What if 50% of materials must be found within 30 miles of a site, could this drive more localised recycling and material production?

The responses to this question on LinkedIn.

Is it scalable?

Nationally Design Coding and the NPPF could drive the increased use of local stone, aggregates and waste aggregates. Ambitious planning policy in Cornwall and B&NES are also driving more challenging zero operational and reduced embodied carbon targets. At Nansledan in Cornwall 4000 homes are being delivered using this approach with successive improvement to each phase. While bigger projects can engage with this shift (though this is not the norm) smaller clients struggle to afford the design and material costs (1.).

Is it beneficial to all?

It encourages stronger connections to the supply chain and more accountability not just for carbon but for nature and communities. If local materials are equitably sourced why shouldn’t material from further way also be? However, there is no consistent practice or method for knowing about what impacts on nature and people building materials are having.

Is it rapid?

The knowledge of resources available locally is patchy but if it became more commonplace it could drive stronger supply chains for re-using construction waste, using biogenic and sourcing aggregate and stone locally. Could an aim of any initiative be to increase accessibility of regenerative zero carbon swaps and accelerate their take up – condensing knowledge – model projects and a catalogue?

Is it revolutionary?

It could be part of shifting how we value materials. There needs to be a better of understanding of what is available where. Practitioners are evolving methods of mapping and using available local materials, wastes and by-products but this is niche. There are examples of projects that make new construction elements from agricultural by products and waste from excavation.

Is it replicable?

A research project (2.) is exploring creating regional hubs to map natural and waste resources pool knowledge skills and exemplar designs – to bring together regional landowners, SME’s, supply chains’ – this could establish a model that could be adapted across ‘bio-regions’. Another research project is developing approaches to bio based retrofit (3.). Architects Declare and Leti advocate open sourcing of knowledge how can this apply to the prototype?

Postscript – In the LinkedIn post and here I featured a view of Nansledan an urban extension to Newquay. In Design Review we often highlight this scheme for its considered street design (by Andy Cameron) and sensitive integration of parking. It also does well to materially ground the project in its location using slate, granite and other stones that are recognisably Cornish. By using locally sourced stone and aggregates and using blockwork largely made from recycled aggregates the project has begun to exceed LETI and RIBA 2030 embodied carbon targets. Something few developers are achieving at scale.

I asked the Duchy of Cornwall to tell me more about how they did this and their plans for the next phases. They said all the aggregates and blockwork come from within a 30-mile radius. Generally, they have used a Consortium Agreement with their housebuilders to agree a zero carbon and sustainability strategy requiring the sourcing of materials and their carbon characteristics to be evidenced. The next steps are to reduce cement content and the use of petrochemical insulation products. They also plan to transition to structural timber frame solutions and make a general shift towards adopting more natural biobased product alternatives.

I spoke to the Stone Federation about initiatives they are supporting to help designers specify stone responsibly such as the British Stone Sourcing Tool and the currently underpopulated Ethical Stone Register. They highlight how stone is material that can be used at high value two or three times and last over many hundreds of years. But design for disassembly needs more established design principles for standard sizes and fixings. There is also potential to use traditional materials in new ways such as using stone to make bricks or as a loadbearing material. Some UK quarries take back or actively seek used material to trade alongside newly quarried material.

  1. Simaitis, J. et Al 2023 Pioneering Net Zero Carbon Construction Policy in Bath & North East Somerset, University of Bath
  1. The King’s Foundation/ UCEM/ 2 year KTP research project to set up regional building hubs
  1. Fit for the Future, Universities of Cardiff and Bath
  1. Stone in District Wide Design Codes – e.g. Northumberland/Lake District.
  1. Building Stones Database for England Historic England
  1. British Stone Sourcing Tool – https://www.stonefed.org.uk
  1. Ethical Stone Register
  1. BES 6001 – Framework Standard for Responsible Sourcing
  1. Green Guide to Specification

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