Blog Author: Richard Saxon, CBE
The Extinction Rebellion movement has certainly rekindled the awareness of everyone that climate change is real, and that drastic action is essential. But what can we in the built environment do differently other than the slow, incremental changes that are in train? Recent books point the way and give rise to some optimism.
There are two, related areas of change to consider. Firstly, energy use in both making and running buildings must become zero-carbon. Secondly, the linear approach to building materials: mine, process, use, dump, must become a circular approach, cutting the destruction of natural resources and habitats.
On zero-carbon energy, Chris Goodall’s books, ‘The Switch’ [1] and ‘What We Need To Do Now’ [2], paint a picture where photo-voltaic (PV) power collection and wind power are poised to become dominant. Both are increasing rapidly in capacity and falling rapidly in cost, eventually undercutting all other options. For the sunny majority of the globe, solar can become a complete answer, also saving the need for expensive national grids. The great drawback of PV, that it only delivers in daylight, is also being overcome by the rapid fall in cost of big batteries. For the northern countries where PV can’t deliver in winter, wind usually can. The chemical routes to using PV and wind power to create hydrogen and hydrocarbon fuels, incidentally capturing carbon dioxide from processes and the atmosphere, are on the way to being competitive with fossil sources. Aviation fuel, the hardest nut to crack, can be synthesized. Buildings will be partly surfaced in PV collectors, which will be competitive with conventional roofing and cladding materials. Batteries will be a normal part of plant rooms. High performance buildings, with demand for power digitally managed to smooth out peaks, will enable the transition.
As to materials, our guide is the excellent ‘Building Revolutions’ by David Cheshire[3]. He restates the logic of the Circular Economy first laid out by Braungart and McDonough in ‘Cradle to Cradle’[4], that eventually all materials should be in continuous circulation, with little more mining needed. Organic and inorganic materials would never be mixed, to assist recovery, as once mixed they are inseparable waste. New buildings and refurbishments would follow circular principles. The lifecycle of any building is really a multi-layered one, with six ‘S’ layers, like Russian dolls, each having a lifespan. Sites endure for centuries as city plans rarely change. Structures can survive 60 years. Skins (envelopes) vary between 25 and 60 years, with glazing at the lower end. Services are obsolete or worn out in 15 to 25 years. Scenery (the interior fitout) lasts as long as the occupier’s needs, but rarely more than 15 years. Stuff (the furniture, fittings and equipment) moves around continuously and wears out fast. ‘How Buildings Learn’ by Stewart Brand, is always worth revisiting on this subject[5].
Cheshire suggests that designers should separate these layers, making it simple to replace worn out elements without burying shorter-life parts inside longer life ones. Owners should consider leasing shorter-life elements rather than buying them. Leased services and fitout systems are appearing on the market, enabling the suppliers to offer ‘performance as a service’ and to recover materials for re-manufacture when parts are replaced. Structures should be designed for longer life, change of use and/or eventual disassembly into reusable parts. The current ‘Sector Deal’ development work on ‘Platform-based’ offsite construction envisages a kit of parts for schools which can be recovered and reused in due course.
The embodied carbon in materials and manufacture can be reduced by the growth of renewable power as the main source of energy. Embodied carbon is becoming the dominant factor as operational carbon emissions are tamed. Material ‘passports’ to show the provenance of everything is suggested, aligning with Dame Judith Hackitt’s call for a Golden Thread of data about what a building is made of, for safety reasons. We already have a European standard for Environmental Product Declarations which form these passports. Recycling depends on certainty of material content and buildings can be valuable banks of materials.
Buckminster Fuller, in the 1960’s, envisioned a world where existing materials circulated, with each reuse more efficient than the last. The business models used in the built environment must evolve to support circularity and zero-carbon working. Commercial arrangements to suit sustainability will follow.
References
[1] The Switch, by Chris Goodall, Profile Books, 2016.
[2] What We Need To Do Now, by Chris Goodall, Profile Books, 2020.
[3] Building Revolutions, by David Cheshire, RIBA Publishing, 2016.
[4] Cradle to Cradle, by Michael Braungart and William McDonough, Farrar, Straus and Giroux, 2002.
[5] How Buildings Learn: what happens to them after they’re built. Stewart Brand, Viking Press, 1994.
This blog was revised in July 2020.