'Sustainable cities and tall buildings' report part 1

Image: contributors joining in the Future Cities Forum debate on 'Sustainable cities and tall buildings' at EY, with Marcus Richards, EY (standing)

Future Cities Forum's 'Sustainability and tall buildings' discussion event was hosted by EY at its London offices, situated by the southern bank of the river Thames with views towards the City of London with its ongoing programme of tall tower building and the Tower of London, where planners are considering the impact of sky-scrapers on heritage.

The discussion had a focus on balancing the economic necessity of density with the urgent requirements for sustainability, heritage preservation, branding of city districts and social equity. Contributors debated whether "sustainable tall buildings" are a technical reality or a commercial myth.

Mace Construct detailed a "world-first" approach at Euston Tower. Instead of traditional demolition, the 1960s concrete tower is being "sliced" into slabs for testing and potential reuse. This industrialization of deconstruction aims to de-risk the carbon and safety profiles of major retrofits.

Other contributors to our discussion were Fred Pilbrow and Andrea Marini of Pilbrow and Partners, Austin Wickner of Ridge and Partners, Balazs Bicsak of Price & Myers, Stuart McDonald and Shaun Tate of Mace Construct, Tim Downes of British Land, Dr Paul Toyne of Grimshaw, Alex Kerr of developer EDGE, Matthew Wooding of LDA Design, Marcus Richards and Siane Marshall of EY Parthenon, and Arash Rajai of RPC LLP.

In the first part of this report, we have included contributions from EY, British Land and Mace Construct. The second part of our report will follow shortly.

Marcus Richards, Partner at EY Parthenon, began the discussion, talking about how tall buildings are inherently complex by nature:

'In particular, they are capital-intensive and of long-duration but actually that is true of all broader place regeneration. Undoubtedly, and I dare say regrettably these buildings will in further years ahead have to be delivered in an environment of fiscal constraints and economic and political volatility.

'So I thought I would touch on three principles that might help to kick the conversation off. We might well build on these as we go. Firstly, I wanted to talk about the link between economic growth and financial viability, and drawing on the work that I've done of late. Those two factors have become ever more intertwined and dependent on one another. Large-scale regeneration is inherently dependent on the economic growth that it creates.

'A fundamental mechanism that we've worked on as a team within EY to ensure that we can improve the financial viability and close inherent funding gaps in these schemes. I think the UK, but also across Europe, we've seen some really fantastic and innovative examples of value-capture mechanisms that can help close certain demand on the public purse, but ultimately make these schemes more viable and more financially sustainable. From the perspective of tall buildings, I think they play a really critical role in that equation. We know that tall buildings, when delivered effectively and appropriately, can act as magnets for economic activity. They can increase density, concentrate demand, and I think they can undoubtedly accelerate place renewal.

'I think that if I look at the experiences that I've had, and I go back to the example in Victoria North, Manchester, that the concept of tall buildings being a really important part of that comes from the ambition of significant and strategic place renewal, but it actually plays a really important role in the financial mechanisms and engines of how these schemes work. And so I guess maybe from a layperson's perspective, one might assume that tall buildings are a response to economic growth. I might argue actually they are a catalyst for economic growth.

'Secondly, I wanted to acknowledge, and this is undoubtedly true of what we're observing happening in London around us, how concepts of tall buildings work best when they are integrated into a system of place rather than being seen as standalone assets. And so by that, I observe that means better alignment with public and social infrastructure, transport infrastructure in particular, integration with energy and digital networks, connections to public realm and amenities, and playing a key role within the fabric and character of wider spatial strategy. The reason I think that's really, really important is, again, going back to examples where you see these big, large-scale place regeneration schemes taking place, there is a heavy dependence on the development of social infrastructure and public assets that ultimately are becoming an ever-greater financial challenge to deliver. And so if you have at the core of these schemes, assets that are developed, that can make those public and social assets more viable, that is to the greater good of delivering these schemes at scale and pace.

'We've seen that first-hand in the examples of Battersea and Canary Wharf just down the river from here, and it certainly was the case in Manchester where we've worked as well. I think I've tended to now look at these not as being a primary focus on a standalone asset with some development that goes around it, but actually a coordinated urban system in which that is one component of a more complex network and system, recognising the importance of density and how that supports viability and how viability then supports the quality of public realm.

'Thirdly, I guess taking it back to what my role is and the clients that I serve, I want to touch on the role of the public sector in all of this. I'll maybe start with a personal reflection on that, that I actually think the job and role of local authorities in a conceptual sense is an incredibly, incredibly difficult role. And I have great admiration for the officers and politicians that take on that role admirably.'

Image: Victoria North, Manchester, courtesy of Manchester City Council / FEC

Marcus continued:

'There has been an evolution of that role that has happened without due recognition, with the fact that now local authorities are no longer, as may have been the case decades ago, seen as a primary deliverer of capital activity. They are seen more as an economic orchestrator, and I think that is an incredibly challenging role, and I think they do that in most cases really, really effectively. I think the public sector clearly plays a really important role in helping create the environment for this sort of development, so obvious things like providing planning certainty, government certainty, clear spatial frameworks, long-term placemaking strategies and vision.

'I think, again, touching on another topic of today, a really clear and coherent vision for sustainability of the assets that's involved in creating. I think that where you see these sort of schemes working most effectively, Battersea is a great example, Victoria North is also a great example, is where it is founded on true public and private sector partnership. I'm going to close just with a slight reflection, which again I think is on topic, with the theme of today. But as we are in London, I grew up in London, and I love London. Most of my friends have now moved out into suburbia, but I seem to want to move closer into the centre, and I'm sort of fascinated by the place. And I think if I sort of reflect on why that is. Part of it is because I think London is, maybe I will say unique, but certainly in a unique cohort of cities that I think manages to balance history, heritage and growth and innovation so effectively. I can't really think of many places on earth that does it more effectively than London. This might be familiar to many in the room, maybe less so to some of your listeners, but I've always been slightly fascinated about the quirks of municipal government that shape the city around us, and there's probably nothing more true of that than the London View Management Framework, which obviously dictates how particularly tall buildings, tall developments can be undertaken within London.

That was first established all the way back in 1902, which I find kind of remarkable that it was first considered as a principle well over a century ago, before the concept of tall buildings had really begun to take hold in London. And as many will be familiar, it protects views from places like Richmond Hill and Parliament Hill in terms of what you can see of some of our wonderfully historic buildings like St Paul's Cathedral and Tower of London as well. And many will be familiar with the fact that it actually influences the design and fabric of some of the buildings, so famously Leadenhall, the cheese grater, was designed in that particular shape, partly so as it didn't inhibit on some of the principles of the London View Management Framework.

That is also very true of the Shard, which obviously from some of the windows you can see sort of dominates the skyline of certainly this part of town, but probably London more generally. And I recall that when the Shard was first being proposed as a development and ultimately approved, I think it ultimately took an intervention from John Prescott at the time to push that through. There is great debate around whether that was going to, you know, phrases like tarnish our skyline. What I would argue, and despite me being a traditionalist, I would label myself, I think it is a great example of how actually that has complemented our skyline and has managed to blend wonderful assets like St Paul's Cathedral, something that will stand the test of time, I'm sure for millennia to come, with the most modern form of architecture I think is now part of the character of our city.

Image: CGI of proposed newly designed Euston Tower, courtesy of British Land / 3XN

The conversation moved on to discuss a 1960s building, the Euston Tower, which is being part built, part retrofitted by British Land.

British Land is exploring the future of Euston Tower, which was built in 1970 and has been vacant since 2021 – to create a world leading science, technology and innovation building and public realm for Camden and the Knowledge Quarter that inspires, connects and creates opportunities for local people and businesses.

Director, Tim Downes said:

'Euston Tower is a 1960s concrete office tower, circa 36 storeys tall, formerly known as the Rockwell Tower, home of Capital Radio. It was designed at a particular point in time when people were obsessed with cellular offices. The open plan, collaborative floor plate was not a thing that was in people's minds and it has got a floor plate which is somewhat constrained. So should the first point of call, if you were going to redevelop a building like that, because it's now 50, 60 years old, be expanding the floor plate?

'However, it has been put together in such a way that it has so many technical constraints, not just in floor to ceiling height, but also in how the concrete was physically poured, that by the time you go down the route of a deep retrofit to chop and change and cut and carve this building, you end up with basically a piece of Swiss cheese in concrete, which proves not to be financially viable for us. It takes far too long and almost generates as much carbon as building a completely new building. We had to have a completely different approach to this.

'So the new building, which I've described as a retrofit of the existing, but 70% of it is new, so there's quite a lot of demolition going into this building - we looked at whether we could actually reuse the concrete by cutting up the cast-in-situ slabs to create precast slabs that could either go back into the building or be reused somewhere else. This was not the form of demolition that John F Hunt, who's our demolition contractor, were familiar with or who hadn't been asked to do this previously, but they devised a way of effectively chopping up the building into slices that will enable a poured-in-situ, very complex 1960s building to be reused.

'This seemed like a good idea on paper, but then how do you prove the hypothesis? We took a test piece of concrete slab, so about the size of this table actually, cut out a slab from the first floor. It took quite a while to do this and then lower it down. It was sent to the University of Surrey, which has a materials testing lab, and they tested it in every which way you can imagine to try and work out how strong this thing was going to be, and whether it had viable potential for reuse in the future. It actually broke the laboratory floor, so the cracks appeared in the laboratory floor before cracks appeared in the slab, so that gave us confidence that yes, if you can industrialise the process of removing these slabs from the building, then there's potential in this idea.

'The next question was then, how do you industrialise it? So between John F Hunt and Mace, they actually looked at how you would take the building down, rather than just taking a sledgehammer to the top of the building and munching it floor by floor. The idea is to basically slice it up into larger slabs, say the size of this room, lower those down by crane, and when you get to ground level, then slice them up in a cleaner, more controlled environment to create these concrete slabs that can then be reused. So this was a test piece for us.'

Image: CGI of lower floors of the remodelled Euston Tower - courtesy of British Land / 3XN

Tim continued:

Lendlease came along and gave us a new 25-year warranty to put the facade back on. Not possible at the Euston Tower! The glass is 50, 60 years old. It's got some nasty coatings on certain parts of it. So we worked with Saint Gobain and Pilkington to develop a methodology for crushing it and rather than just putting it all into road paint and kind of like recycling it, upcycling it back into the float line. So previously, what we'd been told by Saint Gobain was that we can't solve the float line. We risk contaminating the glass by putting old glass back into it. This is not going to be possible. We worked quite closely with Arup, who then produced a paper that said, actually, I think it can be done. Saint Gobain said that they would test it for us. And they devised a way for us to take about 80% of the glass that's in the existing building out and for it to go back into recycled content to make sure that it goes back into its highest value use.

'The same principle there stands for the aluminium that's coming out of the building. So it's covered in aluminium extrusions. We don't want those to go into Pepsi cans. We want those to go back into the highest grade of aluminium that they possibly can. So with the concrete, the glass, the aluminium, to some degree, the steel, we've created pathways for all of these products that are coming out of the building to make sure that the value remains high and they remain in the built environment. As part of that, we need to secure warranties from our contractors. We need to get insurers comfortable with the idea of it. And we need to create a provenance and a paper trail, if you like, to show where these materials have gone to.

Tim was asked whether the building would have to remain flexible for use or could it be used exclusively for laboratories?

'In its existing form, it does not work for science and has limited future potential, hence the amount of demolition or deconstruction that we're putting into it. We're taking out all the floor plates, regrading them with less floors, up higher floors, ceiling higher, so we have flexibility to incorporate laboratories in the future. It doesn't mean it will be labs. It's about creating flexibility. You know, we have some laboratories at Regent's Place, which is the campus in that area. But it's about creating the flexibility and the capacity in the building to make sure that it can be laboratories, it can service AI and whatever their requirements might be, or you can service any type of workspace in the future.

Image: Euston Tower at Regent's Place on right of picture - waiting re-modelling by British Land

Mace Construct's Project Director for the Euston Tower, Shaun Tate commented at the discussion:

'I think it's actually a really good opportunity to break the cycle of the way things are done traditionally. Because we've got a massive challenge in construction around productivity, and we're always looking at how we can industrialise the construction process. So on this building, we've been given an opportunity to look at how can we industrialise the deconstruction process. So what we're doing is we're working with Hunts to look at where we're going to put springs around the tower, five storeys, and the way that you often create a building up, we can do the opposite, down with a descending spring, which enables us to create other efficiencies, which we'll go into right now.

'But what it means is that by putting up a slightly larger crane, as Tim says, we can actually count the number of things we need to deconstruct. So how many pieces are we going to break the building down into? And by doing that, it means we can measure it. We can be very, very precise about the amount of time it's going to take. The safety that it enables us to, you know, safer ways of working, rather than demolishing 36 storeys in the air, we're going to be deconstructing and doing the higher risk activities at ground floor level, away from height. So whilst it might be different, whilst it may be the first time it's been done at this scale, it actually, in our view, it de-risks the operation, and it brings more certainty. So because we're just thinking about it in a different way, it means we can't just do what we've always done. We have to find new ways of working, and actually when we explore those new ways of working, we think why don't we do this all the time?'

Image: EY's offices at More London in Southwark with view to Tower Bridge