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A1.1: CIRCuIT demonstrators

A1.2: Business cases emerging from the CIRCuIT demonstrators

A ‘business case template’ was prepared based on data attributes and analytics developed during the CIRCuIT project to support, monitor, measure and assess CIRCuIT demonstrator projects.

This template has been used as the framework to gather data and present findings from demonstrators across the three core themes of the project: urban mining and material reuse, building transformation and life cycle extension, design for disassembly and adaptability. The completed templates for all demonstrators can be found at circuit-project.eu/post/latest-circuit-reports-and-publications.

In this section, cases emerging from all demonstrators are aggregated to provide a selection of concise, evidenced, and actionable business cases. A ‘business case’ is understood as making a case for changing something. It is directed at a specific audience who can enact the proposed change. It describes actions to be taken outside of BAU and the outcomes that are expected. These commentaries and the demonstrator templates provide evidence on the benefit of investment in the proposed changes for both the decision maker and the community.

Public and private asset owners, investors, and developers

A. Public and private asset owners can assess cost and carbon saving opportunities from reuse across projects and asset portfolio by commissioning and acting upon pre-demolition audits

Related demonstrators: 2 – Offakamp, 4 – Circulation of materials from Gladsaxe School / The Swan, 6 – Hyltebjerg School, 7 – Hevoshaka School, 8 – Vantaankoski school, 10 – Component reuse of retail unit, 11 – Demolition of One Leadenhall Street

Public and private asset owners can reduce costs and carbon emissions by implementing PDAs proactively or in early project stages. By understanding the materials available for reuse and establishing a potential material reuse pipeline, materials more likely to be exchange within the asset portfolio. Financially, conducting PDAs early can offer a cost- material solution. One demonstrator found a 12% construction cost reduction by implementing onsite use of recycled aggregates. While PDAs are gaining industry familiarity, some secondary material supply chains do not have the financial capacity yet to widely and strategically implement them. Policy recommendations suggest mandating PDAs for all projects, upscaling PDAs and in turn reducing the costs of deconstruction, processing and testing.

B. Public and private asset owners can identify the optimum cost and carbon approach to projects by commissioning assessments of different degrees of retaining and transforming existing assets

Related demonstrators: 19 – Korso School, 24 – Transformation of 31-34 North Row

Owners of public and private assets can identify optimum cost and carbon approaches to projects by commissioning early-stage assessments of the different ways to use buildings (I.e transformation and retention). The demonstrator projects have shown that optimal retention approaches (achieved through early assessments) can save 7% - 41% of total project costs, amounting to €1 million - €5.5 million saved making a strong case for investing in these assessments. The skills and knowledge do exist to implement assessments to retain buildings and in turn reduce costs and associated carbon. It is vital to consider the cost and carbon saving benefits with evidence at the beginning of projects and appoint experienced consultants. For less economically viable projects, financial incentives such as (in a UK context) charging VAT equally on new build and refurbishment might be necessary.

C. Public and private asset owners can assess existing housing roof and loft spaces and other opportunities for densification

Related demonstrators: 16 – 1900s housing urban densification, 20 – Transforming 1970s public rental housing

Public and private asset owners can assess existing housing roof and loft spaces and other opportunities for densification to cope with increasing housing demand. This essentially means accessing the benefits of transforming roof spaces into residential space. For example, demonstrator project 16 assessed several roof transformation projects in Copenhagen to conclude that roof transformations for residential space can enhance environmental performance, in turn supporting the case for transformation. Roof conversions for housing is technically straightforward but they have legislative and financial obstacles which limits the upscaling potentially, however more assessments of the benefits could help to build a case for more lenient roof conversion regulations.

D. Public and private asset owners can activate a neighbourhood and support new businesses by retaining existing assets for meanwhile use during long-term, phased regeneration projects.

Related demonstrators: 23 – Transformation of Meridian Water Block F

Public and private asset owners can activate a neighbourhood and support new businesses and job creation by assessing masterplans to identify existing assets to retain for temporary use during long-term, phased regeneration projects. In the demonstrator project, construction costs for adapting an existing building were 6% less than providing an equivalent new building. The projected return on investment over a fifteen-year temporary use period was enhanced by 8% compared to the new build alternative. Building retention option creates significantly higher net revenue, more jobs and a greater net total Gross Value Added when compared to when an existing building is demolished, not replaced, and the land is rented out. Building retention for temporary use is technologically feasible, but the challenge lies in recognising opportunities early and prioritising benefits in planning. With long redevelopment timeframes, there is good scope to treat existing buildings as assets that can provide income and social benefits through temporary use.

E. Public and private developers can create more valuable homes, improve resident satisfaction and reduce life cycle cost by developing adaptable housing

Related demonstrators: 28 – Copenhagen adaptable housing, 30 – Living places Copenhagen 33 – Helsinki adaptable flats, 35 – Meridian Water: Rightsizer

Public and private developers can create more valuable homes, improve resident satisfaction, and reduce lifecycle cost by creating adaptable housing. In the CIRCuIT demonstrators the upfront costs for adaptable housing were 21% - 24% higher. However, in one case life cycle cost savings of 28% were achieved if the spaces was adapted compared to demolishing and rebuilding after one use cycle. Adaptability of the spaces was made possible through simple design changes using available construction methods. Resident surveys show demand for adaptable flats, with a willingness to pay a premium (2–10%) for the communicated benefits. In homes owned by residents, a noted challenge was making owners aware of potential savings to motivate them to invest in adaptability. For public developers and housing associations, it’s crucial to use life cycle costing over multiple life cycles to evaluate the benefits of designing for adaptability when they retain ownership.

F. Public and private landowners and asset owners can achieve increased rental income by facilitating meanwhile use of underused land and assets.

Related demonstrators: 34 – Albion Street / The Hithe

The term ‘meanwhile use’ represents a range of strategies that can be put into place to make under-utilised spaces and places become productive, both in an economic and social sense. Sites set for redevelopment often remain unused for a long time before construction begins, leading to unnecessary expenses for security and hoarding. Some businesses have evolved to offer meanwhile use construction for these underused plots, but finding a willing site can sometimes be difficult. Landowners can achieve increased rental income by identifying opportunities for ‘meanwhile use’ prior to longer-term redevelopment and actively working with the organisations offering meanwhile use construction. In London, there are 466 suitable plots, totalling nearly 500,000 sqm, showcasing the significant opportunity for meanwhile use, and thus increased rental income for public and private landowners in the UK.

G. Local authorities can help to create circular supply chains by driving demand for novel remanufactured secondary materials by adopting their use in public projects.

Related demonstrators: 12 – Glulam from secondary timber

Local authorities can support circular supply chains by instructing procurement teams to specify secondary materials in public projects. This will help local authorities to meet their carbon reduction objectives, while increasing the market for novel remanufactured secondary materials. The demonstrator project showed that deconstructing timber framing was estimated to add 15% to the demolition contractors’ costs, however there is a holistic economic benefit to the area if more construction spend is retained in the local economy. This spend also helps new businesses to expand and reduces their costs, increasing the competitiveness of circular supply chains in the longer term. In the demonstrator, using secondary timber in glulam manufacture can achieve a 40% reduction in embodied carbon compared to conventional production. Understanding and communicating these environmental benefits of using novel secondary materials in projects will be key to resisting the pressure to revert to business as usual. The success of this business model relies on having enough secondary materials for big projects to enable consistent demand.

H. Public asset owners and housing associations should include assessments of whole life carbon, resource consumption and waste generation in strategic decision-making over retention and retrofit versus demolition and redevelopment

Related demonstrators: 17 – 1970s housing estate – Taastrupgard, 14 – Horner Geest

Public asset owners and housing associations should include assessments of whole life carbon, resource consumption and waste generation in strategic decision-making over retention and retrofit versus demolition and redevelopment. Assessments have shown that the transformation of socially challenged developments can be considered a win-win, aligning with both social and climate concerns, particularly when coupled with ambitious climate impact reduction initiatives and sustainable practices like repurposing and reuse. Through such assessments, demonstrator 14 showed that by updating and modernising apartment buildings, we can reduce carbon emissions by 4.5 kg per square meter of living space. Economic analysis shows a 20.9% cost reduction per square meter for demolition and construction/modernisation, building a case for retention and retrofit versus demolition and redevelopment.

I. Local authorities can help to create circular supply chains by driving demand for novel DfD construction by adopting its use in public projects.

Related demonstrators: 25 – Hamburger Klassenhäuser – Slab construction, 26 – Hamburger Klassenhäuser – Façade comparison

Local authorities can play a pivotal role in reducing future embodied carbon emissions and promoting circular construction by leading procurement teams to specify DfD in public projects. While resource savings are a large driver for implementing DfD techniques, the CIRCuIT demonstrators also found financial benefits. Demonstrator 26 found that in comparison to the basecase, the circular construction intervention adopting DfD facades resulted in an overall cost reduction of 61 % over the building’s life cycle. Implementing novel construction techniques requires commitment and understanding from development and regeneration officers who must champion the policy through project briefs and challenges. Collaborating with innovative, circular businesses can enhance a local authority’s reputation. The scalability of this business case depends on the availability of ready-to-use products and increased market demand driven by progressive purchasing and tighter regulations.

J. Local authorities can achieve faster, cheaper school construction and the ability to adapt sites to rising and falling school-age populations by procuring DfD construction

Related demonstrators: 25 – Hamburger Klassenhäuser – Slab construction, 31 – Vantaa Hybrid school

Local authorities can achieve faster, cheaper school construction and the ability to adapt sites to rising and falling school-age populations by procuring DfD constructions for schools. Demonstrator 31 showed that enabling larger degrees of flexibility in school design would allow the buildings to adapt to changing future needs without requiring major construction works, bringing carbon, material and cost savings. This business case could potentially be replicated to all future school projects in which could potentially result in significant environmental savings and increased efficiency of school space for the city at large.

K. Private asset owners, investors and developers can gain recognition and market differentiation by adopting novel, remanufactured secondary materials

Related demonstrators: 5 – Stablen / The Stack, 10 – Component reuse of retail unit, 12 – Glulam from secondary timber

Embedding circular strategies into construction can allow private asset owners, investors and developers to gain recognition and market differentiation. Effective use of remanufactured materials can highlight the private asset owner, investor, or developer as a sustainable lead in the industry. Strong carbon benefits can be found by embedding this approach as well. Demonstrator 5 showed that by using 58% reused and 42% new glulam beams, there was a 47% reduction in overall carbon impact of the project. This approach was also shown to reduce costs 12% compared to using only new beams. This specific approach could be applied in other types of buildings that have a beam structures.

L. Private asset owners, investors and developers can develop expertise in identifying and transforming underused assets

Related demonstrators: 15 – Gröninger Hof Parkhaus, 24 – Transformation of 31-34 North Row

Private asset owners, investors and developers can develop expertise in identifying and transforming underused assets to reduce construction costs and increase social value. For example, demonstrator 15 highlighted that there is a large market for the transformation of unused car parks, especially in cities like Hamburg that are transitioning away from cars to more sustainable travel. This transformation of underused spaces can contribute to the creation of valuable living and social and commercial spaces in inner cities. The total construction costs were also found to be 5% lower in the transformation model.

M. Private asset owners, investors and developers can relocate entire structural steel frames by connecting to others’ project needs

Related demonstrators: 22 – Extending the life of a large 1980s commercial shopping outlet

Certain assets such as steel frame builds are technically simple to take apart and relocate. Private asset owners, investors and developers have the opportunity to capitalise on this by facilitating the relocation and transformation or selling their assets for the purpose of relocation. Demonstrator 22 illustrated that whole life carbon was improved 47% by applying the relocation and transformation approach as opposed to demolishing and building new. This approach was also more cost effective with a 15% saving in the capital construction cost, and reduced the Whole Life costs by 2%. This points to the value in pursuing the sale of a steel frame asset as a relocatable building.

N. Private asset owners, investors and developers can gain recognition and achieve market differentiation by assessing whole life carbon when deciding between retrofit and demolition

Related demonstrators: 13 – Godewind Park, 18 – 1930s commercial plot, 21 – Adaptive reuse of office buildings for housing in Vantaa

Private asset owners, investors, and developers can gain recognition and should consider whole-life carbon assessments when deciding between retaining and retrofitting versus demolishing and building new on new developments. This approach has strong financial benefits, with the CIRCuIT demonstrator projects illustrating that retrofit scenarios can result in total costs up to 37% lower than new builds over a 50-year period. There were also strong carbon benefits with retrofit scenarios illustrating an up to 23% lower whole-life carbon than new builds. This approach can be scaled with increasing software access, consultants can efficiently conduct whole-life carbon assessments of retention or demolition and rebuild scenarios. To integrate assessments into strategic decisions, developers should go beyond the legal requirements and set ambitious policies. Consistently taking on this approach will also allow the companies to benefit from beneficial market differentiation. Specialising in this approach also enhances resilience against policy/tax shifts that incentivise retrofit over demolition. Scaling retrofit solutions requires familiarity with existing buildings and innovative surveying methods for better data as to existing structures.

O. Private investors and developers can rent out affordable workspace by deploying a portfolio of reusable assets on meanwhile use sites

Related demonstrators: 34 – Albion Street / The Hithe, 36 – Green Street Workspace, Newham

Private investors and developers can increase their return on renting affordable workspace by acquiring demountable and reusable buildings and deploying their portfolio on meanwhile use sites. Land and assets earmarked for redevelopment are often underutilised before starting construction. These periods of under-utilisation of assets are often significantly longer than is first anticipated, due to delays in projects coming forward for allocated sites and delays in implementing existing planning permissions, leading to years of outgoings for landowners. Developers should invest in a portfolio of relocatable assets and market them to owners of underused land. The demonstrator The Hithe found that over thirty years and in comparison to a conventional basecase, the circular construction intervention resulted in a 6% increase in construction cost, but an overall reduced operational cost by 5%, reduced maintenance cost by 13%, reduced renewal costs by 60% and reduced the Whole Life costs by 23%.

Municipality as policymaker

P. Local authorities can help to create supply chains for secondary materials by establishing circular economy construction hubs closer to city centres.

Related demonstrators: 1 – Luruper Hauptstraße, 3 – Musterbude, 5 – Stablen / The Stack, 12 – Glulam from secondary timber

Local authorities can help create circular supply chains for secondary materials by allocating sites for circular economy construction hubs and facilitate partnerships to manage them. These hubs enhance material value retention in the local economy, reducing supply chain length, and creating local jobs. Issues such as limited storage space and high transportation costs for materials can impact reuse opportunities. However, as reuse becomes more visible, costs are expected to decrease. Partnering with organisations experienced in site management is crucial. Temporarily using disused brownfield sites for these hubs can revitalise unused spaces and benefit the urban environment. Such initiatives contribute to evolving urban waste management into a circular economy infrastructure, with demonstrator projects illustrating carbon emissions reductions ranging from 2% to 47%. Policy objectives aimed at achieving waste self-sufficiency should support the development of these sites.

Construction industry – deconstruction and secondary materials management

Q. Demolition contractors can maximise revenue from existing materials by assessing cost/benefit of different deconstruction techniques 

Related demonstrators: 9 – Tikkurila School Warehouse

In a circular economy, existing materials are valued and there are market systems in place to sell and exchange materials. Demolition contractors are in a great position to leverage this newfound value by establishing a process of valuing existing materials and costing the necessary deconstruction techniques to extract these materials. Demolition contractors usually view buildings up for demolition through the lens of waste, however when materials are seen as resources the contractors detailed knowledge of deconstruction techniques can be applied to create a new income stream. Knowledge of deconstruction techniques are not yet widely known though there have been success stories of demolition companies refashioning themselves into deconstruction companies specialising in value retention. In the demonstrators various techniques for deconstructing bricks - e.g using hand held power tools, using an excavator – were compared for their efficacy and cost. Handheld power tools were more effective in harvesting undamaged bricks but took significantly longer to deconstruct the building and cost more due to increased labour needs – 17% more than other reclaimed bricks and 69% more than virgin bricks. Using the excavator resulted in reclaimed bricks that were 48 % cheaper than other reclaimed bricks and 24% cheaper than virgin bricks. Understanding the most effective way to reclaim materials can keep costs down and secondary materials of interest to consumers. x

R. Demolition contractors can improve cost estimates by comparing PDA predictions to actual materials arising from demolitions

Related demonstrators: 1 – Luruper Hauptstraße, 2 – Offakamp

Seeing demolition materials as resources as opposed to waste can increase the profitability of deconstruction or demolition work. However, as this is a new sector the practice of deconstruction or selective demolition to retain the value of materials still requires a level of data collection and analysis to determine optimal approaches. Demolition contractors looking to shift from waste management to reselling material resources should approach each project as an information collection exercise and compare PDA results to eventual material arisings from demolition. This comparison will help hone the most effective deconstruction techniques. These demonstrators showed that current method to estimate recyclable content are flawed and onsite demolition and reusing of mixed mineral waste results in lower environmental impacts compared to demolition and being processed in a recycling facility.

S. Demolition contractors can maximise higher quality recycling by streamlining mineral wastes

Related demonstrators: 3 – Musterbude

Demolition contractors can maximise high quality recycling by being more effective in the collection and separation of mineral wastes. Clear separation reduces the likelihood of downcycling of aggregates by allowing more control in terms of performance and aesthetics. The Musterbude demonstrator tested seven different concrete mixes with various levels of recycled aggregate. Aggregate with the highest value recycled material was 55% cheaper than virgin aggregate.

T. New and existing businesses can achieve new revenue streams by launching products based on novel recycling and remanufacturing processes

Related demonstrators: 12 – Glulam from secondary timber

There is growing interest across the industry to reduce the carbon impacts of projects by increasing the proportion of material that is reused or recycled. This poses an opportunity for new and existing businesses to achieve new revenue streams by launching products based on novel recycling and remanufacturing processes. For example, the Glulam from secondary timber demonstrator showed that reclaimed timber can easily be worked and transformed, allowing it to serve various functions like structural columns and beams. Challenges include obtaining reliable material sources within a useful timescale, characterisation of the material in terms of material grade, and identifying metallic fasteners in the material as removal is crucial to avoid damaging the tooling used in the formation of the glulam. A significant amount of construction waste is downcycled, so there is significant scope for upscaling this solution.

U. Demolition contractors can achieve new revenue streams by becoming retailers of recovered materials

Related demonstrators: 5 – Stablen / The Stack, 8 – Vantaankoski school, 9 – Tikkurila School Warehouse, 10 – Component reuse of retail unit

Demolition contractors can find new ways to make money by becoming experts in urban mining and reclaiming materials for reuse, remanufacturing, or high-quality recycling. In terms of reselling components demolition contractors traditionally focus on high-value goods for heritage projects, however there is a growing demand for other secondary materials like structural steel. In one demonstrator project, deconstructing a steel frame added £50/tonne to costs, but the resale value is approximately £80/tonne, making it financially viable for demolition contractors to sell. Simplifying deconstruction through improved skills and technology, along with a better understanding of secondary material markets, can reduce costs and enhance feasibility even further. Greater demand for secondary materials, driven by progressive purchasing and carbon regulations, can increase profit margins and expand the range of recoverable materials.

Construction industry – designers and supply chain

V. Designers can become building transformation specialists, capable of rigorously assessing a range of approaches to building retention and adaptation

Related demonstrators: 19 – Korso School, 24 – Transformation of 31-34 North Row

Thriving in the circular economy will require rethinking the entire construction process from design through to demolition. On the design side this means designers must become specialists in transformation – being able to assess a range of approaches to building retention and adaptation. Initially this can support the design organisation differentiating themselves as a leader in the sustainable construction field. As policy requirements for circular approaches and low embodied carbon construction grow, specialising in transformation will futureproof design agencies against future requests and requirements.

W. Manufacturers can generate new revenue streams by developing demountable product-as-a-service business models.

Related demonstrators: 27 – Neustadt – Partition walls, 29 – DfD modular façade – Taastrupgård, 32 – DfD warehouse, 36 – Green Street Workspace, Newham

Manufacturers can make money by leasing building products, like partition systems, and keeping ownership for future savings. In the demonstrator projects, systems designed for disassembly had 11–25% higher upfront costs but saved 13–25% when used a second time. Real savings were seen in the Neustadt example, benefiting manufacturers who can disassemble and re-warrant their products. To make leasing common, there needs to be a mindset shift and considerations for pricing and ownership. While there are financial and organisational risks, keeping ownership of materials protects against future price changes. Leasing works best for shorter-lived components and temporary buildings, raising questions about compatibility among manufacturers. Technology alignment and information retention, like material passports, ensure proper disassembly and reuse, even if the original manufacturer stops trading.

X. Manufacturers can invest in offsite manufacture of slabs and façade elements to enable faster construction

Related demonstrators: 25 – Hamburger Klassenhäuser – Slab construction

Manufacturers can invest in offsite manufacture of slabs and façade elements to enable faster construction and thus make themselves the preferred supplier. Shorter construction times means lower costs for the client, so providing a product that makes this possible while also offering environmental benefits can be a key business strategy. Demonstrator 25 illustrated that byincorporating flexible designs for slabs, a 75% reduction incarbon footprint can be achieved. The economic analysis found that a cost reduction of 37% is possible, when considering two buildings constructed with a 90% reuse potential of the slabs compared to demolition and building new.


Y. Citizens can form cooperatives and create new affordable homes and workspace by identifying and transforming underused assets.

Related demonstrators: 15 – Gröninger Hof Parkhaus

Citizens can form cooperatives to collaborate with municipalities to identify and repurpose underused assets around the city transforming them into valuable buildings. In one CIRCuIT demonstrator a citizen cooperative led the transformation of an underused multi-story car park in Hamburg into a mixed use residential development. This approach found a 15% saving in demolition costs and a 5% reduction in total construction costs compared to demolition and new build. Citizen-led cooperatives can enhance feasibility of such projects by building relationships with city planners and investing in alternative residential-led mixed-use developments. Early investigation of existing structures is crucial to understanding and mitigating risks associated with hazardous materials or contamination. Scaling this approach is feasible, particularly in cities aiming to reduce car use, with Hamburg alone expecting nearly 10,000 parking spaces in multi-storey car parks to be suitable for transformation in the next twenty years. Municipalities can support cooperatives by systematically identifying assets at risk of demolition, maximising the potential for their transformation and social, environmental, and economic benefits.

Z. Housing cooperatives and resident associations can assess roof and loft spaces of existing housing for building- or estate-wide densification potential.

Related demonstrators: 16 – 1900s housing urban densification

As cities struggle with housing availability and affordability, expanding existing buildings vertically is a compelling option as it increases density without changing the character of the city area. Assessing this transformation potential for housing cooperatives and resident associations would allow these organisations to create significant additional value for a fraction of the financial and environmental cost of an entirely new development.

CIRCuIT’s housing densification demonstrator illustrated that creating new housing via roof conversions is technically uncomplicated but runs into legislative and financial barriers. For this approach to be taken forward successfully, certain apartment requirements such as additional parking spots would need to be lightened or removed. These legislative changes should be possible with close collaboration with the city. A full transformation of the attic space is also too expensive for individual housing owners to consider, even with the rent income from future apartment residents, as construction costs remain high due to the customized nature of building on top of existing structure. Different financial arrangements, such as selling the entire floor to a developer could circumvent this challenge. The environmental benefits of this approach are clear, with the embodied carbon of a rooftop conversion being 48% lower than a comparative new build.