A new exhibition reflects a rebirth of interest in stone as a sustainable, beautiful and inexpensive structural material, say curators Amin Taha, Steve Webb and Pierre Bidaud

‘The New Stone Age’
Curated by Amin Taha (Groupwork Architects), Steve Webb (Webb Yates Engineers) and Pierre Bidaud (The Stonemasonry Company)
The Building Centre, London, until 15 May 2020.

In the light of the climate crisis, our building materials need more than ever to prove their worth. Stone has significant sustainability credentials, with the ability to dramatically reduce a project’s embodied carbon. This, as well as the practicality and inherent beauty of natural stone, is among the characteristics celebrated in ‘The New Stone Age’, a current exhibition at the Building Centre that we – an an architect, an engineer and a stonemason – have curated.

Another benefit of working with stone is the interdisciplinary collaborations it fosters – indeed the three curators collaborated on the 15 Clerkenwell Close (AT284), an exemplar of structural stone – but the increased divergence of specialist disciplines over recent years is perhaps to blame for the lack of integrated understanding of the material.

Top: Four apartment blocks at Plan-les-Ouates, Switzerland, by Perraudin Architecture. The practice frequently uses structural stone insulated internally with cork, and founder Gilles Perraudin is a champion of the mid-century work of Fernand Pouillon.
Above: Structural stone projects undertaken by Amin Taha’s practice, Groupwork Architects, with engineer Webb Yates: CGI and prototype of red Sicilian basalt stonework for a 10-storey development on London’s Finchley Road; entrance and loadbearing stone frame at 15 Clerkenwell Close; and ‘Sheltering Under Marble Skies’, an installation at the Venice Biennale trialling a canopy of green resin bonded waste stone.

In our various collaborations and research work, we have identified benefits to stone that many find surprising. Applying contemporary software tools and materials to construction in stone was a revelation to the industry’s cost consultants and contractors, who typically associated stone with expense: a building’s superstructure can be erected in stone at a cost potentially 25 to 75 per cent lower than steel or concrete frames (thanks to the complexity of cladding systems being replaced by using a loadbearing frame) and save 60 to 90 per cent of their embodied carbon.

We do not expect stone to supplant steel and concrete, but the projects featured in the exhibition do suggest a ‘rediscovery’ of the material which will help define it as an authentic aesthetic for our age, whether for sustainability, cost or broader cultural reasons.

Above: The fifteenth-century Stairs of Reconciliation, Graz, Austria; Joseph Abeille’s 1699 patent for a flat vault using ashlars in a polyhedron form

Many of the projects make use of and evolve techniques that have only recently been forgotten. Over the past 7,000 years we have continued to apply our ingenuity to this material with only a recent 100-year break. Greek masons refined entasis and perspective correction in their stone abstractions of timber temples, and the development of stonemasons’ knowledge reached an apotheosis in the late-eighteenth and early nineteenth centuries with stereotomy – cutting one solid to interlock with a partnering solid, transferring load through each block to the ground. This is perhaps best illustrated in the patents French engineer Joseph Abeille for reciprocal flat stone vaults and the staircases and floor plates at the monastery of Notre Dame de la Couture, Le Mans.

These advances in the use of structural stone were reflected in many daring staircases of the period, not least the double spiral staircase of the Burg in Graz. This part-cantilevered, part-reciprocal stair achieves its twisting ascent through the building without any tensioning of the stone and derives its nickname – the Stairs of Reconciliation – from the way the flights diverge and recombine between each landing.

Stone has been and continues to be used for structural purposes without dictating any architectural style, but the industrial age saw it increasingly replaced with steel and concrete, and in the post-war period it was conflated with the past, seen as anachronistic and even anti-progressive.

Above: La Tourette housing, Marseille (1955), designed by Fernand Pouillon.

This was in spite of the efforts of Fernand Pouillon. His work in France in the post-war years demonstrated that multi-storey housing was faster and cheaper in stone than concrete or steel, but was largely ignored in favour of new materials emblematic of modernity. Most notably, Pouillon built housing and shops on Marseilles’ waterfront for a fifth of the cost of Corb’s nearby Unité d’Habitation. Going on to win tenders across France, he and his troupe of stonemasons stood somewhat adrift from the drive for novelty. And with his imprisonment under a law against acting as both architect and contractor, the period of stone as a widespread and combined structural-aesthetic building material seemed to come to an end.

Above: Delas Frères Winery, France (2019), designed by Carl Fredrik Svenstedt. The 70-metre-long wall of the wine store is made from local Estaillade stone extracted from the Rhône river. It is composed of 500mm-thick CNC-cut blocks laid using traditional techniques (phs: Dan Glasser).

Pouillon’s influence is present in some of the buildings and structures featured within the exhibition, all of which are all loadbearing, external of the thermal envelope. Others continue in the tradition of stereotomy, using today’s software to parametrically reform Abeille’s reciprocal vaults and enabling the extraction and cutting of stone at lower cost.

Stone has been used for millennia to create robust shelters and memorials to those passed, and to express cultural ambitions for longevity. To a large degree, we are relearning what ‘we’ have always known. In that sense, the exhibition should perhaps have been called ‘The Stone Renaissance’.

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