Samples kept by the practice can alter a project’s direction, finds Tom Whittaker of David Kohn Architects


Agnese Sanvito

Established in 2007, David Kohn Architects has been in its premises in a 1970s office block on Camden High Street, north London, for the past five-and-a-half years. On the same floor are fellow designers Níall McLaughlin Architects and Cousins & Cousins. There is a large main studio plus David Kohn’s own office, which also houses the practice’s print library and doubles as a meeting space for larger groups and clients.

Teams of people within the office, alongside their project work, manage different aspects of the office such as IT or the print library. A designated member of the team acts as library manager, moving project-specific reference books into the studio and back to the office on a monthly basis, keeping the roaming library fresh and relevant to the projects in hand. Part of architect Tom Whittaker’s role, as a member of the design working group, is to manage the samples and material resources.


How are your materials organised?
There are three elements to the materials library.We have a wall of archive boxes of materials sorted into categories. At the beginning of the project there might be a research box of materials from which the palette of materials is developed: the incubator for the project box. Each current project has its own box, labelled with the project number and name, and contains all the samples that have been signed off by the clients. It’s understood that all the material has to be returned to that box as a living record of the project.

Each project lead is responsible for the contents of that box and once things have been rejected for use on a project, it’s best practice to either return them to the archive or remove them from the office to cut out clutter.When a client comes into the studio the contents of the box can be laid out with the model to show where the project is at that point.

In the main studio, big working models are set out with a collection of samples around them. People can touch the samples and be aware of their fragility; wear over time and permanence are of interest in the materials the practice uses. Architects can see how light falls on the materials in different conditions and see what works.


Stone model for a lobed student accommodation quad for New College Oxford. Matthew Volsen: “This has been made from Ancaster Weatherbed limestone, quarried  in Cadeby, South Yorkshire. We are hoping to use it  for the facade of the building, with a lighter, pinker stone to frame the windows. Limestone, although not this particular stone, is quite prevalent in Oxford. The office has used Ancaster Weatherbed stone before and it has traditionally been used in large buildings, as an ashlar, facing material. Here it will be CNC-milled to form the curves. The contrast in its colour stops it from being quite so homogenous and gives it a certain playfulness.”

What happens to the materials at the end of a project?
There is never a time capsule or a locked archive for a project. We have an offsite archive for models, but it doesn’t include samples. In a project box there might be ten samples, of which two or three are signature to the project. Those will stay in the office and be moved around to various other projects. Every year manufacturers’ catalogues are updated so we will get a new or more technically-advanced version of a sample that then finds its way into other projects. With every project there’s a degree of freshness; it might not be finished for eight years so we’re thinking both about how it fits within our practice’s history and how it will still be current.

David’s very interested in the projects in the office having a reference to architectural history and in that, the projects can start to reference each other. So the samples for a project from ten years ago are still alive, but among other projects. An encaustic tile – a hardwearing cement tile – was first used in a project in Barcelona but we’re now seeing iterations of that material on a lot of our other residential jobs. We’ve had suppliers that we like, and ways of working with particular types of materials that we like, and those are revisited regularly.

Open Asset is our online archive for every project, including ones that never got beyond the render stage.It’s been prepared by an archivist and contains initial  sketches, models, renders, presentation drawings, construction images and the details of the materials that were used, photos and a description of the finished project. It’s searchable, which is easier than going through a lot of boxes of materials. For example you can search for timber and it will bring up all the timber products that the practice has used. As a staff resource it’s very useful, it helps someone to understand the history of a project, it conveys the house style for making images and it contains material for press use.


Encaustic tile for the Carrer Avinho apartment in Barcelona. “Encaustic tiles are a robust, beautiful, relatively inexpensive material. One idea that drove the development of the tiled floor was that the two brothers who own the property wanted to find a way of distinguishing whose part of the apartment they were in. The tile also references the triangular shape of the apartment. Made by Mosaics Martí who also made tiles for Gaudí, the tile is a standard item, but we were able to adjust the process to introduce a gradation of tone across the space. In its production a simple metal frame is used to create the pattern, and the craftsman is able to control which colour is put where”.

ExCinere tiles from Dzek for an extension to an apartment in Holborn. “We are always looking for suppliers who innovate in their materials. David met up with Dzek at a design fair in Milan, where they told him about these tiles they’ve developed with Formafantasma. They use a volcanic ash glaze. The exterior of the project is wrapped in the glazed tiles, which create a shifting, modulated tone across the building.”

Do you constantly monitor what is retained in the library?
I have a clear-out about every six months. The first criteria that I set for myself is, is it labelled? If it’s a beautiful piece of something but no-one knows where it’s come from, what possible benefit does it bring? Unless someone can identify it, it will have to go. Often a supplier will send you 15 variations of things and everyone in the office has a good eye so we know which ones we want to keep and will return the other samples where we can. We also have samples that are prepared by contractors that we are working with. We will write on the back the specification eg paint colour and how many coats were used, with what kind of brush even, and that gets kept as resource to discuss in the future.

How do you get samples in? Is that done individually or do you take responsibility for it?
A bit of both. It tends to be the project architect who does the selection of materials; it’s more efficient for them to order samples.


Marmoreal precast marble terrazzo tiles from Dzek, being used within a Berlin apartment building for Euroboden. Marmoreal is composed of some 95 per cent marble and five per cent polyester resin binders.

How much time do you devote to the materials library?
Probably just a few hours a month; it doesn’t ever feel chaotic. The point of having it here is that it’s a working resource. I tend to pick things up around the office and put them away if they haven’t made it into the right system but the office is pretty good at managing it themselves.

When the practice moved from Hampstead did it revise things significantly?
The very special things were kept; there would have been a filtering process: do we like this, is it relevant, would we ever use it again, is it still available? That’s especially relevant for textiles, linos, ironmongery. Also standards change; there are things you can no longer specify due to revised Building Regulations. We use a lot of brick and we hang on to brick samples, and stone samples from quarries that we like.


Design for screenprinted glass on two creative workspace buildings in the Design District on the Greenwich Peninsula. Jessica Lyons: “Bands of glass across the buildings create ambiguity of levels, and give some privacy to the workspaces. Part of the initial concept was to use glass block, but for various reasons we had to change to a standard pane of glass in a curtain walling system. A colleague drew up this design, which has a really nice hand-drawn quality, to emulate a glass block. It’s reduced in size and used in grids of nine for the banding.”

How do staff research materials?
David Kohn meets and talks with a lot of people and finds out about interesting materials that way. In the very early stages of a project, David might suggest something he’s come across and that may change its direction.

We also have regular CPDs, one every Monday lunchtime, on a material or a live project. They may be in line with the interests of a project or not. Accoya for instance came in and gave a very good presentation when we weren’t designing any timber buildings and it has informed what we might do. But we might feel we need to know, say, about kitchen design for a particular project, so we’ll get a specialist in to talk us through kitchen samples, how they can be worked and how that will inform the detail design.

We attend exhibitions and festivals in London, such as Craft Week. We also make quarry, studio and workshop visits; those in situ discussions with people who make or fabricate things can help clarify how we go proceed. We worked with Millimetre on the boat-shaped hotel room on the roof of the Queen Elizabeth Hall (A Room for London, designed in collaboration with artist Fiona Banner) and we’re doing so again currently. They have machines that we don’t have in our workshop so they’re preparing a lot of samples for us. That type of collaboration often pushes the design forward. We have ongoing conversations with manufacturers, suppliers and contractors about appropriate materials. We’re very open to having our minds changed.


Forticrete block. “Our use of blocks as an expression of the construction started with the White Building in Hackney Wick. We wanted to use a standard, inexpensive product, elevating the material through the particular setting out of the blocks. At the Ice Cream Factory in Devon we explored how we could use the material to create bays and special, enclosing spaces. The block we use tends to be whatever the contractor finds to be most economical then we will look at different samples. We treat it as almost as important as actual stone, achieving the right surface, with the setting out, the movement joint, the mortar. At Bere Knap, a house in Dorset, however, we’re using Forticrete blocks for a high-quality finish. They still prove to be more economic than plastering and painting: austerity chic! There will be a very light paint finish to blend the appearance of the block and the mortar.” MDF with a sycamore veneer for a piece of cabinetry at Hertfordshire House, Amersham.

Do you see the library as expanding?
As we take on new projects there are more things to get excited about, keep and treasure. It’s not a simple one in, one out policy. The studio interior changes quite regularly with our requirements. The scale of the New College Oxford project and the number of stakeholders involved means that we have lots of samples, so that has changed the way we look at storing things. We have regular meetings with the stakeholders where we use models and samples to excite them and bring the project alive. There’s definitely room to grow.