The Stone Demonstrator is a low-carbon construction prototype, which puts pre-tensioned stone building techniques to the test.

The Stone Demonstrator is a boundary-pushing stone prototype, located on the Earls Court Development site, calling for more sustainable materials and building practices in the construction industry. The open-air Stone Demonstrator stands at three storeys tall, measuring 6.5m x 6.5m, with the ground floor and adjoining park open to the public.

It has been designed by architecture practice Groupwork with engineers Webb Yates and Arup. The Stone Demonstrator, funded by Future Observatory and the UKRI Arts and Humanities Research Council (AHRC), acts as both a 1:1 scale research tool and a call for the construction industry to hasten its efforts to transition to low-carbon materials.

Nearly 40% of global carbon emissions are created by the built environment, with 11% coming from the construction of new buildings. Natural stone is an extremely low-carbon material. The Stone Demonstrator is a prototype of an alternative way to build that reduces carbon emissions by approximately 70% compared to a reinforced concrete frame, and 90% compared to a steel frame.

The Stone Demonstrator consists of stone blocks that are connected by steel tendons and compressed to create pre-tensioned beams and columns. The floorplates are a mix of pre-tensioned stone slabs, combined with timber joists and a roof of dowel-laminated timber (DLT). The structure has a self-supporting facade of stone bricks, which are at least 90% lower in carbon emissions than London’s vernacular of fired clay bricks.

Alongside the Stone Demonstrator prototype, Future Observatory has also funded engineers at University College London to develop a guide to designing stone structures. The design guide, led by Professor Wendel Sebastian at UCL, offers an invaluable tool for the construction industry to make stone structures easier to adopt, and is a key step towards a building code for stone.