The Stone Demonstrator

John Hill | 29. October 2025

Photo: Bas Princen, courtesy of the Design Museum and Future Observatory

Future Observatory, the Design Museum’s national research program focused on transitioning to net zero and a green economy, has unveiled the Stone Demonstrator, a 1:1 scale pre-tensioned stone structure installed on the Earls Court development site in West London. The three-story installation was designed by Groupwork and engineered by Webb Yates and Arup.

A highlight of With Every Fiber | Pigment, Stone, Glass, an exhibition World-Architects recently saw at Grace Farms, was Stone Space Frame, a sculptural pylon by Webb Yates created using post-tensioned stone. The space-frame structure was made of stone struts post-tensioned with steel bars welded to each other to create nodes. The whole reportedly used 75% less carbon than a comparable all-steel structure and thereby proposed an alternative structural solution to steel and concrete framing: stone.

About a decade earlier, Webb Yates had worked with Groupwork, the firm of architect Amin Taha, on 15 Clerkenwell Close, a six-story building with a striking load-bearing stone facade. Although the unconventional design generated controversy when it was completed in 2017, the building was later shortlisted for the RIBA Stirling Prize. Although it didn't win, the shortlist brought attention to the building and the efforts of Groundwork and Webb Yates in exploring structural masonry, what Amin Taha describes as “the new Stone Age.”

The Stone Demonstrator sees Groundwork and Webb Yates collaborating once again, this time with Arup, on a public installation that serves as “a call for the construction industry to hasten its efforts to transition to low-carbon materials.” Photos of the Stone Demonstrator follow, accompanied by captions providing additional information on the installation.

The three-story structure measures 6.5m x 6.5m (21'4" x 21'4") and is open to the public on the ground floor. (Photo: Bas Princen, courtesy of the Design Museum and Future Observatory)

The Future Observatory contends that natural stone's low-carbon characteristics equate to a 70% reduction in carbon emissions over a concrete frame and 90% versus a steel frame. (Photo: Bas Princen, courtesy of the Design Museum and Future Observatory)

The Stone Demonstrator is made of stone blocks connected by steel tendons that were compressed to create pre-tensioned beams and columns. (Photo: Bas Princen, courtesy of the Design Museum and Future Observatory)

The beams and columns are prefabricated, modular elements that can be dismantled and reused after the run of the installation. (Photo: Bas Princen, courtesy of the Design Museum and Future Observatory)

The Stone Demonstrator's “purpose is not to promote stone for sentimental reasons,” Amin Taha said in a statement, “but as an ultra-low-carbon alternative to reinforced concrete and steel structures clad in fired clay bricks.” (Photo: Bas Princen, courtesy of the Design Museum and Future Observatory)

The sizing of the structural frame for the Stone Demonstrator could work in a building of up to ten stories, though with larger members it could be used in buildings from between 30 and 80 stories, depending on the jurisdiction and seismic characteristics. (Photo: Bas Princen, courtesy of the Design Museum and Future Observatory)

“The floor plates are a mix of pre-tensioned stone slabs,” per Future Observatory, “combined with timber joists and a roof of dowel-laminated timber (DLT).” (Photo: Bas Princen, courtesy of the Design Museum and Future Observatory)

“The structure has a self-supporting facade of stone bricks,” per Future Observatory, “which are at least 90% lower in carbon emissions than London’s vernacular of fired clay bricks.” (Photo: Bas Princen, courtesy of the Design Museum and Future Observatory)

The installation will be on site until construction starts next year on the 40-acre redevelopment of the former Earls Court Exhibition Centre site. (Photo: Bas Princen, courtesy of the Design Museum and Future Observatory)

Project: The Stone Demonstrator
Client: Future Observatory at the Design Museum
Site Partner: The Earls Court Development Company
Funder: The UKRI Arts and Humanities Research Council
Architect: Groupwork
Engineers: Webb Yates and Arup
Principal Contractor: Ernest Park
Stone Structure: The Stonemasonry Company
Hybrid Stone and Timber Floor Plate: Bamberger Natursteinwerk Hermann Graser
Dowel-laminated Timber Floor Plate: IQ Wood
Structural Stone Suppliers: Brachot, Carrière de Luget, Franken-Schotter, Lundhs, SigmaRoc
Stone Brick Facade: Hutton Stone and Albion Stone
Stone Installation: Ryker Structures
Facade Timber Supports: Rossmore Contracts
Stone Brick Garden Wall and Seating: Germans Balague with Bricklink and Brickability
Brick Layers: Bishop Facades
Landscaping: Lyndon Osborn & Team
Lighting: iGuzzini, Atrium and Pritchard Themis
Electrical Installation: Switch Technologies