Director Andrew Waugh and associate Rachel Crozier discuss working with timber and other low-carbon materials and the challenges involved in changing the way we build.

Rachel Crozier and Andrew Waugh present a selection of samples of low-carbon materials in the mezzanine meeting area. Playful wooden models surround the space.

Shoreditch has always been home for Waugh Thistleton. Founded in 1997, it started life out of co-founder Andrew Waugh’s flat on Charlotte Road before moving to Rivington Street. Today, the practice is on Leonard Street, in an office that is surprisingly small at first glance but opens up to reveal a curated selection of materials: various timbers, rammed earth and more, that greets guests before they find themselves in an open-plan mezzanine meeting area. A large wooden table is surrounded by wooden scale models, some of which form playful dioramas depicting modular construction.

Here, Rachel Crozier, who joined the practice in 2010, and Andrew Waugh explain how new ways of building and furthering a low-carbon material palette have informed the practice and continue to shape its future.


100% wool ‘Divina MD’ upholstery from Kvadrat used for sofas at 6 Orsman Road.

Waugh Thistleton Architects has become closely aligned with cross-laminated timber (CLT). What led you to this and how does CLT inform your practice today?

Andrew Waugh People call us ‘timber architects’ — we’re not timber architects, we’re low-carbon architects; architects that understand the significance of the impact of our actions. And we see timber as the only viable replacement for concrete and steel.

I applaud other people’s investigations into low-carbon materials but I do often wonder if that’s more a way of being distinct than a way of looking to reduce carbon, and that does frustrate me. There’s been lots of work in other fields, spraying mushrooms with robots and all the rest of it, but that’s not going to solve the urban housing crisis. There is really great work being done with other bio-based materials: straw bales, hempcrete and more — which I get, but what we actually need is an alternative to concrete and steel. What we need to be doing as a society — most definitely as a profession and imperatively as an industry — is vastly reducing the amount of those materials we use — specifically concrete. We have a viable alternative at hand, and it’s timber.

And beyond timber?

Andrew Waugh Our ambition lies beyond timber, yes. Replacing plasterboard with clayboard, replacing concrete with rammed earth, for example. For us it’s about demonstrating that these are exciting opportunities, not hair shirts. There’s been that attitude towards sustainability that it’s like muesli without the raisins, a bit holier than thou. Whereas in fact, it’s none of those things: it’s transformative, better for you, and really tasty.

Rammed earth is an interesting one —why, when and how did you work with that?

Andrew Waugh It was used for Bushey Cemetery, a project that is only designed to last for 60-70 years until it’s full and then the buildings will no longer be necessary. At that point, they can be ground back down into the earth from which they came.

Rachel Crozier Rammed earth is quite complex and unpredictable, and as a natural material it does break a lot of the rules with regards to the protocols for working on site and inspecting things. We started with one subcontractor and they built a test wall up at the farm on the site, but it didn’t work out as hoped. Then we used a contractor called Earth Structures who did pull-out tests to see the strength of the wall. It’s not a very precise thing: we had piles of different materials dumped on the ground. A tiny Bobcat digger took mini scoops and mixed the soils and gravel together. The process wasn’t controlled. It was impossible to snag. It’s a natural material with pockets of clay which meant that when it dried, not only did the colours change, the pockets of clay would burst too. But it’s also the most beautiful material, rich with layers and its qualities really emerge as it dries out with these rich red and yellow colours. It also looks completely different when it’s wet — it goes quite dark — and that’s ok!


A selection of core samples of rammed earth was produced to experiment with colours and to test their strength for the prayer hall walls of Bushey cemetery.

How do you condense this new knowledge on materials – all that data – into a library and make it into a resource?

Rachel Crozier We have a magic box for each project. In them we keep our samples and a project’s material palette and how those materials fit together. It’s quite important to us and it’s a physical memory of that project that lives on in our office. It’s just as important as the details that are drawn that live on our server. With the project at 6 Orsman Road, we looked at clay for the reception space and examined clay colours. So in the magic box, we don’t just keep what we ended up with, but retain a few things that tell the story of that process. The final finish is as important as the lessons learned from that project and the box of materials can be used to tell that story to others in the office – not just where we ended up but how we got there.

Andrew Waugh We get sent lots of materials as well, from everywhere — it’s really very exciting. In the past couple of weeks we have had bamboo samples from Bali, CLT samples from New Zealand, particleboard from Luxembourg. When a new CLT manufacturer sets up, they tend to send us their samples. When somebody is talking about engineering a new type of timber, they call us up and we sit down with them and go through it. We learn about what they’ve done with the material and we tell them what we need as specifiers in order to be able to use a material: the technical approvals, the tests that need to be conducted. We ask where their material comes from, what their certification process is. We try to understand how their supply chain works; what their drivers are for producing that material; the processes of manufacture involved; the adhesives; where the timber comes from, that kind of thing.


21 series Bocci hanging lights used to illuminate the staircase at 6 Orsman Road.

What would I find in the Bushey Cemetery magic box?

Rachel Crozier A lot of rammed earth! There were lots of variations in the patina we could test with it. There are some natural tiles that were used in a prayer hall, some stained larch cladding for the mortuary, and also larch glulam, used for a colonnade that links the prayer halls together and frames the procession that is so important to the funeral process. How we stained the wood was really important to us because we chose larch that weathers well — we didn’t want to choose a highly toxic product that needed to be repainted or would peel off, but at the same time, we didn’t want larch that would look patchy and uneven for five years. We stained it with some flooring product and kept samples of the staining.

Inside the box is more an indicative palette rather than an exhaustive catalogue. We don’t keep taps or door handles or signage etc, those are not interesting to us in the same way. If it’s off the shelf, then it’s probably not going in the box. If it’s a natural material or something we developed and made decisions on, then it’s going in.

Besides going into a magic box, how do you address the afterlife of materials?

Rachel Crozier We are very determined to find homes and uses for materials but that does often require a re-education of clients and contractors — everyone involved — as we are persuading them not to rip off timber cladding that we’d like to rehome. It should be taken off carefully.

We are looking at the way CLT buildings behave throughout their lifetime. We know this to some extent by talking to people, but we’re keen to explore and record this further. It’s good to get that data quantified. With a project on Whitmore Road, we’re looking at putting sensors into the building to measure the temperature and how that varies throughout the day and night and through the seasons. There’s a concrete office on the lower ground floor and it will be interesting to compare how different areas of the exposed structure behave.

Andrew Waugh For a long time, perhaps even decades, the timber industry has had an attitude of ‘well we don’t need to do that’. It’s quite disparate in the UK — we have such a small timber industry relative to other countries that we haven’t had much research or funding into timber construction. That’s a reason why it is much easier for us to work outside the UK as not only do they have more ambitious legislation and cultural attitudes towards sustainability, but they also have much more progressive and active industries around timber. We don’t have many trees so we don’t care about trees, is how it seems in the UK, and that’s a tragedy.


Larch decking forming the timber boardwalk that stretches from the car park to the reception of Bushey Cemetery.

What excites you about working with timber and what do you/we still have to learn?

Rachel Crozier It still surprises you how quickly and easily it goes up — a seven- storey building can go up in five weeks. It smells of the earth. Being in a timber structure that really smells of timber, rich with that earthy-ness, gives me the most pleasure and it’s so different from walking into a concrete-framed building which is so cold, it doesn’t give you any of those emotions at all.

Andrew Waugh We’re still really building concrete buildings with timber. Yet I feel there’s a lot to learn about how the material can begin to inform the architecture to a greater degree. We are still right now riding a horse in front of a train. The industry needs to transform very quickly.

Rachel Crozier It’s also hard to educate contractors and a design team that they need to coordinate everything before it arrives. The team that puts together a CLT building is very important. The process involves a high degree of craftsmanship, taking a hammer out of their back pocket and pulling towards you a huge panel hanging from a crane, holding onto it with a hammer and slotting it into place.

Andrew Waugh We’re a country without a decent timber tradition and you can see that the aesthetic of timber buildings that’s driven in places like Scandinavia and Switzerland is really enticing. They have a timber tradition and vocabulary that we don’t have in the UK. We have mock-Tudor, great, but we don’t have that reference point for timber. I know architects in Switzerland who have aunts and uncles that are carpenters; there’s a cultural connection to that trade. From that comes an architecture allied with craft and from that craft you can learn how to mass-produce.


Resilica recycled vanity tops, used in reception building WCs on various projects.

How do you bring that culture into an architecture studio?

Andrew Waugh We do trips to timber factories and forests as a practice. We try to encourage our clients to go to timber factories too. If you want to build a timber building with a client, all you have to do is take them to a timber factory. That’s it.

What gets them over the line?

Andrew Waugh The thing that convinces clients is seeing the production of engineered timber; that closeness to a natural material twinned with the level of sophistication and scale of how it is managed. It’s like walking through a really high-tech environment that smells pine fresh. It’s a contradiction in many ways. You could meet a forester, and they could be cutting down trees that their grandparents planted for them and they’re growing trees for their grandchildren to cut down in their place. It’s a very close relationship with the soil and with the environment. But there is an ability to build buildings at scale from that responsible process, too.

It’s fascinating that we are at that point as a society where we have realised that we need to reconfigure our relationship with nature through natural products. And I think there is space for technology within that relationship — space for sophisticated technology — but understanding our relationship with timber, trees etc is a vital part of understanding how we move forward. Beyond carbon, the extractive nature of how we build is also something that we need to re-interrogate.

What material are you excited about using moving forward?

Andrew Waugh I’m really keen to understand how we can use timber more efficiently. The frustrating thing is that, in Europe, we burn more than half of the timber that’s cut down. It’s used for bio-mass, which is crazy. We are still looking at ways we can use the tree more efficiently.

We do a lot of work with LVL (laminated veneer lumber). The development of softwood LVL is really interesting, as is the development of OSB strandboard, as we’re learning how to use lower-impact adhesives and formaldehyde-free adhesives. Once we really start to understand that then we can use the maximum amount of the tree.

The way we currently machine timber is quite two-dimensional. It’s like making a model. We’ve been working with a timber manufacturer in the U.S. using 3D CNC machining to produce timber connection details, looking at Japanese carpentry detailing and seeing how we can use some of those precedents in a contemporary setting — that’s what excites us.

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