Why grow a building?
Interview with
Could you grow a building, and would you want to? These are the two questions heading up this week's programme, posited by Northumbria University's Professor Martyn Dade-Robertson...
Martyn - My name is Martyn Dade-Robertson. I'm Professor of Emerging Technology at Northumbria University and I'm also the Editor-in-Chief for the Cambridge University Press Journal by Technology Design.
Chris - You're making a very auspicious start, Martyn, because this is the first of these programmes we're making and it's very exciting because the question that you put forward, if you'd like to tell us what it is, immediately got my creative juices flowing. So tell us what the question is you think we're going to address in this episode.
Martyn - Yeah, so the question is, can we grow a building? And then there's a sort of separate bit to that question is, and would we want to?
Chris - Well, let's start with the first one then. Do you literally mean as in growing a building out of the ground? Or do you mean growing the component parts of the building?
Martyn - Literally, yes, in the sense that that's the aspiration, although we have to break down that problem into smaller parts. So it does make more sense and the way we're tackling it in the journal is to look at those parts separately. But the analogy that I give often to our group and the people that we collaborate with is a tree. So the idea that we construct in the way that a tree constructs itself, so using only the natural resources available to it in its immediate environment through the soil and so on, and then able to self-assemble a really complex structure with multiple different functions and able to survive and then maybe even live after it's been constructed. So if we think of a tree, think about a building constructed in that way, that would be the sort of the grand ambition.
Chris - It's got foundations, roots. It's got structure, which is the trunk. It's got layers, the stories, because you've got leaves, and then it's got solar power, as well as drainage and water.
Martyn - Drainage and water, yeah, a whole plumbing system built in. And it does it with very little materials. So cellulose is the same stuff that's used in the trunk as used in the leaves. Albeit in different mixes and organised in very complex ways, but it provides us with a sort of template for how we might think about construction in the future.
Chris - Obviously, we do use timber in the construction industry, and it's one of our oldest building materials that we as a race, species have had access to. But what do we need to do then in order to realise the aspiration of buildings that do grow themselves or all the component parts of buildings grow rather than get made?
Martyn - Yeah, we absolutely do. So we already have the principles of using biology in our built environment. So not only trees, of course, we've also got things like limestone, which are calcificated remains of sea creatures and so on. So we're used to using those materials. But we have to think about them in a slightly different way. So we usually harvest the materials after the organism that created them has died. And so we're taking what we're given, and then we try construct our buildings around what those materials will do, often by processing them quite heavily. But to think about a building as something which has grown, we need to think about the building being assembled while the organisms that is creating the building are still alive. And that involves thinking about how we interact with that biology to make materials that are suitable for human purposes, but also allow the kind of biology to do its thing.
Chris - You said in opening, would we want to do this? What would be the benefit of that? Why would we want to do it?
Martyn - If we think about the tree example that I gave again. I mean, the first thing that's most often on my mind is that the tree assembles itself whilst it sequesters carbon dioxide. And that's the complete opposite of the way that we construct at the moment. So that would be a big goal if we can get to a construction process that sequesters carbon dioxide as a building is built. There are also the benefits potentially of self-assembly, so materials that can organise themselves. So we don't have to go through the heavy process of constructing and removing materials around from place to place to make. So again, the tree example is one where we're using only local resources. And then there's a sort of idea there as well, that rather than having to maintain our buildings, the buildings themselves will maintain themselves. So living organisms are adaptable to their environment. They're capable of changing and responding to different conditions, things like self-healing. These are things that our buildings currently can't do. So that would be the kind of ultimate aim, if you like, of a truly biological architecture that it could do all of those things.
Chris - How close are we to being able to realise any of this? Because it sounds fantastic, and you can immediately see why this is an attractive option. But it also sounds quite unrealistic in the sense that buildings work a certain way and to live in a tree. Yeah, I've heard of tree houses, but there are limits.
Martyn - Yeah, there are definitely limits. And so there are lots of limits to the current technology, but some of it is a little bit closer than you might think. So just to give a couple of examples, there is already a company that makes a type of concrete, for example, that has bacteria spores, like the seed form for bacteria embedded within the material, so that when it cracks and water gets into the cracks, the bacteria spores germinate, they come alive again, and then they produce calcium carbonate crystals to heal the material. So this is a viable option. It's a biological material, and it has that capacity for self-healing. There are other examples as well. Mycelium, which is the root network of fungus, can be used to make a really good bulk material very quickly. It's often thought of as being a good acoustic or thermal insulator. So we grow that material to give us particular material properties and characteristics. At the moment, we grow it in the lab, but there are factories that grow it as well. And it creates, as I say, a really robust, often quite fireproof, mainly insulation material. So there are examples where we've got materials that are actually a little bit close to real construction that might not reveal the whole vision of a growing building, but where we can certainly grow parts of our building to really, I guess, quite tight specifications.
Chris - Recycling though, presumably with a grown building, if nature gave it to us, nature can take it away. Now that has a pro and a con aspect to it, because wood going mouldy and rotting is notoriously a problem. But it makes the recycling headache go away, presumably, doesn't it? Because at the moment, we are discovering to our cost that we should have thought about how to recycle materials earlier in the day than we often did.
Martyn - Typically, we design our buildings with a predicted 50-year lifespan. And of course, if we look into our built environment, we can find plenty of examples of buildings that have been there for 100 more years, and often a lot longer. So what we don't want is our buildings to biodegrade at the wrong time. So this is an issue. How do we allow our buildings to be biodegradable when we want them to be? I think there's also quite a lot of work to be done in things like the way we package up building materials and move them onto site. And one of the big issues of constructional waste, actually, is the amount of packaging and protection that we put our building materials into. And this is particularly true in the context of off-site manufacturing of buildings, for example, where we're doing a lot more now in factories where we're making very precise building components, but they have to be protected and then moved to site. We think this is an area where biology can help as well, where we can have these materials which are much more biodegradable and therefore sustainable. They don't add waste into the environment in the same way.
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