to increase green infrastructure.
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?
All of these issues are important as is the need for behaviour change. Simple decisions like the siting and aspect of buildings, avoidance of high risk sites to flooding etc. have long term benefits. None of these are total solutions in themselves and in fact there is no one solution to all the problems we face in reducing emissions and capturing carbon. But in terms of building fabric we know that cement and steel not only emit vast amounts of carbon in manufacture they also capture and store no carbon either so that whatever minimisation of carbon emissions we need to achieve these materials have to be used in only the most sparing amounts.
9. How should re-use and refurbishment of buildings be balanced with new developments?
All we can comment here is that clay finishes and structures lend themselves to both retrofit and new build, reducing carbon emissions in both the build and use phases. Clay bound products can produce a wide range of insulating and temperature buffering products, from load bearing elements to code meeting insulation, all of which naturally buffer humidity and sequester VOCs. These can be used in a wide variety of ways in retrofit, either for complete remodelling or simply to cure long running issues of damp and cold. Clay bound materials adhere to almost any surface so retrofitting to structures from the 1980’s or the 1880’s are potentially not so different.
That said clay can bind crushed demolition material, be dug up on brownfield sites and site manufactured for use as well as in remoter rural settings where transport would otherwise be necessary to bring heavy masonry components. There is a factory currently working on the edge of Paris turning tunnelling spoil into products, clay is very versatile.
10. What can the Government do to incentivise more repair, maintenance and retrofit of existing buildings?
Tax polluting industries like cement and steel and require a higher standard of proof for the need to demolish existing buildings in both public and private ownership.
Clay bound materials need skills and knowledge to turn the raw materials into mix and then apply it. Incentivising training, bringing skills and jobs in the sector would certainly be a big help. Finding people with the skills is often a block to their use. Educate students and designers to specify these materials. Many of the materials and processes exist but until they are specified don’t get used. Educate the public on the dangers of insulating materials which harbour moisture and produce moulds, and on insulation materials which burn and produce toxic gases. Build and retrofit government buildings including housing stock with low carbon natural materials, setting a target for both carbon sequestration and emissions reductions.
May 2021