BDP Podcast

Hello. I'm Alan Davies. I'm an architect and Heritage League and PDP. Welcome to the first ever Becky podcast series It's called Old Buildings New Beginnings. In this series, we discuss the current thinking relating to the re-use of old and existing buildings. It's a very current topic across the globe retrofits and refurbishment, rather than demolition and replacement buildings. Has been steadily gaining traction as we seek to reduce our impact on the environment and create better places using buildings and structures that already exist.

In 2018. Carlo Infante, the president of the American Institute of Architects, stated that the greenest building is the one that already exists We will discuss topics including adaptive reuse, sustainability, accessibility, improving performance as well as the cultural significance of keeping old buildings. Why build new when you can repurpose the old? Welcome to the conversation. Hello and welcome to Old Buildings New Beginnings where this week we ask the question Can we make historic buildings sustainable?

The reuse and adaptation of old buildings has been promoted by a wide range of organizations concerned with sustainability, including the World Green Buildings Council and the American Institute of Architects. Here in the UK, architects and engineers have declared the climate emergency and fired by the same issues. The Architects General launched the campaign in 2019 called First Out championing the re-use and retrofitting of buildings over demolition and rebuild.

So today we discuss how sustainable can old buildings be and what can we do to adapt existing structures to be more sustainable. Joining me to answer these questions today are three colleagues, Lucy Townsend, sustainability consultant and associates in our London studio, James Hepburn, Building Services engineer and principal in the London studio, and Ilich to Stern, the architect director and leader of the Heritage Team, again in our London studio.

Let's kick off by discussing the ways in which historic buildings are sustainable or less sustainable than new buildings again, I think this might be best to start with Lucy. This is really about how we measure sustainability. So I'd like, to probe that aspect too, to start with. So as a sustainability consultant, what, in your views are the ways in which historic buildings are more sustainable?

I mean the key thing is when you talk about embodied carbon, I think the fact that a building, a historic building, it is already there, it is already built. So actually ways traditionally when we talked about sustainability, maybe even, you know, ten years ago, if you look at energy and carbon it was all to do with the operational energy and carbon.

So, you know, the heating, the lighting, the cooling of that building. But actually, now it's become a lot more focused there is a lot of energy and the associate carbon that goes into extracting materials, production of materials, installing those materials to actually build a building. So in a way, you can say, the energy associated that has already been invested when you look at historic buildings and old buildings and by that means, they are actually inherently sustainable and that's something that I think is really important because actually you're not only done using virgin raw materials, but actually, you're extending them the life of that building, if you going to talk about demolition and rebuilding, a house, it reaches the end of its life or is there a way that you can extend the life of that building good.

Yeah, I think the key thing is the buildings, the building has got to be functional. That's the challenge. So there's a lot of buildings out there that may not meet the functional requirements of a client or a user. And if we've got to make that building work harder and be effective, you would have to make sure that any interventions that are made are reflected when you're sort of trying to measure that sustainability, because that does have an impact as well. 

If you're going to do an awful lot of refurbishment or remodelling of the building that can have a significant impact. And once you then add that into the potential lesser energy performance over time, you may then have a different sort of calculation or a different answer. But the key thing is to be able to measure it, to be able to give clients informed and sort of inform that decision.

There's an additional initial sort of layer to that which is working with existing buildings, historic buildings, and often listed buildings. There's also the balance that needs to be struck between the need to a reuse retrofit or the need to be sustainable, which is an agenda that is getting rightly higher and higher, but at the same time also the need to retain support significance, not lose significance, balance, change.

It's a very, very fine balance. That needs to be looked at on a case by case basis. And sometimes it's also a bit of a client education process where there are specific brief requirements that would call for certain approaches by the same time, either consideration needs to be brought in that need to be waived into the narrative for the project. And that's not always very easy.

I think on that point as well. It's that kind of balance we always kind of talk about. I feel like sustainability sometimes they talk about, just the environmental side of things. Yeah. Actually, if you're looking at the social side of things, I think there are probably pros and cons to both of them. When you talk about historic buildings.

And I think like James said and you're saying about, meeting the brief is, they tend to be probably not as interactive spaces. You know, you have more cellular spaces and how does that work for the people in the building? But also I do think if you look at where historic buildings are built, there's maybe a sense of more kind of community or there's a range of like you said, I think it's not just looking at that building in isolation.

It's talking about where that building is located. And I think, the things around permeability streets and things of how that should be built and that has an impact on sustainability as well.

Yeah. And I think most particularly when we come to our historic buildings, they tend to be at the center or close to the center of our settlements. And therefore they have better transport communications as well. Closer to the community. So there is the social and the economic aspect as well as the environmental. 

I wonder then, Lucy, if the tools we have for measuring these things capture those benefits of historic buildings or existing buildings sufficiently? There is, for instance, one architect campaigner who believes that the tools don't emphasize embodied carbon bodies’ energy sufficiently.

And currently, our tax system doesn't support the re-use of existing buildings like a VAT on conversion, whereas there is no new build. So is it to think the tools we have sufficiently recognized the benefits?

I think they're getting better. I agree. So I mean, as I said, the fact that we'd be measuring that kind of operational carbon for so long, I think embodied carbon side of things is still relatively new. And so, we use one clear LAT, which is a lifecycle assessment tool that allows us to start quantifying the embodied carbon.

And there are various tools out there. But I think, those tools would be a bit subjective in the sense that you know, we all sit there as a team and we'll sit with the architects and engineers and look at the different material builds up and we put that into the one click database. But I think that database still needs to evolve.

So there's still, the making sure that we're putting in the right materials, making sure that there's the information for those materials and so sometimes it might just be a standard build up. Some of them will have, what they call an environmental product declaration, which will go into more depth in terms of what their embodied carbon associated with that material is.

But yeah, I still think it's got some way to go before we get some accuracy, in those tools. But I think they're a good tool at the moment, especially at those early options and as James is saying, around that balance between a new versus old, you need to look at the whole picture.

So we need to understand what is the embodied carbon and be able to quantify that but then also balance that against the operational needs. But I would also say the social side of things, I think that's where we're lacking in terms of tools and being able to match.

Yeah, I would add there are other aspects to that too. The social economic sustainability where refurbishment of an existing historic building calls for certain techniques, certain methodologies to be applied which may have been lost or may lack and may require upskilling of the work force, may require opportunities for creating or supporting specialist artisan workmanship, restatement of traditional working methodologies.

That I think it would be helpful if that could also be somehow quantified and recognized in the process, because that's part of the benefits that arise from the refurbishment of a historic building.

Yeah, I agree. And I think that, we've been working on Manchester Town Hall and that's something they've been trying to do with identifying what skills and craftsmanship are needed, but then actually quantify, OK, so has there been apprenticeship schemes that have been set up as a result of that? Has it created employment within the area?

And again, it's just been able to kind of get those tangible bits that you can quantify. Is that.

Yeah, yeah, yeah. And the Palace of Westminster is another project which is very relevant. And in that respect, Very good, so it's been said that the greenest buildings are those that already exist. And that's a comforting thought, but probably not one we should be complacent about. 

So I want to move on now to discuss, not just embodied energy and carbon and no more uptake of Green Keels and such, but also the aspect of energy and use.

So the question really is, is the re-use of existing buildings always more sustainable and where are the limits? I think I'm going to start again with Lucy on this one in terms of, you know, that balance of embodied energy against energy and use in your experience and we'll come to James and Il’ic. But in your experience, what are the limits there?

What are the challenges of using existing buildings? And in most respects, are they notably not sustainable?

Yeah, I think it's a good point, and I think that goes back to that thing it's the balance between it. I think the issue you've got is which kind of historic building is that, what are the interventions you can do if you're starting with a blank piece of paper for new builds? There's obviously a lot more opportunity.

So I think that's really where the challenges come and as I said, I think there is always that switch now that because the grids decarbonizing because you've got new building regulations coming in, almost the energy in use is going to be a smaller factor in the whole energy carbon piece because there are mechanisms in place that are going to start reducing that impact.

And therefore, by a shift of magnitude, your embodied carbon has become more important because, I think James mentioned it, you're having to put in more materials if you're looking at putting in triple glazing from an embodied carbon point of view. That is worse. I think also we've had projects where, if you're looking at maybe a building that's a bit more cooling led, if you're then starting to only focus on the embodied carbon and you're actually, you know, really thermally insulating that building actually, are you increasing then your cooling demand for that building?

So again, it's just you can never look at those in isolation. You've got to look at the whole carbon piece. I think James would agree that's right.

That's really, really important. I think the mass in the form of the building can be quite key if you end up with a very deep plan building that's got lots of people in it and you're using it as an office. So there's lots of heat being generated from the equipment and the people inside you then sort of super insulate it because you think it's the right thing to do.

Sometimes it isn't because, as Lucy said, it’s cooling that building and you end up not needing to do that. So it's coming back to thinking about things holistically. And it comes down to windows I think windows are kind of the thing that allows the building to sort of be if it's not got windows is a box, isn't it?

It's horrible. So those windows are sort of fundamental to making it unique to the way of controlling the environment that they interface with the environments as much as you can potentially insulate sort of solid elements of the building, the windows are the really key events.

And also from a conservation perspective, often they are the easier bits to address as part of the refurbishment because often you've got existing buildings listed buildings, insulating to the outside of the inside is it not possible, not acceptable or undesirable. The windows can be targeted for specific improvements which in the example of The Old Admiralty building actually did more than one thing.

We had the imperative of the environmental control within the building. We also, very importantly because of the location, had a central London location right next to Trafalgar Square we had a very strict requirement in terms of acoustic control within the space. And at the same time, because it was a government department, we have the requirement for security and therefore looking holistically at what we needed to do and how we could bring all these briefing requirements.

Again, the brief within the design, in that particular case, the use of secondary glazing was the most suitable way to address every single one of those points in other instances, for instance, Somerset House, the East Wing refurbishment that we completed back 2012, it was agreed that secondary glazing would not be suitable for all sorts of reasons.

Clearly, one a listed building, the level of significance and the level of impact that would have brought would have been completely different and therefore a different type of approach was taken where for instance the natural ventilation or the mixed mode natural ventilation system was agreed to be more suitable to the needs of the client.

That brings us to a very interesting question which is relevant to a number of our projects, including again the Palace of Westminster and I'm going to direct this one to James. It is this constant dialog and sometimes tension between the principles of sealing the building and say saving the energy and recycling the energy from it on the one hand and naturally ventilating on the other.

Can you, James, summarize for us what the current thinking is on that from a purely environmental engineering point of view initially before we go back to considering the implications of that on a historic building, which is clearly a section of the whole retrofit building stuff.

From an environmental engineering perspective, the optimum ventilation strategy, I think for building is a mixed mode ventilation building. I think it's good from a wellbeing perspective. People like to be in contact with their outside environment. It's a much happier building, but you still have the ability to mechanically ventilate, and heat recover and control the amount of ventilation that you're putting into the building so you can maintain air quality, which is key.

It's something that's particularly at the top of lots of clients’ agendas at the moment with this current pandemic, air quality and some sort of guarantee of ventilation are fundamental. So you can do that with a mechanical ventilation system. But at the same time, if it's done intelligently and the installation should be able to detect that people can open windows and actually the mechanical ventilation then ramps back.

And so, you’re not wasting energy. You're allowing that natural ventilation to happen. That's the ideal scenario. And then you build in. That's what we'll be doing.

And you've described almost word by word what we've done, at Somerset House where we enabled the user to open the windows if they wanted. There's an element of benefit in enabling that kind of freedom, in enabling that kind of control. But the technology enabled us to install some sensors that when the windows were open, automatically cut off the cooling or the cooling into the space, which clearly adds benefits in terms of less loss of energy by the services working whilst the air is just escaping through the window.

And that mixed mode is and has been a success with that with the client so much that it's been used in other projects by the same client like the King's College London. It’s interesting because Somerset House was one of the first examples that we know of to achieve BREEAM excellent rating in a Grade I listed building and that was quite an achievement but in a sense, it's just the first step because these are examples that need to be taken and reutilized and used in other circumstances.

Yes very good. Is there anything else we can do to make our old buildings more sustainable? Is there anything that we've come across in our work where in addition to the physical measures, for instance, is it about the uses we apply to them? Is it the way we adapt them? Quite a few of the projects from your point of view, are they sure about adapting buildings to new uses and that gives them a new lease of life, which I think Lucy has already referred to do that’s also inherently sustainable.

What about building materials, there's a constant dialog about the sustainability or otherwise of traditional building materials.

Do you have any thoughts about that? This is maybe on for Il’ic to kick off with?

Yes. Yes. I think I think there's a paradigm in the sense that I think is shifting and needs to shift probably between the significance of the historic building and the importance of how we address climate change, how we address sustainability, and how we introduce more sustainability.. building materials can be part of that, but it needs to be supported by understanding what those materials are to start with, what are we working with?

Because working with a Georgian building is not the same as working with a modernist building. The type of materials, the way that materials behave the insulation that they provide, and the kind of comfort it provides is completely different. And therefore, the introduction of insulation, the introduction of energy and the introduction of other new elements within the building need to recognize this relative difference.

And in the case of existing buildings, particularly more modern buildings, where notoriously the level of the older, for instance, the thickness of the walls reduced dramatically, there is an imperative to rethink how we can address the deficit in the way that these elements behave.

Yeah, I think you're right. And I think there are maybe like two points to it. I think there's the fact that actually, we'll go back to that holistic thinking, well, how would we if we've got historic buildings and we've got materials a little bit in there, what are the benefits of those materials? 

So what we say and can we use high thermal mass of those materials actually as a benefit in terms of the internal conditions?

Because actually that's probably better than talking about stripping out these materials, replacing them again, I think, going back to Il’ic’s point, as well as the fact that you have to look at these buildings in isolation and you can't just start saying, right, let's put a load of timber or biobased materials into these historic or existing buildings. 

So I think there's also a piece on the industry and how do we make some of those materials more sustainable so when we're talking about, you know, concrete, unfortunately, is just a very good material for buildings.

It's not from a sustainability point of view, but the industry is already looking at, OK, well, how do we then make concrete more sustainable? 

Because actually there isn't that you're never going to get away from using that in some form. So I think there's a bit of a piece about that as well of how we as sustainability professionals and architects and just how we engage with industry and how we kind of push some of that innovation and forward thinking around the materials that we could use.

I'm often concerned by one of the elements that racks up the carbon footprint of the construction industry. Not only is the creation of the material to build, but also the transport is the fact that we source materials for construction from all over the place. It's a little bit like going to the grocery and buying bananas from the other side of the world or indeed apples from South Africa.

When the UK used to be the orchard of Europe and how do we translate that into a better knowledge and an awareness of the local materials. 

What is typical of a certain region which used to be the normal approach in construction.

Very good. I'm going to finish with one question, which isn't scripted, but what does the future look like? 

What do you think in terms of your personal work and maybe a broader picture? 

What do you think the future looks like in terms of the adaptation of buildings for sustainability reasons in this, in the UK, in your experience… 

Ili’c?

I think my view is that it looks far better now than what it used to, say 10 or 15 years ago. The sustainability agenda has clearly gone up and that is positive. I want, to use that as a positive opportunity to challenge the way we work, to challenge the way we look at and work with historic buildings and adapt them in a way that meets the wider agendas that are no longer/ that can no longer be ignored.

We need to address them. We need to address these issues. And, you know, the existing built environment in the UK only is between 20 or 30% of the whole built environment. So we need to address this with an eye to the bigger picture.

I'm not sure I'm feeling as positive as Il’ic, but I think we're getting better at looking at sort of non-residential buildings I think, there's much more understanding. There are clients of different drivers and different pressures to try and reduce the carbon impact of existing estates. You know, universities have got students they're expecting their university to make an impact in terms of reducing carbon emissions and why the clients have got other drivers to do it. 

But a huge amount of the buildings in the UK are residential buildings, whether they're mostly owner occupied or not. And they’re a real challenge to try and incentivize people to invest in something, an interest in, you know, what's going on in the wider world at the moment in terms of the sort of the terrible things happening in Ukraine and the sort of fuel crisis that's happening that may start to drive things differently.

And it's interesting. There may be a positive aspect to that. The worry is that we will find other ways and fracking will stop happening and we'll be dragging more and more fossil fuels out of the earth. But I think that's the real challenge, trying to sort of engage with people who are sort of in charge of the vast majority of the property in the UK is really difficult because you're looking to them to invest in something that they do not really seem to particularly to benefit from, but it's something we need to do.

Yeah, I'm probably somewhere in the middle. I think I agree. You know, for me in the last ten years of my career, I've never seen sustainability so high on the agenda, which is a really positive thing. I think there's a lot of people that want to do the right thing, and I think we're seeing clients even from if we talk about existing buildings, I think from sustainability and possibly the whole thing with COVID that clients are looking at how they adapt their existing assets, and does that mean consolidating, does it mean repurposing the assets that they've got? And I think I agree with James, the challenge that we have in terms of owner occupied space is if you've got owner occupied buildings is a lot easier because they're seeing the operational and the cost savings versus just investing the capital cost and then selling that asset on.

I think the main challenge is just that the ‘want’ is there. I think it's the ‘how’ to do it and getting over the challenges that come along the way. So I think for me it's understanding we need clients that are going to drive it. That's clear, and brief. I think the three things for me are cost, time and planning, I think the cost element there is still this perception that sustainability costs more.

And I think that's something that we need to kind of understand more of the process. I think the time when we talk about designers I think we're always rushing to deadlines. And I don't think we factor in, when you look at some of the projects we've worked on that are going for net zero, that are going fully established credentials, you need to build in the time in the program to actually understand what that means and deliver that.

And then I think there's loads of, I think, industry and you think you've got things like the London Energy Transformation Initiative, you've got industry groups that are pushing the sustainability agenda in this sector. But I think the planning side of things, there's still that conflict. When we talk specifically about historic buildings and sustainability, I think there is still a bit of a disconnect.

And until we can kind of resolve that and I know that we do a lot of work in Westminster and they’re trying to move forward with that. But you're still coming up against hurdles when you're trying to make old buildings more sustainable. I think there's got to be the mechanisms in place that then allow you to do that.

Great. Thank you. Thank you, Lucy. Thank you all three for your insights. I was told recently that an increasing amount of our work as a practice in the UK in particular is on historic buildings so I'm sure the sustainability aspect will become an increasingly more important aspect that works for reasons that James just outlined just now.

Thank you, all three.