HOW TO MEASURE CIRCULAR CONSTRUCTION

The term 'circular economy' is broad and ambiguous, sometimes used interchangeably with 'sustainability’. The boundaries of circular economy in academic fields have more than 221 suggested definitions (Kirchherr et al., 2022). So, when we discuss circular construction, we must be able to specify which circular strategies we are talking about, what time dimensions, which life cycle phases, what level of implementation, what sustainability dimensions, etc.

A classification model for circular construction was developed to help clarify the monitoring model and to ensure a common language during the development of new indicators. The classification framework was also applied to organise indicators, policy documents, and research papers and as a preference framework when clarifying stakeholder interests within the sector. This allowed the project team to understand what aspects of circularity dominate current research, policies, and monitoring frameworks and what the sector would like to understand better moving forward.

The taxonomy presents five overall category frameworks used to categorise each circular construction indicator

The circularity strategies and level of implementation are inspired by Potting et al. (2018) and developed further by Moraga et al. (2019). The lifecycle stages are from DS/EN 15978 (2012). The time dimension categories are inspired by Taplin et al., (2013). Finally, the scope of circularity is inspired by Keeble (1988).

TABLE 2. A taxonomy for a circular construction monitoring framework

Category framework	Categories	Examples
Circularity strategies	Preserving the function/service life of the buildings: Refuse (R0); Rethink (R1); Reduce (R2).	Services are, e.g., square meters office space; parking space. These can be preserved for instance through rearrangements and adaptable designs. Rethinking the purpose can reduce the need for demolition and refuse the need to build new.
	Preserving products: Refurbish (R5)	Products are whole buildings or parts of buildings. These can be refurbished.
	Preserving component: Reuse (R3); Repurpose (R7)	Components are building products: Windows frames, doors, whole bricks, prefabricated elements, etc. These can be preserved through reuse, and repurposing (upcycling).
	Preserving materials: Recycle, downcycle (R8)	Materials are, e.g., crushed bricks and concrete and wooden parts for chipboards, and these are mainly recycled (downcycled).
	Preserving embodied energy: Recover (R9)	Embodied energy is, e.g., biogenic carbon in wood materials. The energy is recovered through, e.g., incineration.
Implementation scale	Micro level:	Material or product level/service, organisational level, or building level
	Meso level:	Building complex, cities and regions
	Macro level:	National level
Lifecycle stages	Production phase (A1-A3)	The phase includes: Extraction of raw materials; Transportation to manufacturing; Material production
	Construction phase (A4-A5)	Transportation to construction site; New construction (installation)
	Use phase (B1-B5)	Commissioning; Maintenance; Repair; Replacement; Renovation; Energy consumption for heating and building operation; Water consumption
	End of lifecycle phase (C1-C4)	Demolition; Transportation to waste treatment; Waste treatment, Landfill
	Benefits and loads beyond the building life cycle (D)	Reuse/Recycling and potential for recycling
Time and causal dimension	Process	Processes are activities, e.g., policy responses, workshops, collaborations
	Output	Outputs are the results of processes, e.g., number of workshops.
	Outcome	An outcome may represent a change in a group of people, organizations, or places, such as increased reuse or recycling.
	Impact	Impacts are the long-term effects on environment, society, and the economy.
Scope of circularity	Sensu stricto definition of circular economy: Environmental sustainability	The scope includes ecological metrics
Scope of circularity	Sensu latu definition of circular economy: Environmental, Economic & Social sustainability	The scope includes ecological metrics, as well as economic performance, and social equity

Monitoring of circularity within policy frameworks

As expressed by the Working Group on Performance Measurement of the Performance Development Network of the EU Agencies (2017) and the Bellagio Circular Economy Monitoring Principles (EEA, 2020), relevant indicators must be closely linked to the objectives. This is especially relevant since policy targets need to be defined with scientific-based facts, and indicators serve as measurable benchmarks for assessing progress towards those targets, enabling comprehensive and meaningful policy evaluation. A well-balanced interplay between policy targets and indicators is essential for crafting quantifiably achievable policies.

Waste-related legislation has been developed in the EU since the 1970s, and several circularity indicators have been developed to substantiate the Waste Framework Directive (CEC, 1975 and EC, 2008). EU policies introduced the concept of resource efficiency in 2011, and in 2015, the Commission approved an action plan to implement a circular economy in the Member States (EC, 2011 and EC, 2015a). In 2018, the European Commission proposed a monitoring framework for circular economies. More recently, the EU initiative Level(s) has been introduced as the new European framework for sustainable construction, with 4 of its 16 sustainability indicators focusing on circularity (EC, 2022b). Other EU metrics related to the circular economy across sectors include Resource Efficiency and Raw Material Scoreboards (EC, 2021).

Macro indicators derived from EU policies monitor circularity in the construction sector, often closely related to minimum criteria and targets to be achieved by each Member state. For instance, the Waste Framework Directive requires that at least 70% of non-hazardous construction and demolition waste by weight be prepared for re-use, recycling, and other material in each Member State by 2020.

Nordic Policy Targets for Circular Construction

An investigation of Nordic policies has revealed that circular construction is a theme of 86 policy goals and targets from the five big Nordic countries, distributed between circular themes, as shown in the figure below.

FIGURE 2. The distribution of nordic policy targets across circularity strategies

The exercise found that while many policy targets relate to recycling rates, there is also a significant political momentum towards preserving the function of buildings through circular strategies such as R0, R1 and R2.

Categorising the policy targets into thematic areas reveals how these are distributed more specifically.

Table 3. Heatmap of nordic circularity policy targets

Greenhouse gas reduction	3	4	3	4	3
Improved knowledge and knowledge sharing	0	0	1	0	2
Increased design for disassembly	0	1	0	0	1
Increased knowledge of materials in existing buildings	1	0	0	1	3
Increased recycling of CDW	4	1	1	3	2
Increased reuse of CDW	2	0	1	3	4
Increased sorting of CDW	1	0	0	2	2
Increased use of biobased construction materials	1	0	1	0	2
Increased use of digital tool to track materials	1	1	0	0	0
Increased use of existing building mass	0	0	0	2	0
Increased use of selective demolition	0	0	1	0	2
Reduce amount of CDW	2	1	1	3	2
Reduce fossil energy use in buildings	0	2	1	1	0
Reduce the amount of hazardous waste	1	0	0	4	1
Resource efficiency	4	3	1	0	2
	DK	FI	IS	NO	SE

Few goals and targets relate to the higher levels of the waste hierarchy, while almost a third target recycling and recovery of construction waste. Most of the goals focus on reducing negative externalities, especially concerning Greenhouse gas emissions. Half of the goals relate to the end-of-life phase of construction (lifecycle phase C1-C4). Most goals and targets are local (municipalities) or national, while very few are regional. The circularity goals mainly relate to the Nordic Council of Ministers' focus areas 1, 3, and 4, being 1) carbon neutrality and climate adaptation, 3) sustainable production, and 4) sustainable consumption.

Identifying Nordic policy targets for circular construction has been instrumental in selecting key indicators for circular construction in the Nordics – as accounted for in the next chapter.