Repurposing a building starts with knowing all of its constituent parts. Isabella Kaminski looks at how material passports could change the industry
Imagine knowing how much a building was worth – every brick, beam, window, door and curtain wall – and which parts of it could be reused or recycled.
With such detailed knowledge, the building would become more than just a here-and-now balance sheet asset. It would create a bank of components that had a potential future life and a known value beyond worthless demolition spoil.
It could change construction economics, revolutionise design, result in more sustainable use of finite natural resources and slash carbon emissions.
The material passport, a concept already being adopted in mainland Europe, paves the way for this industry sea change.
The passport is effectively a digital document containing information on all the parts in a particular product or material or, in this case, a building.
Circular economy champion Duncan Baker-Brown of BBM Sustainable Design explains that a material passport lists the ‘ingredients’ of a structure, which can be useful to manage a facility or to make changes if it is redeveloped or extended.
The passport is effectively a digital document containing information on all the parts in a particular building
By linking this information to other sources such as product and market data, he sees it as a tool to move the construction industry closer towards a more circular economy; one where materials are kept in use longer and new resources are not extracted to make buildings.
‘The problem we’ve got at the moment is we tend to crush buildings into pretty useless rubble. In a circular economy you keep the value and sophistication of the products and systems when you reuse them,’ says Baker-Brown. ‘That’s why material passports are an excellent idea because they’re going to make the likelihood of good deconstruction, or even keeping a building, higher.’
The concept of material passports was pioneered several years ago by RAU Architects, headed by Dutch architect Thomas Rau.
Sabine Oberhuber, who co-founded sister company and circular business consultancy Turntoo alongside Rau, says the practice realised there was no business model for recycling buildings; there was no obvious place to buy reused materials or to sell them at the end of their life.
To fill this gap, they designed a material passport that would collate data on all the materials and products in a building.
One of the first projects to use this cataloguing system was the redevelopment of an office owned by Dutch energy firm Liander in Duiven in 2015. It reused 80 per cent of materials from the existing building and ensured all virgin products were reusable.
Office, RAU Architects and Fokkema & Partners Architecten
‘Our ambition is to get the industry investing in buildings, pushing designers for maximising material value,’ says Oberhuber. ‘It’s very important architects embrace that thinking fast because if we look at the impact of the building industry on our environment it’s huge.’
This nascent scheme has grown into the Madaster platform. Accessed through a subscription, this allows designers and others along the construction chain to upload BIM data on a building. The platform automatically generates a material passport describing the materials in each layer of the building and how easy it is to retrieve them. It also estimates how much they will be worth in the future by drawing on information from sources such as the London Metal Exchange.
And it calculates a circularity index, which analyses whether the building uses virgin or recycled materials, how much information is available on them, whether they can be reused and how they are joined together.
Not only does this make it easier to change or deconstruct a building, but it can increase its value by putting clear figures on how much its materials are worth.
On a wider front, according to Dutch-based sustainability consultant Metabolic, the 2.6 million tonnes of building materials ‘released’ each year through renovation and demolition in Amsterdam alone has a value of €688 million.
Material passport example
Pablo van Den Bosch of the not-for-profit Madaster Foundation says its platform draws from its own data pool to estimate what materials and products will be available for reuse in the future. He says: ‘One of the biggest issues in terms of circularity in the construction sector is that the design process is disconnected in time from the realisation of the object.’
There are plans for adding information on embodied carbon into Madaster, too.
Baker-Brown is hopeful that architects could easily adapt to designing with materials at front of mind, helping them think more carefully about what they put into a building. ‘Architects are really well placed to deal with this,’ he says. ‘[As] we tend to do the detailed design of building, we know how they’re put together.’
Some approaches will undoubtedly have to change. He notes that just one or two things during the construction process could completely undermine its ability to be easily deconstructed, such as cement in brickwork instead of lime mortar, or glue instead of screws, bolts and clips.
Even expanded foam – often used to seal a house to achieve the Passivhaus standard – is problematic. However, as Baker-Brown says: ‘What the Passivhaus will say, quite rightly, is if you do detailing properly you don’t need to use expanded foam.’
Passports could also encourage the reuse of existing products in building design. Anna Surgenor, senior sustainability adviser at the UK Green Building Council, describes passports as a ‘health check’, showing the history of materials in a building and the stresses they have been through. ‘You can clearly see if a beam or glass panel or carpet tiles have had structural issues or a lifetime of heavy wear and tear and are not viable for reuse. But there are products that are in a perfectly good structural state to be used again.’
She says this in-depth directory would allay professional liability concerns. ‘There are already companies which offer reuse; the Olympic stadium reused gas pipelines in its design. It’s not anything new, but we need many more of those sorts of examples to be able to encourage the design community away from the perception of the risk associated with that.’
London 2012 Olympic Stadium
Source: London 2012 Olympic Stadium
A drive towards reuse would not prevent architects from being creative, says Surgenor. ‘You can still, as a profession, remain bespoke in terms of what you’re designing. It’s a case of thinking slightly [harder] about how buildings are produced.’
A clear, fully-costed material inventory would help persuade organisations with a longer-term interest in their buildings, such as universities and social housing providers, to think more about reuse. But Surgenor says clients are increasingly interested in applying circular principles and setting zero-waste targets, both for their own business propositions and in response to regulatory requirements. The draft London Plan, for example, will soon require larger developments to produce circular economy statements. ‘As an architect you’ve probably got to future-proof yourself by offering these services,’ she says.
The wider hope is that material passports will encourage manufacturers to produce better construction products and be more transparent with their data, and to trigger and enable new circular business and investment models. For example, manufacturers could retain ownership of their products and take them back at the end of their life, as Philips has done with its concept of leasing lighting, or design for reuse from the start.
‘We’re less interested in creating large ingredients lists of buildings, because we’re on that road anyway with the digitisation of construction,’ says Jesse Putzel, head of sustainability at BAM Construct UK. ‘The concept of a material passport isn’t just a dump of data; it’s a tool to encourage manufacturers to think about how they can improve their products and materials.’
Gilli Hobbs, director at the BRE, sees material passports as just one part of the growing digitisation of construction information, and says they are useful if they help inform better decision-making. Hobbs worked on a €10 million project funded under the EU’s Horizon 2020 scheme called Buildings as Material Banks (BAMB), which came up with a prototype material passports platform.
Rafaela Candiago Zanatta, of Germany-based consultancy Epea, which was also involved in BAMB, says architects have a fundamental role in the implementation of material passports. She stresses that implementation needs to happen from the beginning of a building design, ‘growing in detail in terms of product content, installation, maintenance, disassembly and reuse potential together with the project development’.
But BAMB concluded that a single platform for material passports would be less useful than a standardised format for the data involved. Zanatta says: ‘This helps product manufacturers provide information only once, product specifiers to make informed decisions, product users to have accessible data for usage and maintenance and – very important – product reusers to have updated information about reuse potential and value recovery possibilities.’ Epea is now talking to the Luxembourg government about developing a standardised format.
The UK is not yet at the same stage as The Netherlands or Luxembourg in the material passports process. Madaster, the most developed commercial platform, is not available here yet, despite ongoing talks with potential partners. Hobbs predicts the UK will develop its own version of the Luxembourg standard at some point.
However, construction and demolition businesses in the UK are starting to recognise the value of materials in buildings, with companies like Globechain providing an online marketplace for reuse of materials.
Until you have a market full of materials in material passports that command high values, you don’t create demand
Richard Boyd, materials consultant at Arup, describes it as a chicken-and-egg situation. ‘You’ve got to assume there’s a mature market [for used materials] which estimates the price. At the moment there aren’t material passports, so the value is low. Until you have a market full of materials that command high values, you don’t create demand for people to specify new building material passports.’
He sees a role for both industry and government in making material passports standard in construction. ‘You need to get some people to start doing it, in partnership with the public sector, so policymakers can see there are market leaders doing it and it’s worthwhile and creating a net value for the economy.’
The financial arguments, rather than the environmental pressure, could be the seed the system needs to take off in the UK. The European trailblazers are certainly worth watching closely.