Groupwork Architects Investigate the Sustainable Advantage of Structural Stone

Written by Christele Harrouk
Published on March 12, 2020

Groupwork, in collaboration with Jackson Coles, Eight Associates, Webb Yates, The Stonemasonry Company and Polycor, is investigating the possibilities to build large commercial buildings in stone, through the Stone Tower Research project and The New Stone Age exhibition.

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Researching how far one can go using stone, Groupwork has imagined a 30-story basalt structure with a total Gross Internal Floor Area of 37,800 m² / 406,875 ft², part of the Stone Tower Research project. The comparative study considering many structural solutions aims to “investigate whether large scale commercial buildings can be built with stone superstructures, stone and or timber floor plates to meet the same criteria of optimum office space and building height as steel and concrete structures and be the same or lower in construction cost and carbon footprint”.

Groupwork 15Clerkenwell. Image © Tim Soar

Exploring exoskeleton structure, central cores, type of stone, fire performance, and environmental performance, the findings confirmed that “a combination of stone exoskeleton with CLT floor slabs is cheaper than the equivalent building using steel or concrete frames and with a negative carbon footprint”. In fact, the envisioned architecture aims to highlight that building with stone, with large floor plates in either CLT or pre-tensioned stone, can be cheaper with a 90% reduction of embodied CO2. Finally, the discovery is underlining what the architects knew all along, for 7,000yrs: Stone is versatile, strong, abundant, cheap, has longevity, and with zero embodied carbon.

At the Building Centre, a landmark exhibition entitled The New Stone Age, “will explore the potential of stone to revolutionize architecture and construction in light of the current climate crisis”. Curated by Amin Taha of Groupwork, Steve Webb of Webb Yates and Pierre Bidaud from the Stone Masonry Company, the exposition will highlight the sustainability, practicality, beauty and contemporary use of structural stone. Moreover, the exhibition will feature the works of international designers, including French practices Studio Lada and Carl Fredrik Svenstedt, the Palestinian-based AAU, Ensamble from Spain, as well as Hopkins Architects, Eric Parry Architects, Groupwork, Webb Yates and Arup.

Stone is beautiful, strong and abundant. Its extraction doesn’t require huge amounts of energy. Modern improvements in design and analysis techniques mean that it can be used in ways not thought possible before; playing a major role in building structures. - Steve Webb

Part of The New Stone Age, the installation on the South Crescent, Store Street, presents the impressive sustainable credentials of structural stone, whilst providing shelter and seating area for the public. A prototype of a structural stone floor, the project showcases that structural stone flooring can have a carbon footprint of only 15 percent of its hollow core concrete, with steel reinforcing, equivalent and at the same cost.

The New Stone Age marks a return to the use of stone and wood; low-cost materials with an embodied carbon of zero and negative respectively. Materials once thought of as anachronistic, no progressive, and non-modern. Stone as combined superstructure and external architectural finish allows us an opportunity, by limiting the input of energy in processing, transportation and construction to drop the world’s CO2 emissions - of which the building industry contributes 33%, - by anything between 60% and 90% for these key building elements. This is far in excess of our current thought of as ambitious targets and yet simply achieved by once more including stone as part of the family of structural-architectural materials. - Amin Taha