French studio Niveau Zéro Atelier has salvaged waste clay from construction sites around Paris and vacuum-sealed it to form the padding of a chaise lounge that was unveiled at the Collectible design fair in Brussels.

In the absence of air, the clay remains wet inside its clear plastic sheath, allowing the Soft Soil daybed to mould to the body of its occupant as if it were made of Play-Doh.

Set on a spartan base of recycled stainless steel, the only colour is provided by the clay itself, which has a naturally pale green hue before firing.

"It's such an interesting way to look at upholstery," said Richard Healy, creative director of London-based design platform Relay Design Projects, which commissioned the piece.

"It's an unexpected material to bring into that conversation," he added. "For us, that was most intriguing: how it questions so many status quos in terms of upholstery."

Niveau Zéro Atelier sourced the clay from construction sites in the suburbs of Paris, where it piles up as a waste byproduct of the excavation process.

The greyish-green colour of the illite clay comes from its mineral-rich composition, which makes it a popular ingredient in face masks and other beauty products.

To make the clay useable, it had to undergo a rinse-and-repeat refining process that involved the clay being mixed with water so it could be filtered through a cloth before being left to rest and separate from the water, which was subsequently poured away.

These steps were repeated until all impurities were removed and the clay could be piped into the clear plastic envelope.

"Refining the clay and placing it into these encapsulated forms is very labour intensive," Healy told Dezeen.

Using four separate valves and a vacuum sealer, the studio sucked the air out of this plastic pillow to ensure the clay stays wet and malleable.

The bright red lids used to seal the envelope can be slotted into matching holes cut out of the daybed's reclinable backrest to hold the padding in place.

Button details on the front reference traditional Chesterfield upholstery and contrast with the pared-back industrial feel of the metal base.

Niveau Zéro Atelier first started working with reclaimed clay as part of its MEGA project, in which the studio set up in-situ ceramic production facilities on construction sites around Paris.

Using this clay, the collective made smaller pillows and seat cushions using the same process as the Soft Soil daybed, alongside a range of vases with a warm terracotta hue that surfaces as the clay dries in the firing process.

"As well as using the clay in its wet form, they also fire it into ceramics," Healy said. "So there's a really nice way in which they look at the fulness of the clay and its whole cycle from wet to fired."

Based on these experiments, Relay Design Projects commissioned Niveau Zéro Atelier to push its technique for encapsulating clay to create a more large-scale piece – the Soft Soil daybed.

An offshoot of London design agency Relay Design Agents, the platform pushes designers to produce work outside their regular remit by experimenting with new materials, formats or processes.

"We try to provide artists and designers with the space and resources – whether that be finance or connections to industry – to help them produce work that they've always wanted to produce," Healy said.

At the Collectible fair, Soft Soil is on display alongside the latest cohort of Relay Design Projects including ones by London studio EBBA Architects and Swedish firm Haha Studio.

The design fair itself, now in its seventh year, just announced its expansion onto US soil with the launch of its New York edition this September.

Collectible 2024 takes place from 7 to 10 March 2024 at the Vanderborght Building in Brussels. See Dezeen Events Guide for an up-to-date list of architecture and design events taking place around the world.