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TAGASIWhen a certain building technology or material is sidelined for an extended period, one is bound to get the impression that it is intrinsically obsolete. This has happened with natural stone, which architects, when asked about its potential for use, describe only as being too expensive, too labour-intensive, incompatible with the public procurement system and, as can be witnessed in renovation projects, simply too complicated to build with. The inability to imagine a future different from the present is typical to the 21st century, and hence, the main use of limestone in Estonia remains blasting it into rubble that can be utilised as landfill and concrete aggregate.
There are some who think differently. ‘Stone is a new material in our technological context,’ argues English structural engineer Steve Webb in his polemical essay ‘Stone age: a new architecture from an old material’, published in the Architectural Review in 2022. Since the 19th century, research and development in the field of concrete and steel, as well as the curricula of engineers and architects, have completely banished stone from construction, and created a biased conception of building materials.1 In the age of fossil fuels, the euphoric triumph of the aforementioned new materials was a logical outcome—cheap, seemingly endless energy enabled, and still enables, to replace time-consuming masonry work and the expertise involved with a simpler and faster concrete and steel construction. Paradoxically, now that visible catastrophic consequences let us perceive such volumes of energy use as exploitation of our planet, energy has instead become a reason for rediscovering stone.
There is one obvious, Excel-compatible reason why use of stone is back on the agenda—as a building material, stone is low in embodied carbon. Given the direction towards stricter CO2 regulations in the construction industry, we can hope that instead of virgin materials with high levels of embodied carbon, we will turn to readily available, renewable and reusable materials that do not require much processing. The amount of embodied carbon in a stone product that is ready for use in construction is about the same as in CLT (in CLT, it is 219 kgCO2e/m3 ; in stone, 237 kgCO2e/m3; in reinforced concrete, 635 kgCO2e/m3 and in steel, 12 090 kgCO2e/m3).2 After it has been quarried, stone does not require much processing, although how much it needs depends on transportation distances, designer’s knowledge as well as aesthetic choices, not to mention the craftsmanship of the builder. Stone has a longer life span than CLT, and is needed in smaller quantities as it is stronger. This does not mean that one should replace the other—they can be used together efficiently and this is indeed what we should do.
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Full article: https://ajakirimaja.ee/nurgakivist-tootasapinnaks-ja-tagasi/
1 Steve Webb, ‘Stone age: a new architecture from an old material’, The Architectural Review, 6 April 2022.
2 Cíaran Malik, ‘Cradle to Gate Embodied Carbon A1 – A3’, a diagram from the author’s website, which is in turn based on the database ‘Embodied Carbon – The ICE Database’ (2019), circularecology.com.
