Architect Alastair Mitchell and textile designer Kezia Regan describe their journey to discover cast concrete and the founding of their Peckham-based design studio, Conpot.
HI/ What triggered to you to start designing and creating products with cast concrete?
AM/ When I first started experimenting with concrete I was studying architecture and we were going on trips to pre-cast concrete factories. I started borrowing ideas on how you can use more beautiful stone in concrete as opposed to just sand, cement and water. I designed a geometric rock form which I then had 3-D printed and used as a cast. When I explored cast concrete further I went into the ceramics workshop at uni where they taught me mould making. The first Conpot product was a faceted plant pot made using a hot rubber mould – everything grew from there.
HI/ There’s an architectural quality to Conpot plant pots. Do you think your pots are architectural because you’re an architect or did you make them in a style that is architectural?
AM/ I was definitely inspired by Brutalist architecture but as I started working with concrete I changed the way I was working. During my studies I did a trip to visit Le Corbusier’s buildings in France and got to see how he experimented with concrete. Fondation Suisse at the Cité Internationale Universitaire, Paris has these very expressive staircases; Sainte Marie de La Tourette in Lyon is based on a monastery and the concrete had been hosed onto the walls. After seeing that I was a bit obsessed. I realised concrete isn’t just this Brutalist material – it’s so malleable you can do just about anything with it.
KR/ Le Corbusier’s buildings are all set in nature so it was also an inspiring idea that concrete sat with nature.
AM/ The style of Conpot pots has evolved quite alot. The original faceted prototypes were cast in a mould. I would then I polish them down until I reached this ideal form. Whereas now it’s not so much about the shape but rather the material and the form that concrete gives it.
KR/ Yes, the round concrete pots we have developed out of trial and error. We kept developing them until the proportions made sense to us.
HI/ How are Conpot products made and what materials do you use?
KR/ Provenance is important to us: we like to know the story behind the materials. We use white marble from Spain, black basalt from Shropshire, grey limestone from Darbyshire, red granite from Scotland and flint, which at first is a dull colour but when baked in a kiln transforms into pastel tones. We use Portland cement, which is the highest quality and frost proof. The proportions of the mould are very important because that controls how the cement mixture sits in the mould. It also determines how it sets. You don’t know until you polish it how the aggregate has settled. We’re purposefully not scientific about the mix of aggregates because we want every batch to be unique so that we never make the same pot.
I really enjoy the physical work involved in making concrete plant pots and also the process. I’m a textile designer, which involves very specific processes that you need to get right for the final product to work. In Conpot planters we use three sizes of stone to create the concrete mix: the cement, a ground stone, and aggregate. We mix these with water and pour them into our moulds, lock them in place and then vibrate the mixture to get rid of most of the air bubbles.
AM/ The cement reacts with the water to create stone, and gets harder and harder as the moisture escapes. After two days, we polish the concrete using four different grains of polishing pads to reveal the aggregate and then we seal them. All together it takes four whole days to make a pot.
HI/ You have a charming collection of potted plants in your own home. Where did your desire to have plants in the home come from?
AM/ Having plants in the house has always been normal for me. I grew up on the Isle of Wight. My grandfather, who is an architect, has a very unusual house which he built for his family in the 1960s. It’s a mid-century bungalow that steps down a hill and is surrounded by garden. In the living room is a rubber tree growing out of the floor. The ceiling width is over 10m long and is covered in rubber leaves. Originally it was a conservatory and my grandfather extended the living room out around it; rather than get rid of this mature tree, he kept it in the floor.
KR/ When you’re renting, it’s nice to know you can build a collection of plants and take them wherever you go, whereas a garden gets left behind. For us the pot isn’t just a vessel, it’s an object in itself, so indoor plants can also become a form of decoration.
AM/ I think it used to be more normal to have house plants. With minimalism in the 1980s and 90s, people did away with plants. Now everyone is living in a clean white space with everything hidden and plants are creeping their way back in.