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Five things architects can do tomorrow to limit climate change

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The AJ asked leaders in the sustainability field what immediate steps architects could take towards achieving a zero-carbon built environment in the near future

1) The default position should always be to retrofit existing buildings

Jonathan Tuckey, director, Jonathan Tuckey Design

Jonathan tuckey

The best way to reduce the carbon footprint of buildings is not to build them at all. 

As an industry we must minimise demolition wherever possible and maximise reuse of existing structures. Radically transforming a building creates inspiring and joyful spaces which are full of both history and future promise. 

As a profession, we must take it for granted that such retrofit schemes should be well insulated, well lit, airtight and sustainably heated. 

We must minimise demolition wherever possible and maximise reuse of existing structures

This approach could be encouraged with across-the-board incentives. Remodelling an existing building is currently accompanied by 20 per cent VAT while it’s zero for new-build projects. 

This should be reversed and the government could further subsidise the upgrading of a building’s thermal performance. It could introduce a carbon tax on materials or a carbon credit on recycled buildings, which might encourage people to recycle as much as possible. When you take a building apart in Switzerland you must separate out materials so they can be recycled. This is a very time-consuming process but the decision to demolish is taken with this in mind.

With some relatively straightforward changes to legislation we can prioritise and celebrate the reuse of existing buildings and make the process more profitable. Local communities would prefer to see their much-loved streets preserved; while making buildings more energy-efficient is better for the environment while reducing costs as fuel prices soar.

2) Reduce the use of concrete by three quarters immediately

Piers Taylor, founder, Invisible Studio

Piers taylor

Concrete is the least understood commonly used building material. We know, of course, that concrete is the most widely used material on the planet. What is less known is that it is a relatively low impact material in CO2 terms. 

If concrete is replaced by almost any other material, it would have a bigger carbon footprint. For example, using steel as a substitute for concrete is less efficient in CO2 terms, while most brick manufacturing processes produce more CO2 than cement production, including low-tech production methods still predominant in the developing world. 

Although there are wider environmental implications, the main reason concrete has a big carbon footprint is because of the huge quantities used. But also, optimising concrete designed for construction is an inexact science. It’s almost impossible to determine the optimal concrete for many applications, meaning too much cement is used, and limestone-based cement requires huge amounts of energy to produce.  

While ultra-strong concrete is being developed, allowing a more efficient use of material, ultimately we solve little through direct material substitution in any case. 

If the construction industry is to make the necessary radical reduction in CO2 emissions, we need to change the way we design. This means designing leaner buildings that are planned in dense medium-rise communities where we can use timber for the bulk of superstructure. While it is difficult to use materials other than concrete for foundations, at the heart of our problem is the construction industry’s lazy use of concrete – using too much concrete with too little thought on structures that are badly designed, such as buildings that lack the resilience to adapt or are designed with little thought of how they might be adapted in the future and are pulled down after less than 40 years. 

At a stroke, we could reduce the amount of concrete we use by up to 75 per cent if we were more strategic and only used it for essential aspects of construction that would last for more than 200 years, and instead used far more timber.

3) Understand how buildings are performing in use  

Clara Bagenal George, senior engineer, Elementa Consulting

Clara bagenal george picture

Understanding the performance of buildings that we have already constructed is the first step in better defining the challenge and understanding the steps that need to be taken to achieve a development that meets our climate change targets.  

Whole-life carbon is made up of embodied carbon and operational carbon. The latter, the carbon emissions associated with a building’s day-to-day energy use, can be measured and understood through information from energy bills or meter readings. This data can be expressed as kWh/m2 and then compared against similar developments and published benchmarks. 

These simple metrics will enable architects to better understand which buildings perform well in use and why, which will encourage them to engage with design solutions that can reduce energy and thus resultant carbon emissions.  

Understanding the embodied carbon of built projects is equally important. BIM-based tools are available that make embodied carbon assessment easier and quicker, such as HBERT from Hawkins\Brown.

These help equip architects with the information needed to take ownership of a development’s whole-life carbon impact.

4) Treat embodied carbon with the same importance as gravity or sunlight

Simon Sturgis, founder, Targeting Zero Carbon

Simon sturgis

The embodied carbon costs of the materials and systems we choose for our buildings, perhaps surprisingly, make up the majority of a building’s lifetime carbon emissions. Architects are therefore in the position to be the true custodians of their designs’ carbon performance. 

Low carbon and resource-efficiency go hand in hand, encouraging the use of recycled content, the reuse of structures and buildings, and the selection of renewable materials. 

This requires a detailed understanding of the supply chain: what things are made of, where they come from and where they will be going at the end of a building’s life. 

Architects require a detailed understanding of the supply chain: what things are made of, where they come from and where they will be going

Attributes such as long-term durability, adaptability, flexibility and designing for deconstruction and reuse (circularity) all have measurable carbon benefits. 

When we design a building’s envelope, a full understanding of the relationship between in-use operational performance and the embodied emissions of the material choices not only enables the most carbon-efficient solutions but also helps us assess the future implications of climate change on our designs. 

As this century progresses, these issues will become central to the way we design buildings and so have a significant impact on architecture.

5) Make sure every design has optimised massing and orientation

Anna Woodeson, director, LTS Architects

Anna woodeson lts architects

The days when buildings were built to resemble that napkin scribble an architect penned in his (always his) favourite restaurant should be over. 

We need to work hard enough in the early weeks of the design process to ensure our buildings are also working hard enough. This is a necessarily iterative process. Is the building using more energy just because of its form? Does it have too much surface area or too much glazing? Is its thermal envelope easy to map and therefore to detail? Is its orientation optimised to ensure it is taking advantage of solar gain in winter but eliminating it in summer? All incredibly basic principles but in getting the massing and orientation right early, we pave the way for the possibility of net-zero buildings. 

Software is developing to help us carry out more responsive analysis of the energy demand of our early models, but we find it is hard to beat the involvement of a proactive building physics engineer. 

So this is not just about the rigour with which we approach our early design work but also about who we work with and how we procure buildings. 

The architectural competition process, for example, often forces a building design in weeks, without the support of a wider design team. This does little to support the collaborative process required to develop a very low-energy building. Perhaps instead we should be judged on our proposed approach to a commission.


Readers' comments (6)

  • Plenty of thought provoking information and ideas here, and Piers Taylor surely makes a very pertinent observation about '...buildings that lack the resilience to adapt or are designed with little thought of how they might be adapted in future and are pulled down after less than 40 years'.
    Add Jonathan Tuckey's comment on the requirement for deconstructing and recycling redundant buildings in Switzerland, and I think of what are - literally - modern buildings in central London that are apparently useless and get torn down with little or no regard for recycling anything other than steel and rubble
    And sometime they're of high architectural quality - Broadgate, anyone?

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  • And don’t beat ourselves up?! Talk to clients about how they could save money, and use the incentives that have been made available by Green Bonds. £1Trillion/annum for 10 years! But paid out by LAs, so don’t hold your breath?!

    PTE are doing good work in Cambridge, showing how Passivhouse can work? They could do it in Brentford too, as they have the opportunity now to reuse the Police Station Tower, passively. Talk to me Tom? But it must be attractive to the end user/buyer.

    As we said in the 70s, Long Life, Loose Fit, Low Technology. But perhaps Higher Tech this time?

    There is a vast market out there for retrofit, but it might be a bit boring for spaffing architects? Might be better done by such as Anglian or Everest?

    Time for everyone, girls and boys, to get over Brexit and sort this out. We, Britain, should be the world leaders, as we have been so many times before!

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  • Good to see this piece and I don’t disagree with any of the ideas.
    But shoukdn’t FABRIC FIRST be up there somewhere? Building Regs is the minimum standard legally permissible, but as a profession we should nearly always be advocating better standards, such as Passivhaus for at least the fabric insulation and airtight levels.

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  • Some sensible ideas here and I must say that I agree with John—Fabric First. See his zero carbon retrofit house in 'The Zero Carbon House' (2011) M.G.Cook. But if only it was up to architects...the 2015 legislation was kicked down the road until 2025. Further lost decades on this issue are not feasible.

    Post occupancy evaluation is imperative (See the Design Quality Method (DQM)) and BIM has the capacity for accurate metrics, unlike tick box eco-points schemes. As Prof Al Bartlett said, calling yourself sustainable does not make it so, and he also noted that extinction is forever.

    'Sustainable energy without the hot air' (2009) by the late, great David Mackay is by far the best source for a scientifically quantified analysis of the energy usage problems and potential solutions. He purposefully set out to analyse and accurately quantify energy use across the board, because he was sick of adjectives such as ‘huge’ and ‘massive’ being applied the potential of renewable energy, for example. A free digital version of the book is available from www.withoutthehotair.com as well as a ten-page digital synopsis. Mackay, unsurprisingly, recommends ‘lifestyle change’ among this ‘first three strategies to reduce energy demand’. A paperback version of the book is available from Amazon etc for about £20. David Mackay’s analysis is simply the best out there, and he was appointed Chief Scientific Advisor to DECC for several years before his tragically early death. I had the pleasure of attending one of his lectures and meeting him when he visited BRE.

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  • Thanks to Martin Cook for the recommendation of David Mackay's 'Without Hot Air' link. I just finished reading the ten page synopsis and would definitely recommend it as an introduction to what our sustainable-energy future might look like. Watch out for the www.withouthotair.com link, best type into google rather than your browser. On my browser at least, it gets hijacked by something fishy looking.. (ww5.withoutthehotair.com)

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  • While I am supportive of measures architects could take to achieve a zero-carbon built environment, I was confused by the mixed messages in Piers Taylor’s comments calling for reducing the use of concrete by three quarters. He correctly notes concrete has a lower CO2 footprint than most other building materials, but ignores the fact that wood used in construction (particularly for mass timber designed structures) also has a high carbon footprint. While innovative changes are indeed being made in the industry that lower the CO2 content of cement used in concrete, limiting concrete to “essential aspects” of construction (i.e. anything lasting 200 years) and using far more timber is illogical and unrealistic. All tall timber buildings in reality are hybrid structures that require concrete or steel for structural support and safety. And it is unrealistic to think that high-density cities of the future can be built with more timber harvested from already over-stressed forests in lieu of concrete.

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