Stone Skyscrapers: A Cheaper, Greener Future for Tall Buildings?
Architecture studio Groupwork, in collaboration with structural engineer Webb Yates, has unveiled a conceptual design for a 30-story skyscraper constructed with a stone exoskeleton. This innovative project challenges conventional building materials like steel and concrete, proposing stone as a more cost-effective and environmentally sustainable alternative for large-scale commercial developments.
Key Takeaways
- A 30-story stone skyscraper concept has been designed by Groupwork and Webb Yates.
- Research suggests stone structures can be cheaper and significantly reduce embodied CO2 compared to concrete or steel.
- The design utilizes an exoskeletal, post-and-lintel system, extrapolating from previous smaller-scale stone projects.
- Basalt was identified as the best-performing stone for structural integrity and fire resistance in tall buildings.
- Combining stone with cross-laminated timber (CLT) floors could lead to carbon-negative buildings.
Rethinking Stone in Modern Architecture
Amin Taha, founder of Groupwork, stated that the project aims to demonstrate the viability of stone for tall buildings, highlighting its potential to reduce embodied CO2 by up to 90%. "It's research to investigate how tall you can go in stone," Taha explained. "[To] demonstrate to commercial clients – that are consistently building a lot and at a large scale – that it's cheaper and enables a 90 per cent reduction of embodied CO2."
The concept draws inspiration from Groupwork's previous RIBA Award-winning project, 15 Clerkenwell Close, adapting its exoskeletal, trabeated (post-and-lintel) structure to a much larger scale. The 30-story design utilizes basalt, which performed best among tested materials like limestone and granite for structural integrity and fire resistance requirements of up to 120 minutes.
Environmental and Economic Advantages
Sustainability consultants Eight Associates calculated that using stone quarried domestically could lead to a 95% reduction in embodied CO2. Compared to steel frames, the reduction could be around 60%, and approximately 80% compared to concrete structures. The report emphasizes that stone itself has a zero carbon footprint, with emissions primarily stemming from quarrying and transportation.
Furthermore, combining the stone exoskeleton with cross-laminated timber (CLT) floor slabs could result in carbon-negative buildings, as timber sequesters CO2. "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," Taha noted.
Cost consultants Jackson Coles indicated that while the initial cost of a stone structure might be slightly higher, the overall expense would be lower due to the elimination of the need for fireproofing, weatherproofing, and stone veneer cladding. This research is part of the "New Stone Age" exhibition at the Building Centre in London, aiming to showcase stone's potential as a modern, versatile, and sustainable building material.
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