Earth Building Association of Australia, EBAA              SBE0096

Written evidence from the Earth Building Association of Australia, EBAA

 

This submission is written on behalf of the Earth Building Association of Australia.  We admire this request to directly contribute to the democratic process and we believe we have something useful to share in what is currently a global quest for solutions to addressing GHG emissions.  We have been making similar submissions since 2003.  We can build zero carbon buildings now and we can retrofit older earth homes to be zero carbon full LCD simply and economically.

 

     Executive Summary

 

     The global reliance on finite energy resources across all industries, including the building industry, needs to change dramatically to address GHG emissions and climate change.  The world has come together and committed to this.  For the past twenty to thirty years some of us have been working towards this goal.  Some would question whether we have succeeded.  I believe we have had some success. There are hundreds of thousands of earth buildings in the UK and Europe dating back 400 years that can readily achieve full LCD carbon zero and new earth buildings can be built better today combined with knowledge from new technologies.

 

              For a solution to be valid it must be holistic, considering all costs to the environment and human lives.  Short term, narrow thinking has produced failures and problems. There are issues with both design and materials used in modern buildings.  Modern, well insulated, airtight structures are prone to overheating and reliance on RCAC. This is a problem in cool temperate climates, though in hotter climates it is potentially disastrous and absolutely not climate change resilient.  It makes the transition to renewable energy much more difficult and energy more costly. The legacy of flammable cladding is evident around the world. 

 

A global solution should be universally available to all people, in all economies and in all climates.  Developed countries need to reduce energy and resource flows by 80%, though as the populous developing nations emulate lifestyles of developed countries, we will see the effects of unsustainable environmental practices amplify.

 

     In some places, we are returning to slow food, organic farming, farmers markets and recycling through choice.  Earth and natural fibres offer us the materials for natural building.  Vernacular designs and traditional building give the architectural clues we need to transform the building industry to be more sustainable.  We once lived completely sustainable lives and we can do so again, though more agreeably, through choosing appropriate technology.

 

     Our buildings don’t need to be worse, they can be better. It is possible to build safe, healthy, comfortable, desirable, affordable and sustainable homes with unfired earth and natural fibres.  It is possible for the wealthiest and the poorest.  It is possible to build passive low energy earth buildings in any climate, that are climate change resilient.

 

     All of the issues of modern building can be reviewed and solutions developed by considering full Life Cycle Design including all operational energies and embodied energy and when the metric used to report is a carbon metric such as the Common Carbon Metric.

 

     Renewable economies of the future can’t be modelled on fossil fuel economies.  Buildings can’t be totally dependent on finite resources and  energy at the rate they are consumed at present.

 

     We need to be observing and working with nature, as we are not separate from it.  Cities need to be more like ecosystems.  Buildings need to be green built environment and green infrastructure.  We need to embrace and utilise all available sustainable building technologies and renewable technologies such as rainwater harvesting, waste water reuse, roof gardens and solar collection to reduce the environmental impact of the buildings and build healthier and more sustainable buildings.

 

 

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

 

1.1.    It is difficult for Earth Building Association of Australia to comment in a detailed manner on this question with less direct experience of the UK approach and CCC recommendations.  However it is suggested that if the goal is a targeted allowance full operational energy/m2/annum without consideration of embodied energy and carbon intensity of the energy required or available, then the recommendations may have not been met, or missed the mark and certainly may have fallen well short of what is possible. If the approach is one that simply concentrates on envelope efficiency and U values for example, for reduced operational space heating/cooling/mechanical ventilation, without consideration of the passive low energy alternative then you may fail progressively in the near and distant future.  Passive low energy design achieves much more including indoor air quality, adaptive comfort, natural ventilation and natural conditioning. It offers climate change resilience and avoids the adverse impact of RCAC on the generation and supply of electricity.

 

1.2.    We need to be using a holistic approach to reducing GHG emissions and that involves consideration of full LCD.  We are moving towards zero carbon buildings and zero carbon economies so we also need to be thinking in terms of the common carbon metric rather than an energy metric.  When we limit thinking in terms of energy we tend to simply think in terms of envelope efficiency.  We are missing the possibility of natural gains that can be employed in appropriate climate responsive design, utilisation of zero carbon intensive or low carbon intensive solutions to achieve adaptive comfort.  

 

1.3.    For example, a building design is modelled and it accrues a predicted cooling energy demand in summer measured in kWhr/m2/yr.  Forget energy for a moment and think about comfort instead.  Can summer comfort be satisfied through natural ventilation logic?  If the building has sufficient effective thermal mass can the building be managed with mass linked ventilation at night and through closing down to minimum healthy air changes by day?  It may be that the building avoids RCAC altogether or peak load demand is shifted.  A building is modelled and it accrues a predicted heating demand in winter.  The fabric could be improved to reduce winter heating load.  Could the building design be improved so that a design adds on features such as a conservatory, skylights or tromme wall facades to resolve the problem, by harnessing natural energy. Could the addition of a passive plant such as a roof mounted solar space heater or solar evacuated tube powered hydronic heating system resolve the problem?  This is also potentially easier in existing buildings. 

 

1.4.    The end game is reducing carbon, heating costs, and improving comfort.  

 

1.5.    Perhaps the modern approach has been too focused on improving envelopes and reducing energy demand at the expense of indoor air quality and reliance on RCAC to resolve overheating.  When we think of carbon and comfort and health simultaneously maybe we begin to remember appropriate design and operation of natural ventilation.  

 

1.6.    To achieve a low carbon or carbon zero economy we will need to minimise our need for energy and our peak load demand especially at night.  We will need energy storage.  There are two ways to make buildings comfortable.  Minimising conditioning energy losses through envelope efficiency - the modern approach. This is like a motor boat. It relies on cheap and bountiful fossil energy.  The more sustainable approach that works more easily with renewable energy is to maximise natural gains in naturally conditioned buildings through the use of appropriate climate responsive design.  This is like a sailing boat.  

 

1.7.    We should be able to create best practice passive low energy buildings given simulation tools, the lessons of the past and new technology.  Just look at the 2021 America’s Cup for inspiration in what performance is possible without using energy

 

1.8.    Designing better buildings isn’t as simple as U values, airtightness, avoiding thermal bridges and using mechanical ventilation with heat recovery to maintain minimum ventilation. 

 

1.9.    We need to maximise capture of natural gains (cool of night, warmth of day) when they are available and store enough to utilise until those conditions return.  Natural gains are available as long as night follows day.

 

  1. 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?

 

2.1.    The best materials are those which have low or negative embodied energy in terms of full cradle to grave/cradle impact including inputs for extraction, processing, transport, construction, maintenance, demolition and hopefully reuse rather than landfill.  

 

2.2.    Materials that can be optimised for climate and that can respond to climate for use in passive low energy buildings are the most valuable.  Thermal mass is useful in fabric energy storage.  It is vital in achieving summer cooling, safety in heatwaves and climate change resilience due to ability to balance diurnal and even day to day fluctuations, even rapid ones.

 

2.3.    Generally, the hotter the climate the more thermal mass can be utilised for full fabric internally and externally.  Wall thickness improves performance. Insulation is useful in colder climates and in mass walls with no sun on them where there is no dynamic enhanced insulation value.

 

2.4.    Generally, colder climates will benefit from insulation against losses.  Unfired earth is unique in that natural fibres and light weight aggregates can be added to optimise thermal performance for climate. This was understood by past generations. Cob buildings with density of 1500kg/m3 were popular in England and Pisé with a density of 2100kg/m3 or Adobe with a density of 1750kg/m3 was used in hotter climates such as Africa and the Middle East.

 

2.5.    Thermal modelling can determine best density and wall thickness for orientation or zone within the building for use in passive low energy architecture. Best performance is achieved with appropriate climate responsive design.  In economies where resources and energy flows have been unrestricted modern “energy efficiency” is about creating PMV comfort conditions and the focus is on reducing conditioning losses through envelope efficiency including airtightness.

 

2.6.    A renewable economy will require minimising the need for resources and energy.  It will be about harnessing natural gains like night time cool, daytime warmth, solar gain and storage.  Fabric energy storage is directly useful with a lower embodied energy than battery storage.  It lasts the life of a building.

 

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

 

3.1.    Nature based materials like unfired earth and natural fibres like straw and hemp can surpass the government’s net zero ambition now.  Full LCD carbon zero and beyond carbon zero earth buildings exist and the good news is that existing buildings can be simply retrofitted to be better.  A 28-yr-old mudbrick home in Australia is 113% full LCD carbon zero as assessed by eTool Global. It is being improved with roof mounted solar space heating and cooling. In new builds we are able to improve design and performance through optimising density and thickness of earth walls for climate.  EC funded research at CobBauge project supports this potential.

 

3.2.    Passive low energy earth buildings are safer, healthier, more comfortable, affordable, desirable, climate change resilient and sustainable.  Crop based natural fibres reduce CO2 whilst growing and locking carbon into buildings preserved within earth.  Earth provides thermal mass material with the lowest embodied energy figures equal to plant based fibres.

 

3.3.    Earth is widely and locally available, virtually unprocessed, non-combustible, doesn’t rot, is non-toxic and endlessly recyclable and has great hygrothermal properties. Earth walls eventually reach a very dry state through initial drying which is through evaporation rather than chemical induced hydration or firing. When dry they don’t readily absorb water rather they shed it which gives this form of masonry consistent thermal properties rather than wet or dry performance.

 

3.4.    Earth keeps indoor environments at around an ideal 50% humidity and provides the best form of comfort through surrounding radiant warmth or coolth.  It does its work automatically with good design and simple operation of natural ventilation. Natural and recycled light weight aggregates are worthy of consideration. Expanded clay and foamglass for example.

 

  1. 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?

 

4.1.    Encouraging the demolition of solid old structures through planning is counter-productive if we are trying to reduce resource and energy flows.  These buildings have already paid for themselves in terms of embodied energy when they reach the expected life of a building.  They should be awarded a zero embodied carbon status or better a negative embodied energy credit that is greater the older they are. Developers could use the LCD credits.  It is better to remodel these buildings and utilise them especially when thermal mass such as burnt clay brick is precious and often high in embodied energy and costly to build new. 

 

4.2.    Solar gain is going to be more valuable the more we focus on passive low energy architecture and renewable energy.  Planners need to consider solar orientation, avoiding overshadowing by new developments, controlling heights of buildings when looking at the potential of development sites and in subdividing and planning for greenfield developments.

 

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

 

5.1.    Full LCD tools are commercially available. There are internationally accepted standards for calculating LCD.  For large scale developments there is a budget for detailed accounting for LCD. For smaller developments the cost needs to be reasonable. eTool Global has affordable options for small scale developments and even more affordable options using their App.  The App would be popular with voluntary aspirational retrofitters. eTool Global reports using a carbon metric.

 

5.2.    The entire point of energy efficiency and agreeing to internationally binding targets is to reduce GHG emissions.  Any tool that doesn’t report using a carbon metric and consider all aspects of the resources and energies used in buildings over their lifetime is not as useful in achieving the aim.

 

  1. 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?

 

6.1.    Yes, of course, LCD should account for every input including transport to site from the origin of the source material, extraction, processing if any, inclusion into the building, accounting for life span, maintenance and demolition and reuse, recycling or cost of disposal.  eTool Global is developing flexible templates for their App. 

 

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

 

7.1.    In Australia, the uptake of roof top solar has been huge due to subsidies, affordability, favourable payback equations, high home ownership and the rising cost of electricity driven to a large extent by the peak load demands of RCAC units in poorly designed and orientated buildings. That is effectively light weight buildings with good envelope efficiency.  These modern “energy efficient” buildings are reliant on RCAC. 

 

7.2.    Research involving thermal assessment modelling, auditing and monitoring done by the CSIRO team Evaluate NatHERS 5 star homes gave interesting results. Homes with improved envelopes are easier to heat though have greater cooling demand that is directly proportional to envelope efficiency. The better insulated and sealed the envelope the greater the real cooling demand. This isn’t sensible given climate change predictions.  Cooling loads are becoming an issue even in much milder European and UK climates.

 

7.3.    If buildings were passive low energy designed having good solar        orientation the potential would be greater for reduced whole of house operational energy demand, through better solar gain for reduced space heating, easier shading control for cooling, best potential in PVs and Solar Hot Water Systems, rooftop solar space heating/cooling/ventilation units and outside clothes drying. We need buildings that are green infrastructure.

 

7.4.    Nature decentralises.  Everything is a complete system and part of an ecosystem working in unity.  We have somehow gone the opposite way creating buildings, towns and cities that a totally dependent, not positive development.

 

7.5.    Until passive low energy buildings can be assessed on ability to provide adaptive comfort and healthy air quality, new modern developments will continue to produce “envelope energy efficient” buildings that continue failing to deliver now though more so into the future. 

 

7.6.    My passive low energy home is 113% full LCD eTool Global, rates poorly in terms of predicted envelope efficiency in NatHERS predictive space/cooling energy, costs very little by comparison to the national average to operate and it rates exceptionally well in NABERS tool.

 

7.7.    My requirement for zero carbon space heating will disappear by 2050 given climate change predictions. The cooling requirement will remain zero and my home will be safe in heatwaves and bushfires without power. Natural conditioning is supplied through mass-linked ventilation.  Temperature and humidity control are provided by the earth walls. Minimum air changes are possible without losing efficiency due to the thermal fabric storage.  In modern well sealed and well insulated buildings, with no effective thermal mass, it is either healthy indoor air quality or predicted energy efficiency.

 

7.8.    In France new buildings over a certain size must have a roof covered in PVs or a green roof. This is a worthwhile planning initiative.

 

  1. 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?

 

8.1.    In a full LCD analysis all of this is considered.  Water tanks have an embedded cost, a lifespan and they reduce water treatment and pumping which has a cost that can be calculated. PVs have an embodied cost and potential and this is assessed over their lifetime in LCD tools. In NSW BASIX most of this has been considered since 2005 including choice of plants for the garden, rain water harvesting, waste water, grey water reuse etc. Maybe worth having a look at NSW BASIX. Simple online tool and affordable certificates.

 

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

 

9.1.    Older buildings are often too valuable to demolish.  Only when we start to consider embodied energy do we recognise their full value.  They are often redeveloped to make them more “energy efficient” though until we consider carbon intensity perhaps we are reducing energy use though not reducing carbon.  Maybe we are reducing operational energy though embodied energy rises by the same amount or more.

 

9.2.    New development is often driven by maximising profit by replacing low rise buildings with taller ones. I believe there may be a lower maximum height for buildings that is seen as sustainable. Tall buildings require mechanical ventilation, mechanical lifts and pumps.  It is only the ability to be wasteful with cheap fossil energy that allowed them to be built.  In time we may start to recognise that building taller than this isn’t sustainable in any sense other than economical based purely on the value of a square metre of the land.  

 

9.3.    Whether this eventuates or not high rise buildings in CBDs represent a small part of the built environment and one that may only be sustainable through carbon offsets.  

 

9.4.    Tall buildings deny other buildings their right to solar gain. Solar gain will become more and more valuable for natural lighting, solar gain and solar power in a renewable economy.  COVID has proven the vulnerability of large buildings with mechanical ventilation systems and access limited to lifts.  These buildings have been the incubators and were the first buildings abandoned and the last to be reutilised.  

 

9.5.    Work from home in regional areas is being made possible with internet communication and eventually this and the ecological and operational costs of high rise apartments and office towers may change the way we value CBDs and the shape of buildings and constant redevelopment into the future.  

 

9.6.    Earth Building techniques can be used to provide passive low energy buildings up to 4 or 5 stories that are safe, healthy, comfortable, desirable, affordable and sustainable.  Much of UK and Europe was built this height in the past before mass use of fossil fuels allowed us make less sustainable decisions and actions.

 

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

 

10.1.    Value them as discussed previously.  They are often good buildings and simply victims of development pressure. This pressure leads to dilapidation and demolition. Embodied energy credits and zoning impact the viability of older buildings and how much is spent on them and their fate. Potential for work from home, public transport and walking and cycling options also affect property values and investment in older buildings.  A lot of control is in the hands of local and state government policy.

 

10.2.    Minimum envelope efficiency values have led to problems with worth of buildings and their perceived value. Modelling of heavy walls verses light weight assemblies may or may not give a better understanding of the difference between the two.  In Australian climates light weight walls require the same R value irrespective of climate though modelling shows that thermally massive walls may perform better in hotter climates and in cold climates. Just a fraction of the insulation needed in light weight wall assemblies is required to alter the thermal dynamics of the mass wall system favourably.

 

10.3.    Perhaps older massive buildings require less external insulation to allow them to achieve adaptive comfort.  Perhaps their ability to negate the need for RCAC needs to be rewarded. Perhaps if the energy required for heating is zero carbon or low carbon that is enough to satisfy code. If a solar hydronic heating system or roof mounted solar space heater, conservatory, window upgrade, roof insulation upgrade or pellet heater is used to provide comfort is that not achieving the aim of reducing carbon? Perhaps silicon sealers can keep porous burnt clay masonry walls dry and improve wet wall performance. Ditto chemical DPC or other solutions to control rising damp.

 

10.4.    NSW BASIX online sustainability tool is worth a look.  It has three areas for targeted reductions - Thermal Comfort, Energy and Water. It would need to be set up for UK climates and conditions. Some things like swimming pools and gardens and water saving won’t be as important a target in the UK. Embodied energy isn’t there though could be added. The idea is to encourage reductions in all areas.

 

10.5.    At present BASIX aim for 60% reduction over 2005 baseline in all three areas. It is a simple and affordable tool to use. A certificate costs $50 if you use self-service. Compliance is limited to new buildings or substantial renovations/alterations. Perhaps existing homeowners not obliged to use the tool could use the tool voluntarily to obtain a certificate. They could be encouraged if the certificate led to lower rates or taxes or utility bills. Subsidies could be used to encourage change.  UK has a lot of council owned buildings. Perhaps the government could work with councils to make the reductions.

 

10.6.    NABERS is a tool for auditing existing buildings. It is useful though the first version developed by a NSW government department was much better than the revision done by consultants some time ago, in my opinion. Tools like this are useful at point of lease or sale.  Economics can be the driver if labels are mandated by government.

 

May 2021