Artist's impression of what the finished school will look like, image: Auxilium Engineering Services

Could waste in the building industry ever be reduced to near-zero, with materials endlessly being reused? By going back to school, contractor Morgan Sindall is amongst many showing the way.

Usually building projects create a lot of waste to landfill, whether with a new build or refurbishment project. But a new wind is blowing through the industry – the idea that reusing materials keeps them at their highest value for as long as possible. With 120 million tonnes of materials worth AU$2.67 billion wasted each year in the UK (including 13 per cent never used), throwing away materials is, in effect, throwing away cash.

The “bible” of cradle-to-cradle building is David Cheshire’s Building Revolutions: Applying the Circular Economy to the Built Environment, published in 2016.

Its main thrust is that the design of building and refurbishment projects should include considerations of its legacy for following generations as a catalyst and inspiration. It argues that redefining waste as a resource means that costs can be reduced, and companies can be protected against volatile prices associated with raw materials. Designing for deconstruction is “an essential piece of the circular economy puzzle”, it says.

Cheshire has just proved his theory in action with a school refurbishment project in South Wales where only 0.03 per cent of waste went to landfill. He is a consultant on this project with contractor Morgan Sindall.

Due to be completed in October this year, the work on Pentrehafod School is being conducted while the school is still being used by pupils and teachers. It was reckoned to be two thirds cheaper to refurbish the school than build a new one, as well as yielding a significantly reduced carbon footprint.

Pentrehafod School before renovation
Pentrehafod School before renovation, image: Swansea Council]

The main savings have arisen from retaining the foundations, floor structure and building envelope, which typically account for around half of a building’s embodied carbon. 

Morgan Sindall’s project manager, Ross Williams, says: “We’ve aimed to reuse and recycle the materials we have found while retaining the existing structure wherever possible. For example, the old gymnasium flooring – which retains all its court line markings – has been repurposed as cladding for the staff pod, and showcases the heritage of the school. Existing furniture has been collected, remanufactured and resupplied through our subcontractor, Ministry of Furniture.” 

Use has also been made of materials arising from demolition.

“Walls and floors which were demolished were collected by local recycling firm Derwen who then returned it to site as processed aggregate, which is a good example of just how well a closed loop within the circular economy can work,” Williams says.

The project is also thinking about future deconstruction when the current refurbishment reaches the end of its life through careful selection of materials and structures. “Loose-lay” flooring can be rolled up and sent for recycling, while internal walls of lightweight stud partitions with surface-mounted services allow the building to be easily adapted.

Williams says: “It’s about not looking at anything as waste, but always thinking about how we can reuse and recycle, and – just as importantly – leave a sustainable legacy that will facilitate similar endeavours in the future. We’re not just lowering the carbon footprint of this building now. We’re ensuring it can be kept low in the future.” 

Pupils at the school are even being given a chance to find out about the energy performance of buildings and have mock interviews as apprentices with the contractor.

You can watch a fly through and a video of the project here.

Closed loop building is part of the wider circular economy, the aim of which is to increase resource efficiency, create more jobs and transform mindsets towards a more sustainable future. After all, in nature there is no waste, and everything is endlessly reused.

A new sub-industry

This new approach to building is spawning a whole generation of new start-ups. Terry Clarke and Lydia Dutton launched Loopin 2016 to help the industry repurpose its waste, and soon got the chance to prove their ideas on the biggest infrastructure project in Europe, Crossrail, the 42km underground rail line in London due to be completed later this year.  

“The challenge was to identify ways Crossrail can engage with the circular economy and the sharing economy. We went through a competitive process and pitched against established businesses for that competition and won,” Clarke says.

As with previous industrial symbiosis projects, Loop has an online marketplace for companies to post materials and equipment that others can purchase or claim for free. But it also maps out material flows to figure out how they can be used better.

“That might be linking them up with community projects and charities, SMEs, passing on items that are useful to other businesses, or even allocating them within their own business for other projects,” Clarke says.

Loop is not the only such online marketplace; they are springing up everywhere to satisfy regional needs. Another is Enviromate.

In-service training for the industry in closed-loop building is also being offered, such as this course by BD Online, that pushes the advantages of adopting the practice, which include increased rental yields, finished buildings with greater residual value and achieving a positive architectural legacy. 

Amongst the recommendations for working towards closed loop building is to reduce the initial ecological footprint by using prefabricated, modular supporting structures, timber floors and facades. This makes buildings easier to dismantle at the end of their life for reuse, as well as reducing construction time.  

This practice was used in an extension to Brummen Town Hall in the Netherlands.

aggregates from buildings demolished on site of Brummen Town Hall construction being reused for new buildings on site.

Here, cradle-to-cradle certification of components and materials is ensuring they have a minimum environmental impact during their whole life-cycle.

Detail of existing Alliander building overclad with insulation and reclaimed timber.

In another Dutch project, the headquarters of energy network company Alliander in Duiven, 90 per cent of the materials comprising the original buildings were used in the new project, and these comprise half of the new building. Forty-two per cent of the remaining half are recyclable, as defined by the Dutch Institute of Building Ecology, meaning that in total 92 per cent of all the materials are labelled as “circular”. Second-hand salvaged timber was specified. 

The final structure is 30 per cent lighter than normal, using 35 per cent less material and allowing for disassembly at the end of the building’s life.

The “closed loop economy” is the holy grail of ecological footprint reduction, or making society truly sustainable. With buildings being responsible for around a third of society’s total ecological footprint, the opportunities for a reinvention of the construction industry in this direction are endless.

David Thorpe’s two new books are Passive Solar Architecture Pocket Reference and Solar Energy Pocket Reference. He’s also the author of  Energy Management in Building and Sustainable Home Refurbishment.