“It’s like nose-to-tail eating, but for trees,” says Paloma Gormley, co-founder of the ecological design studio Material Cultures. “Industrial timber production is so wasteful. We should be making the most of every element of the tree, from its bark to the natural glue-like lignins and rosins – it all has value.”
The organisation’s philosophy is currently on display at London’s V&A in a show called Material Cultures: Woodland Goods. A hairy brown wall hangs in the museum’s furniture gallery, alongside some unusual plywood stools whose seats have been exchanged for slabs of compressed bark. Nearby are sheet materials made from pine needles and sap, papery silver birch bark encrusted with dried moss, and other experiments with things gathered from the forest. It’s quite a contrast to the polished furniture on display in the museum’s permanent collection, as if there’d been a rustic takeover by a crafty team of beavers and squirrels.
Gormley, who is the daughter of sculptor Antony, founded Material Cultures with Summer Islam and George Massoud in 2019. While most architects are used to selecting proprietary products from catalogues, often without knowing much about their origin or impact – pairing aluminium composite cladding panels with petrochemical insulation systems – this trio prefer to go back to the land and harvest their materials from the natural environment.
“Birch bark is like the original dampproof membrane,” says Massoud, as he rifles through a pile of woody material tests in the firm’s east London studio. Their samples library looks more like the contents of a lumberjack’s cabin than an architect’s office. “Bark has been used by indigenous groups for hundreds if not thousands of years, from roofing to canoes, harvested in ways that don’t damage the trees.” While the timber industry treats bark as a low-value waste product, generally shredding it into chippings or mulch, Material Cultures has been exploring how its natural properties could have useful applications in architecture.
Working with fabricator Erthly, the designers have tested layering and heating bark under pressure to create plywood-like sheets, bound with the trees’ natural resins instead of the usual chemical glues. Some of the results, such as a panel made from six layers of birch bark, have a dense, plasticky quality that could make for good exterior cladding. Others, like a thick sheet made from three layers of hairy redwood bark, are more voluminous and fluffy, lending it well to insulation, with natural fire-retardant properties to boot. “The same qualities that protect trees from rain and forest fires,” says Gormley, “could also protect buildings.”
In the eyes of Material Cultures, the intrinsic link between architecture and agriculture must be reinstated if we are to reduce the carbon footprint of the built environment, which currently accounts for more than 40% of CO2 emissions in the UK. If supply chains are more transparent and local, they argue, then we will make more responsible choices. “There’s a culture of negligence built into our industrialised system,” says Gormley. “Buildings have become so detached from their consequences, that it’s easy to behave irresponsibly.” We must understand buildings as being “irrevocably linked to landscapes of extraction”, the designers argue, and work towards a bio-regional approach that prioritises plant-based materials and regenerative practices. It’s the architectural equivalent of shop local.
The radical trio set out their stall in a powerful call-to-arms manifesto, Material Reform, co-authored with Amica Dall in 2022. Now, the first permanent built fruits of their approach are being realised. On a three-acre former council parks depot and nursery in Wood Green, north London, stand three barn-like sheds. One houses a community hall, another contains classrooms and offices, while the third will be home to a workshop and food packing facility. Designed in collaboration with Studio Gil, they are built with lightweight timber frames, infilled with bales of straw grown on the edge of London, and rendered with clay dug from the site itself and mixed with sand and chalk, protected by thin timber laths. Floors of limecrete are cast on top of insulation made of foamed glass recycled from car windscreens, while internal walls are built of “strocks” – chunky blocks of unfired clay-rich earth mixed with chopped straw, developed by brick company HG Matthews.
“Strocks save vast amounts of carbon because there’s no firing involved,” says Gormley. “They’re also good acoustically, provide great thermal mass, and they’re antimicrobial and hydroscopic, so they regulate the indoor temperature and humidity.” While other synthetic interior materials can give off harmful VOC gases, like formaldehyde, the clay blocks actively sequester them. Budgetary constraints necessitated a corrugated steel roof, rather than a bio-based alternative, but at least it’s recyclable.
The £2.8m project, funded by the Mayor of London and National Lottery, provides a new community food growing hub run by local grassroots organisations the Ubele Initiative and Organic Lea, who helped to build it in a collaborative effort.
“We had our members involved in everything from making the straw bales to bricklaying and clay plastering,” says Yvonne Field, the founder of Ubele, a social enterprise dedicated to supporting black and minority-led community spaces. “It was great for building community cohesion, and giving people practical skills they can now go on to use elsewhere. It saved a significant amount of money too” – a boon when construction inflation saw costs almost double.
The three barns stand alongside the council’s 1970s glasshouses, including a palm house complete with a koi pond and resident terrapins. One greenhouse is now used by Black Rootz, a local growers’ collective, another to grow herbs for Yotam Ottolenghi’s Rovi restaurant, while a third is dedicated to cactuses. “We host Nopalera Sessions music nights,” says Mexican artist and chef Elki Guillen, as he lovingly tends to his collection of prickly pears. “The music is mainly for the benefit of the plants, but sometimes we invite humans too.” Guillen has also been experimenting with cactuses as a building material, mixing their fibres and mucilage into adobe and lime render as a binder and water repellent – a vernacular technique used in Mexico since Aztec times, which he thinks could have applications here too.
A few streets away, Black Rootz and Organic Lea run another community growing site, the seven-acre Pasteur Gardens, where Material Cultures has also been busy. Alongside beds planted with tall canes of sorghum, which can be pressed to make syrup, and callaloo, a plant used in Caribbean dishes, stands a handsome little pitch-roofed cabin. Built during participatory workshops last summer, the designers see it as a “demonstrator” project for ultra low-carbon homes.
It features walls made of “light earth” – a loose mix of straw and clay packed into the timber frame, which is more insulating than rammed earth or adobe blocks; similar to hempcrete but without the embodied carbon of lime. The exterior has been wrapped with a shaggy coat of thatch, “like a giant duvet”, says Massoud, with offcuts left strewn on the ground where they will decompose – another benefit of using natural materials. Contrary to the build local philosophy, the reeds came from Romania, but Gormley is optimistic about more local supply chains in future, “when the rewetting of the fens happens”. The cabin serves as a shelter and seed library, but the practice has designed it to comply with domestic building regulations, and they intend to publish the plans and specifications, allowing other people to build one themselves. “It’s a module that can be extended and multiplied,” says Gormley, and it can be built – a bit like Walter Segal’s 1970s timber-framed houses – with “zero to minimal skills”.
Training more people in natural building methods is one of the practice’s key priorities. Alongside its design and research (which includes a material strategy for Birmingham and the West Midlands, and a circular bio-based construction plan for Yorkshire and the north-east), it is ramping up its educational ambitions with plans for a school. On a 500-acre former farm near Broxbourne in Essex, just north of the M25, the rewilding organisation Nattergal has been working to take the land back to its former state as woodland pasture, funded by biodiversity net gain payments from housing developments nearby. Material Cultures hopes to convert a group of huge barns here into a “land lab” for plant-based building.
“It would be a permanent, dedicated place where we could both experiment and share knowledge,” says Gormley. “We’re trying to bring agricultural and building practices closer together, so you could come and do a course in regenerative farming, but also do some modules in straw bale construction.”
Beyond training, the trio argue, deeper structural reform is needed to ween us off the current “oil vernacular”. From buildings insurance to mortgages, materials testing and regulatory standards, everything is influenced by the all-powerful petrochemical and cement lobby. “The building industry is inherently designed to favour business as usual,” says Massoud. “Natural materials are all about repair, whereas with oil-derived materials, you’re buying into a system. If the system fails, then you have to replace the whole system.” As the Grenfell inquiry so excoriatingly revealed, the current system has failed us – it is long past time to replace it.