Marion Baeli is Principal, Sustainability Transformation at 10 Design, member of 10N, a collective created by Egis.
Her focus as an architect is on decarbonisation, achieving this on existing buildings through retrofit and adaptation, to improve their energy efficiency and to add capacity with efficient use of materials.
MB : We need to find alternative systems to keep people warm and simply moving to electricity is not going to work in the sense that air sourcing for example are not always able to provide sufficient amount of heat inside the homes, if the home is leaking energy through all gaps in the fabric, sort of speak.
MB : So that's why we're looking at improving the performance of windows, performance of walls, and also introducing systems such as ventilation with heat recovery, to be able to keep all the heat that we are putting into the building, to keep it inside the building. And obviously, once the energy demand is low, it means that everybody around the UK can have enough electricity to power their homes.
Welcome to Engineering Matters. I’m Tim Sheahan, and I’m Alex Conacher. In this episode, part of a mini-series produced in partnership with Egis, we will examine a project in east London that illustrates how even relatively new buildings are not immune to energy inefficiencies.
Marion’s recent focus has been on a property at the former 2012 London Olympic Village, now called the East Village, in Stratford, East London. The structure is only 12 years old But still largely powered and eating via fossil fuel.
Marion sets about reducing carbon emissions from the site.
MB : So we carried out a building performance evaluation on site with Build Test Solution and evaluating the actual u-value performance of the walls, the windows…
A U-value expresses the rate at which heat is transferred through matter—in this case, through a building.
MB : We did extensive thermal imaging, photographing also, and air pressure test. So we had really good information on the actual performance of the walls, the windows, where air leakage was and any thermal bridges. So that gave us a really good start to say, okay, it's not actually performing exactly as it should.
MB : So it’s addressing all these discrepancies and making sure that we can improve on the existing fabric so that any heat that we bring into the building is actually able to stay in the building in a very efficient way. So improving the air tightness, improving the insulation, improving the window frame installation and perhaps mitigating thermal bridges as much as possible is what we are looking to do.
Retrofits have an upfront capital cost and a careful balance has to be struck between cost of the measures and the performance that the building is able to achieve.
MB : It's also about choosing materials that have low embodied carbon to be able to mitigate the impact that you have while constructing anew. So you need to be cognizant of this and make sure that you're modelling your carbon emission as you're designing and retrofitting. So there is now a fairly good range of materials that you can use that are mitigating that impact.
MB : And let's not forget that we also have an enormous shortage in housing numbers, especially in London. So adding on an existing site means that you don't add pressure to the land in other areas of the city.
MB :You can't have it all. But I think this is a really good mix of balancing, all these variables and these demands for lowering carbon, new units, and retrofits.
The property’s owner is considering financing the retrofit by constructing another three stories to generate more revenue.
MB : So this would be a game changer in terms of the entire accommodation and volume for the whole of East Village.
MB : So there is always ways, you know, like people add an extension to their home, an extension of their garden to add value, and they can also, while they are doing retrofit, they can add value to it as well. So this is a key opportunity when you are thinking of doing any amendments to your property, to either start from the need for adding an extra space to justify your retrofit of the older part of your property, or use it to finance, like in East Village, where we would actually create this extra space to help finance the retrofit to the rest of the existing building.
Another balance has to be made between maintaining the aesthetic and functional benefits of the building’s features while improving its energy performance.
MB : We know that through the modelling that we've done on the building that these properties will overheat because there is no external shading at the moment.
MB : So we're probably going to head towards shading, full shading of the glass because there is also the value of being able to see floor to ceiling in these properties. The windows are relatively narrow, but they're floor to ceiling and it's important to give this visibility to the outside for the occupants.
MB : You only get one chance to have a go at retrofitting so we need to get it right so we need to make sure that we spend the required amount of time to investigate all the options and have all the key stakeholders involved to be able to make sure that we choose the right materials, techniques and sequencing and meet all the client requirements for both decarbonisation, maintenance and also asset value.
Extending the lifespans of buildings would be easier if they were designed at the outset with the potential for later change in mind.
MB : This is definitely an area that some pioneers are testing already.
MB : There is, for example, a building called Reverso in Bordeaux, which is designed to cater for both residential and commercial offices.
A building like Reverso is designed for the long term. It is flexible and resilient to future changes of use, but that is not the case for every building. Many are not designed with the flexibility needed for adaptation between uses.
MB : So it's difficult to convert in housing.
MB : So we need to be able to construct more flexibly to be able to give future occupants the choice of what they might like to make with that building. And we see the cost of this inflexibility at the moment with offices in the city
The built environment accounts for 40% of carbon emissions and decarbonising the housing stock in a country like the UK, where almost 9 in 10 homes – 17 million – are heated with gas will be a long hard slog.
Even so, early wins can be had by converting the oldest properties first.
MB : It’s probably the most efficient way to do it, because the other homes are tiny bit more efficient already in terms of thermal performance. So if you start with a property that’s really badly performing, the difference that you can make on that one house is actually much bigger, so in terms of carbon saving, you might save lot more carbon retrofitting a Victorian house to make it super energy efficient opposed to a fairly good 1970s cavity wall property that already has some insulation.
In 2013, Marion published a book about a selection of buildings she had retrofitted in the UK. This year she has updated it, adding 4 more case studies and assessments of how adaptations to some of those initial projects have performed.
Its findings illustrate the long-term benefits of retrofitting
MB : What we've learned through it is most of the energy efficiency measures actually are still working today.
Marion says work needs to be done urgently to retrofit buildings for energy efficiency if we hope to reach net-zero goals.
While she has not seen as much progress as she would like, she has cause for optimism.
MB : And so we are seeing a little bit more energy and a bit more finance into it, but it's still not delivering the numbers that we need to deliver at the speed that we need to deliver it then by, especially in the UK, if we want to achieve net zero by 2050 or earlier.
MB : So I cannot stress enough the absolute urgency that we need to address the rolling out speed of the retrofitting of the UK building stock.
MB : The urgency of retrofitting the housing stock is relevant for the UK but for the rest of the world as well.
