July 1, 2025
Thatch—The Past and Future of Green Building?
Thatched reeds have been part of building vernaculars around the world for centuries and the Aymara and Uru communities in Bolivia and Peru still craft boats and floating villages from the material, which has a high silica content, making it naturally water and fire resistant. But the industrial revolution saw reed and straw—a less durable but once prevalent thatching material—replaced by slate and cheap manufactured alternatives in many parts of the world, putting thatchers out of business.
Meanwhile, the drainage of wetlands for agriculture has decimated the rich ecosystems in which reeds are grown, forcing many of the remaining thatchers in Europe, for example, to import reeds from China. Half of wetlands in Europe and continental US have been destroyed in the last 300 years, according to a scientific paper published on Nature.com in 2023, and 75 percent in the UK—a region where the chocolate-box thatched cottage is part of cultural identity. But their preservation is crucial: globally, peatlands store twice as much carbon as forests.
Architects are reawakening to the merits of renewable reeds and finding new ways to express them, suggesting that wetland restoration and responsible farming for construction could go hand-in-hand. Rotterdam-based Arjen Reas Architects has wrapped the roofs and walls of several homes in the material, describing it as like a “warm coat” that links rural buildings to their surroundings. “When you lie in bed and gaze out of the window, you can see the material, which connects you to the environment,” says Reas. Thatching typically costs more than conventional roofing materials, he adds, but it saves money on energy bills by keeping a house at a consistent temperature.
Over on the shores of Hungary’s Lake Balaton, where reeds grow in abundance, RAPA has enveloped a house’s roof, walls and the underside of cantilevered living spaces in reeds—harvested by the thatcher himself—which soften the acoustics on the terrace beneath. The home has since become Instagram-famous, helping to boost the appeal of the material, but co-founder Ádám Reisz says that he still battles with people’s preconceptions. “They don’t see it as reliable,” he says. But a thatched roof can last up to 40 years if properly maintained. Reisz advises a “quick preen” every couple of years to maximize longevity, involving removing moss, pushing back errant reeds and replacing bits where the density has been lost. Meanwhile, Reas sees the beauty in the material’s patina of age. “It reacts with time and weather conditions, but I see this as something positive,” he says.
Despite reeds’ silica content, thatching is often deemed a fire risk by insurers as it is more combustible than slate, for example, but Reas mitigates this by fixing the thatching to a multiplex board directly on a layer of insulation, eliminating any air pocket—and keeping premiums down. In Denmark, the Royal Danish Academy’s CINARK is currently experimenting with spraying straw thatch with inflammable clay.
Although thatching repels water, architects often add impermeable layers of petro-chemical-based materials to prevent ingress. But when Dutch studio LMNL Office for Architecture and Landscape built Veldhuis amid the farmlands of North Brabant, it was adamant that the house could “breathe”—like those in past centuries. “Why would anyone live in a hermetically sealed plastic bag?” co-founder Robert van der Pol asks, pointing to how typical roofing products are high in embodied carbon and unhealthy for those that build a house and live in it. “The idea that materials can be grown, used and then composted and returned to nature is, in our opinion, common sense.”
Veldhuis has a cross laminated timber frame, and a biobased, vapor-permeable buildup of a Solitex Adhero membrane, wood fiber insulation, Elka ESB board, and local thatch. Reeds cover the roof and some of the walls, helping it meld with the landscape.
Such houses rely on the knowledge of master thatchers, passed down the generations. But in areas where that knowledge has faded—or never existed—could there be simpler ways to use reeds and straw? That was the thinking behind the prototype building that UK-based design and research organization Material Cultures conceived for a food growing site in London, made in collaboration with growers and builders during workshops. The straw and clay walls of the Pasteur Gardens building are clad in small, vertical bundles of reed, which are quick to make and replace, and are protected by a corrugated metal roof with large eaves.
“The idea was about knowledge transfer,” says co-director George Massoud of the structure. A thatcher and a straw specialist helped shape the construction system and pass on their know-how, but the prototype can be replicated by less skilled hands elsewhere. “The process of design and making became a tool for reimagining a reparative relationship with the land,” Massoud adds.
Materials Cultures is leading the charge towards bio-regional construction that goes hand-in-hand with regenerative agriculture. In 2023, it spent weeks wading through bogs in the German state of Brandenburg to explore how responsible wetland farming can provide renewable construction materials while rehabilitating the peatlands. Their wetland roamings have inspired their exhibition design for Thirst: In Search of Fresh Water, opening at London’s Wellcome Collection on 26 June (until 1 Feb 2026). Visitors will pass through a door in a thatched wall to enter and display boards will be made from pulped and heat-pressed wetland materials such as reed and sedge from the Norfolk Broads—Britain’s largest protected wetland—to discover a show exploring the importance of fresh water for both living beings and landmasses. It feels pertinent in a country with a dire history of nurturing its marshes.
Could we help rebuild the world’s carbon sinks as we construct our homes? It’s an idea worth floating.
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