Research into material reuse including upcycling secondary materials into new building products, and the design of systems that create financially-viable processes for using waste as a resource
Context
It is well-known that buildings—their construction and use—account for around 40% of global carbon emissions. Attempts to decarbonise this sector include reducing the embodied carbon of building materials by using renewables such as timber and other bio-based materials. Suppliers, however, are unable to keep up with the rising demand for virgin renewable materials. New sources of construction materials are therefore required.
At the same time, the industry as a whole is also one of the greatest producers of waste, and any material reuse is typically limited to a one-way flow of worsening quality, such as from solid timber to chipboard, or to agricultural wood chips. What if, as advocates of upcycling argue, we were to see this material not only as waste to be reused on its way to disposal, but as a real resource from which new and better materials and products could be made?
Practice
A number of research and industry collaborations are seeking to rewire supply chains by making “waste” into a resource. Upcycling diverts material from waste streams by remaking things into useful products, extending a material’s lifespan and retaining carbon. It is a version of circular economy that sees “buildings as material banks” (BAMB), in the words of an EU-funded project that is developing tools to support industry-wide shifts to using upcycling secondary materials. Many of these systems are proposed as interventions into systems of construction that would enable wider reuse of materials. One problem faced by upcycling is the lack of information about just what materials are used in buildings: a problem that might be addressed by systems such as “Material Passports”. These are digital identifiers designed to improve opportunities for reuse, a praxis that “creates the context for assessing secondary components against their virgin equivalents and the enabling conditions for new circular business models”. Another approach is called Reversible Building Design: a systems of protocols embedded in construction policy to support the design of buildings that can be deconstructed. Reversible Building Design also creates a new type of construction/deconstruction worker specialisation in the reuse of buildings and components.
At the scale of individual building components, researchers Colin Rose and Julia Stegemann at University College London have investigated the feasibility of Cross Laminated Secondary Timber (CLST) to harness the potential for both secondary timber and “the timber in existing building stocks” to become new structural components. Secondary timber requires processing before use because it is rarely useful in its existing state: both construction and deconstruction processes tend to result in material that is irregular, broken, or inconsistent. Rose and Stegemann’s research offers a technically rigorous and economically viable proposal for one particular example of upcycling.
Upcycling, circular economies, and material passports are not simply about providing technical solutions to immediate problems: they are also a form of critique that acts by providing real alternatives to the systemic failures within the construction industry—failures that disproportionately contribute to climate breakdown. Upcycling secondary materials is a way of feeding these products back into the top end of the material chain, but it also demands that we see cities—not just productive hinterlands—as places rich with (future) resources: vast accumulations of material that ought to be examined and reused. Offering ways to tap into some of these waste streams not only reduces environmental impacts, it can also bring with it significant elements of democratisation, by making more resources available to people in their immediate environments, freed from traditional supply chains.