This paper explores the environmental impacts of retaining or replacing buildings by extending th... more This paper explores the environmental impacts of retaining or replacing buildings by extending the consequential replacement framework (CRF) for life-cycle assessment (LCA) from individual buildings towards the urban scale. It addresses a gap in previous studies by examining the broader consequences of building-level retention or replacement decisions in the built environment, namely greenhouse gas (GHG) emissions from associated infrastructure construction. The case study, which is located in Finland, investigates alternative ways to densify a growing city, some of which can be achieved within the urban structure, while others require greenfield construction elsewhere in the city. The results reveal that refurbishing and extending already existing buildings is worthwhile in terms of GHG emissions, even if some of the additional floor area targeted in densification were to be built on a greenfield site. After 50 years, the accumulated GHG emissions of scenarios that develop existing buildings are 0.2-12% less than those from replacement scenarios, depending on whether the targeted densification is minor or major and the amount of infrastructure construction involved. This is primarily due to the 11-35% smaller upfront embodied GHG emissions of refurbishment compared with new construction-which 50 years do not offset.
Policy relevance This paper reinforces the notion from previous research that developing the existing building stock holds major emission-savings potential, even more so than replacement with energy-efficient new build. It highlights the potential contribution of existing building stocks in low-emission city development, even in growing city contexts. The case study results challenge the common belief in urban planning that if replacement involves densification, it must be a more low-emission alternative than retention, and conversely, if retention leads to greenfield construction, it must be higher in emissions than replacement. Low-emission urban planning should base its conclusions on urban LCA. This paper introduces an infrastructure-extended CRF that accounts for building retention and replacement scenarios, ensuring methodological robustness. The approach is essential for policymakers to base their decisions on evidence and prioritise low-emission development alternatives. Which policymakers hold power over such decisions and which instruments are suitable to pursue these goals depend on the context.
In the circular economy, building stocks are valuable urban mines of secondary resources and rese... more In the circular economy, building stocks are valuable urban mines of secondary resources and reserves of space whose utilization has the potential to substitute for virgin resources. The purpose of this study is to compare patterns in construction (inflows) and demolition (outflows) and how they shaped the building stock in two Finnish cities, Vantaa and Tampere between 2000 and 2018. By attributing flows to distinct urban development patterns (such as greenfield, replacement, infill, etc.) and investigating population and labour force structure, the goal is to recognize differences and similarities between the case studies. In doing so, the aim is to understand how a comparative approach may help to identify drivers and patterns in the building stock dynamics of the two cities which further aids the development of a circular building stock management. The methodological foundation for this research is Urban Metabolism in form of Material Flow Analysis with a focus on the product i.e., building level but also space as a service provided by buildings. Tampere and Vantaa are the third and fourth largest cities in Finland, with a population of circa 230,000 each. Despite their similar sizes, differences in their geographical properties, contexts, and roles in Finland make them interesting targets for comparative research.
The results show that growth in population and labour force led to a substantial increase in both cities’ building stocks. While Vantaa’s more rural character allowed a higher amount of sprawl by loose-built housing typologies, geographical restrictions and the already dense building stock in Tampere often led to more compact housing and an overall higher amount of demolition in relation to construction. The development of both non-residential building stocks shows a clear tendency towards typologies that support respective economic operations. Alas, material intensity coefficients, which would enable quantifying the material and CO2 impacts of these developments, do not yet exist for Finnish building typologies. Nevertheless, this study’s findings provide a preliminary understanding of how different mechanisms of urban development, such as construction and demolition, shape environmental strains and support the development of pinpoint circular strategies.
Older buildings are often vilified for alleged poor energy performance. This discussion has, howe... more Older buildings are often vilified for alleged poor energy performance. This discussion has, however, been limited to operational energy, rather than whole-life carbon. This paper compares both embodied and operational carbon emissions of building preservation to new construction. Methodologically, it relies on consequential replacement LCA. Using a representative 1950s school building as a case study, a locally heritage-listed example of Modernist architecture, four retention scenarios are devised. The scenarios represent different approaches towards repair needs, cost implications, time horizons of refurbishment, and conserving the building's architectural-historical value. For the contemporary new build, two scenarios are developed based on a case study school building completed in 2018. They differ by the material of the structural frame (concrete or cross-laminated timber). The concrete-framed alternative corresponds to the present business as usual, whereas the wooden alternative represents a competing lower-carbon technology. The study was conducted in Finland, i.e. a cold continental climate. In such conditions, operational energy consumption is significant for a building's carbon footprint. Nevertheless, the findings show that building preservation results in lower emissions than new construction in most of the scenarios. The climate change mitigation potential of building preservation is significant at the scale of singular buildings and the building stock scale.
A simple method is presented to improve the evaluation of past and/or future CO 2 emissions of he... more A simple method is presented to improve the evaluation of past and/or future CO 2 emissions of heating and/or cooling a building. The degree-day-energy emission coefficient (DD-EEC) method relies on two established techniques. It starts with a building's known annual heating and/or cooling energy consumption. Degree-days are employed to estimate the consumption in other years, unveiling how climate warming influences the annual energy need for heating and/or cooling. The resulting emissions are then quantified by associating the energy need in each year with the emission factor for energy production that year. A case study demonstrates an application of the method: a 1950s' school building in Finland. Its past heating-related operational CO 2 emissions are reconstructed from its erection until today, and the future heating and cooling emissions are forecasted until 2100. The case demonstrates the impact of climate warming and projected energy decarbonisation on emissions, showcasing that the past may not be the best future predictor. In the 2010s, the emissions were estimated to be 57% of the 1960s' level. In the 2090s, they could be as little as 5% of the 2010s' level, even though the building's technical properties remain unchanged.
Building component reuse (BCR) is a critical means to reach sustainability goals in the construct... more Building component reuse (BCR) is a critical means to reach sustainability goals in the construction industry through decreasing resource consumption, waste generation, and associated emissions. However, little is known about how BCR in circular construction can create economic value and opportunities for value creation and capture. Therefore, a qualitative multiple case study was conducted of two construction projects in Finland in which precast concrete building components were reused. Extensive datasets, combining interview data, observation, and written materials, were gathered to investigate and compare the projects, examine how economic value can be created from reuse for construction value chain actors, and identify the factors that determine value capture potential. The findings show that BCR may create economic value by decreasing costs and material consumption, but also by increasing material performance and creating new circular business models and revenue sources (such as concrete refurbishment and reuse-oriented design). Twenty-one value capture determinants for BCR were identified and classified into five value clusters on the micro, meso, and macro levels. The study expands circular construction research by associating circular value potential with the feasibility aspects of reuse in construction, giving businesses invaluable insights on how to gain economic benefits from concrete BCR.
The Routledge Handbook of Catalysts for a Sustainable Circular Economy, 2023
Construction is one of the most significant sectors consuming virgin materials and producing wast... more Construction is one of the most significant sectors consuming virgin materials and producing waste and greenhouse gases. The circular economy has been proposed as a solution to the industry's environmental problems. However, the transition has proved difficult and biased towards recycling rather than waste prevention and reuse. It is not known how the industry could adopt reuse-based solutions, even if reuse could reduce the environmental burdens more so than recycling. This chapter provides insights into how the construction sector could become more circular and low-carbon by reusing building components. It stems from developing the ReCreate project (Horizon 2020), which investigates the deconstruction and reuse of prefabricated concrete elements not originally designed for disassembly. The analytical approach used here is Frank Geels's multi-level perspective for technology transitions. This chapter is a theoretical contribution that identifies and explains a wide spectrum of diverse catalysts necessary for the reuse transition, ranging from technological development (in deconstruction, remanufacturing, design, and digitalisation) to societal and economic developments (in behaviour and acceptance, work skills, safety, regulation, business models, and value chains). It also discusses catalysts' roles and timeframes in the nexus of a sociotechnical regime (business-as-usual construction) and niche innovation (reuse), which is attempting a breakthrough. A conceptual framework is provided for facilitating a reuse transition in the construction sector.
This special issue explores when, why and how demolition occurs with the aim to understand its en... more This special issue explores when, why and how demolition occurs with the aim to understand its environmental, socioeconomic and cultural drivers, and consequences in policy and practice alike. Based on previous research, demolition is known to have many adverse effects. The potential for avoiding building replacement (demolition and subsequent new build) and favouring retention is also in this special issue's interest. The papers in the issue contribute insights from different scales, from the level of a building to that of a city. As a whole, the articles touch upon all types of impacts, i.e. environmental, economic and socio-cultural aspects. Eight case studies from various contexts, mainly Europe, but also the US and Australia, contribute novel methods, findings and policy insights. This editorial sets the need and background for research into demolition, classifies the included papers to three categories, explains their contributions to research and practice, and outlines outstanding research gaps and agenda for further research. The papers are categorised as: (1) drivers and policies on demolition versus retention; (2) environmental and social impact assessment at building level; and (3) practical demolition decision-making. The contributions suggest, among other findings, positive environmental impacts from building retention as opposed to demolition, and discuss how policy designs from the city to the building level can either encourage or discourage retention. Due to its implications, many of which remain understudied, demolition and its alternatives should gain importance on research, design, planning, construction and real estate agendas in the years to come.
This dataset contains the material volumes, masses, and intensities for a total of 45 residential... more This dataset contains the material volumes, masses, and intensities for a total of 45 residential building cohorts in Finland from the 1940s to the 2010s. The specific building types included are one dwelling houses and blocks of flats. The data were drawn from representative case buildings and their derivatives. The data are primarily based on construction drawings, complemented by other documents such as bills of materials. The source material was mainly obtained from the archives of the building inspection authority of the city of Vantaa, Finland. Material volumes were derived from the construction drawings either directly from annotations or, when needed, by further measurements made based on the same material. For minor lacks of information in the original documents, documents of similar buildings and literature were consulted. A total of 26 buildings were inventoried directly. For each included combination of building type, construction decade, and bearing material these were the ones with the most common façade material. In addition, 19 buildings with the second most common façade material were formed based on these to represent the 45 cohorts. Material masses, and by extension intensities, were calculated based on the recorded volumes and typical densities of construction materials used in Finland. The material volumes, masses, and intensities per material and in total are presented as three spreadsheet tables, along with a description sheet, on three corresponding hierarchical levels of aggregation: per representative building, per vertical building level (foundations, basement, first storey, etc.), and per building part (floor, exterior walls, interior walls, etc.). Furthermore, they are distinguished between the building structure and complementary building components (windows and doors). The data can be used in academic, policy related, and practical investigations of the building stock, such as in evaluating the material consumption consequences of different spatial planning strategies on various levels or estimating the materials embedded in the built environment and their potential for capitalisation in the circular economy.
Is it more environmentally friendly to replace an existing building with a new one or to renovate... more Is it more environmentally friendly to replace an existing building with a new one or to renovate the existing property? This paper addresses how to frame and evaluate this question. Although several previous studies exist, their methods lack a harmonised set of practice. A new framework is introduced that adopts the concept of consequential replacement framework (CRF) for life cycle assessment (LCA) which had previously been applied to vehicles. The application of the CRF to buildings is demonstrated with case studies on school buildings in Finland. Three alternative cases are examined: the refurbishment of a 1950s school; extending it with an annex; and demolition and replacement with a new concrete or timber building. As the European environmental impact regulation of buildings pertains to CO2 emissions, the paper also focuses on CO2. The case studies demonstrate that refurbishment in Finland is a more climate-friendly alternative to demolition and new build. The studied new buildings’ better energy efficiency is set off for decades by the carbon spike caused by the embodied CO2 in their materials. The CRF is shown to be a methodologically sound, easily approachable framework for evaluating immediate environmental consequences of decision-makers’ retention or replacement choices, suitable to different contexts.
Policy relevance As the global CO2 budget is running out, the need to combat the escalation of the climate emergency is imminent. Decades-long payback times for embodied CO2 investments in new replacement buildings, as in the paper’s case studies, are not helpful in this effort. The introduced framework helps to uncover the climate change mitigation potential in building preservation, which is presently poorly understood and considered in policymaking. The new framework provides a useful decision support tool and evidence for both policymakers and planners. Current policy initiatives in Europe focus on CO2 regulation for new build and renovation. However, replacement situations are not yet regulated. In contexts where renovation clearly proves to be more climate friendly (as validated by this method), policymakers should recognise the greenhouse gas-mitigation potential in building retention and create policies to encourage renovation over new build.
Environment and Planning B: Urban Analytics and City Science, 2022
Anthropogenic stocks are increasingly seen as potential reserves for secondary resources, which h... more Anthropogenic stocks are increasingly seen as potential reserves for secondary resources, which has led to a rapid development in research of urban metabolic systems. With regard to buildings and their associated material stocks and flows, one of the most critical shortcomings in the state-of-theart is the knowledge gap for drivers, dynamics, patterns and linkages that affect the urban metabolism. This paper is premised on the idea that urban planning stirs up these material flows, so it should also adopt their sustainable management on its agenda. It presents an approach that highlights the intertwined nature of changing urban morphology and building material stocks and flows in space and time. An analytical framework, based on the principles of material flow analysis, is provided for an integrated, spatiotemporal study of urban morphology and urban metabolism of buildings, using building and plot data as the input and identifying internal processes of the urban metabolism as the output. The identified processes include greenfield development, infill construction, building replacement and shrinkage, each of which can be expected to have tangible yet very different material and environmental consequences in the form of embodied materials and CO2. The use of the framework is demonstrated with a case study in the Finnish city of Vantaa in 2000-2018. The case study shows patterns pertaining to a growing city unrestricted by geographic or historic factors, manifested as vast greenfield developments and replacement of a notably young building stock. As sustainability may soon call into question both these strategies, uncovering the material consequences of a city's past urban (re)development strategies lay the foundation for using the presented approach proactively in planning support, in pursuit of more circular economy-based and low carbon cities.
Reusing deconstructed materials and components can help to decrease the environmental burden of b... more Reusing deconstructed materials and components can help to decrease the environmental burden of buildings. To safely reuse reclaimed items in new construction, methods are needed to reliably identify the essential technical properties of the deconstructed products. This paper looks at salvaged bricks and examines different indirect test methods to assess their properties. The explored test methods include visual observation, pitch of a sound, ultrasonic pulse velocity (UPV), and thin section. Reclaimed clay bricks and calcium silicate bricks were used in the research. They originated from four different buildings and from different kinds of structures. New bricks of the same kinds were also tested for reference and the properties were compared to the reclaimed ones. The assessed properties entail initial rate of water absorption, water absorption capacity, compressive strength, and freeze-thaw durability. The results show that it is possible to assess the deviation of properties and sort out exceptional bricks from a series with visual observation and pitch of a sound. The deviation of different properties can also be assessed with the help of UPV. A correlation was found between UPV and water absorption, compressive strength and freeze-thaw durability. Lower UPV values mean higher water absorption capacity and vice versa. Compressive strength of bricks is clearly lower when the UPV value is low and higher when the UPV is high. Bricks with lower UPV values (< 1.5 km/s) were also found to be freeze-thaw durable while those with higher UPV values (> 3.0 km/s) were found to be nondurable. Between the mentioned two values, the freeze-thaw durability varied. Thin section was only used to assess freeze-thaw durability and it was found to be unreliable as a method.
Housing adaptability is often said to be a characteristic that benefits the residents. But is the... more Housing adaptability is often said to be a characteristic that benefits the residents. But is there an actual demand from residents? This study asks whether and what kind of value residents place on adaptable housing. The research, situated in Finland, combines interviews involving seven varied households together with their experiences of adaptable flats in a 3D CAVE immersive virtual reality environment. The participants were first interviewed about their current life, housing situations and expected future changes in household composition or housing needs. For the virtual viewings, flats with systematically transformable floor plans were designed to anticipate situations that could occur during people’s housing careers (e.g. the birth of a child, working from home, a child leaving home, additional healthcare, e.g.). The participants walked through virtual flats selected for them based on the first interview. Afterwards, they were re-interviewed, focusing on the value they place on the presented adaptability. All households identified functional benefits for their current or anticipated situation, and many expressed a willingness to buy a home with the demonstrated adaptability characteristics. Most also described economic security that adaptability provides (e.g. renting or selling a part of the flat separately) and the benefits of remaining long term in a flat.
Practice relevance In the adaptability discourse, residents’ opinions have been heard to a very limited degree. More typically, adaptability researchers or architects make the case for adaptability on the residents’ behalf. According to recent research, some architects assume developers are disinterested in building more adaptable flats partly because no real market demand by inhabitants is believed to exist. The findings of the current study demonstrate that residents need to be properly informed about the benefits of adaptability by the housing provider. Virtual reality can be a useful tool for demonstrating adaptability characteristics. When sufficiently informed, the participants of the current study considered adaptability as functionally beneficial for the family and a desirable feature that would increase their willingness to buy and pay a premium. To demonstrate a potential market or its absence in a given context, residents’ views should be sought more widely and more often.
Journal of Housing and the Built Environment, 2021
Adaptability is one key aspect in making housing more sustainable. One major approach to adaptabi... more Adaptability is one key aspect in making housing more sustainable. One major approach to adaptability is internal transformability of buildings, i.e. the possibility to make modifications to the spaces and their equipment within the existing building envelope. This aspect is often taken into consideration in the design and implementation of office buildings. However, in housing the situation is different, and internal transformability is very seldom implemented in apartment buildings. There is a lack of studies for the reasons for this. In this article we take a look at the barriers to internal transformability of apartment buildings in two Nordic countries, Finland and Denmark. We compare the situations in both countries, and highlight their similarities and differences. The research is based on interviews of Finnish and Danish architects who have been involved in designing such buildings within the last 20 years. The interviews show that the disinterest of housing developers has been the main barrier to implementing internal transformability. Another important barrier is the developers' cost-optimization. Secondary barriers were related to lack of solutions in building services that would support internal transformability. Additionally, secondary barriers were related to common construction techniques, regulations, and building conventions. Major barriers were similar in both countries. However, some differences in the secondary and other barriers between the two countries also exist.
Research has identified cities as potential urban mines for recovering secondary construction mat... more Research has identified cities as potential urban mines for recovering secondary construction materials. Studies typically focus on stocks or flows of bulk materials on high abstraction levels. To enable a shift of focus towards higher levels of circular economy, such as waste minimization, there is a need for a more detailed understanding of the dynamics that contribute to the waste flows, building replacement in particular. This paper examines the characteristics and location of the stocks and flows of buildings in the city of Tampere, Finland, over the last 20 years. Statistical and geographical analyses are performed on the building stock, new construction and demolition in Tampere to unveil patterns pertaining to stock change and building replacement. The study shows that these patterns vary significantly between buildings of different function. Spatially confined redevelopment areas within the city structure, i.e. brownfields and greyfields, whose industrial and commercial functions yield to housing and mixed residential-commercial use, make up major arenas for replacement. Policy-making should acknowledge that urban planning stirs these waste flows and incorporate their conscious prevention and management on its agenda.
Art historian Juan Pablo Bonta has presented a nine-step model for analysing how the interpretati... more Art historian Juan Pablo Bonta has presented a nine-step model for analysing how the interpretation of architectural oeuvres becomes canonised. We suggest that in terms of the built heritage, canonisation and heritagisation are essentially the same process, so Bonta’s model can be used for analysing heritagisation processes. This article testifies to this assumption by examining how the interpretation of historic Nordic wooden towns became stabilised in Finland. The concept was introduced in the 1960s to describe the Nordic urban heritage that was threatened by massive town development projects. The identification of the heritage category enabled the preservation of some remaining wooden districts. Examining this process allows us to discuss the role of expertise in the building preservation. In the case of wooden towns, experts’ early recognition was a crucial precondition for the preservation of the heritage, which enabled novel generations to form a living relationship with it. Seen through the experts’ writings, the heritagisation process of the wooden towns also reflect the expanding scope of the built heritage discipline. Based on our findings, the canonisation model is applicable not only to the individual oevres, as Bonta addresses, but also to broader built environments and, more conceptually, to heritage categories.
International Journal of Building Pathology and Adaptation, 2020
Purpose - Ageing populations induce needs to adapt existing housing. With ageing, the number of f... more Purpose - Ageing populations induce needs to adapt existing housing. With ageing, the number of frail old people, who require assistance in daily life, is also increased. Converting existing housing into assisted living enables them to remain in their community while receiving necessary support and care. The purpose is to investigate whether postwar mass housing is spatially appropriate for adaptation into group homes for older people.
Design/methodology/approach - The research material is attained from Finland. Spatial requirements for group homes are drawn from 130 units built or renovated during 2000-2015. Spatial characteristics of mass housing are mapped from 105 apartment buildings built in the 1970s. The latter are matched with the former by comparing the connectivity of layouts, sizes of units and the numbers and sizes of individual spaces.
Findings - Group homes typically utilize a linear layout, which can easily be created in apartment buildings. Individual spaces of a group home fit apartment buildings effortlessly. Whole group home units mostly prove to be spatially feasible but result in looser dimensioning than is typical in existing units. The mass housing stock can be considered a spatial reserve for adaptation into group homes.
Originality/value - This is the first study to employ a large-scale, multi-case spatial mapping approach to analyse the adaptability properties of mass housing into assisted living. The findings pertain primarily to the Finnish context, but a methodology is presented which can be applied to other countries and also to other spatial functions.
Journal of Cultural Heritage Management and Sustainable Development, 2019
Purpose
The purpose of this paper is to discuss the relation between building conservation and c... more Purpose
The purpose of this paper is to discuss the relation between building conservation and circular economy (CE), which are often erroneously seen as inherently contradictory to one another.
Design/methodology/approach
The work draws from a comparative approach. The paper reviews a body of literature on architectural conservation and CE to establish an understanding on the state-of-the-art for both disciplines separately. Then, the relation between thereof is developed through a theoretical discourse.
Findings
Both architectural conservation and CE aim at safeguarding value, although they define “value” differently. Fabric-focused conservation and CE favor minimal intervention to material, albeit they arrive at this conclusion from different bases. Consequently, both approaches struggle with the low cost of virgin resource extraction and waste production and the high cost of human labor in contemporary Western societies. CE could be harnessed for building conservation by adopting its vocabulary and methodology, such as lifecycle assessment and material flow analysis. Transitioning toward CE can help increase the preservation of built heritage while redefining what is meant by “heritage” and “waste.”
Originality/value
Prior to this paper, there have been no articles addressing the relationship of the concepts explicitly and to this extent. The paper provides a theoretical basis for further discourse and outlines some implications of CE for the construction and built heritage disciplines.
Art historian Juan Pablo Bonta has presented a nine-step model for analysing how the interpretati... more Art historian Juan Pablo Bonta has presented a nine-step model for analysing how the interpretation of architectural oeuvres becomes canonised. We suggest that in terms of the built heritage, canonisation and heritagisation are essentially the same process, so Bonta’s model can be used for analysing heritagisation processes. This article testifies to this assumption by examining how the interpretation of historic Nordic wooden towns became stabilised in Finland. The concept was introduced in the 1960s to describe the Nordic urban heritage that was threatened by massive town development projects. The identification of the heritage category enabled the preservation of some remaining wooden districts. Examining this process allows us to discuss the role of expertise in the building preservation. In the case of wooden towns, experts’ early recognition was a crucial precondition for the preservation of the heritage, which enabled novel generations to form a living relationship with it. Seen through the experts’ writings, the heritagisation process of the wooden towns also reflect the expanding scope of the built heritage discipline. Based on our findings, the canonisation model is applicable not only to the individual oevres, as Bonta addresses, but also to broader built environments and, more conceptually, to heritage categories.
In Western Europe, many large housing estates have experienced spirals of intertwined physical an... more In Western Europe, many large housing estates have experienced spirals of intertwined physical and social decline. Such estates have wound up at the bottom of the housing hierarchy, which is manifested as high turnovers and vacancies. This qualitative multi-case study contributes to the research on the sustainable management of declining neighbourhoods’ housing stocks. The study learns from four individual cases in which vacancies were tackled with an extreme architectural transformation. In the investigated cases, large-panel buildings were partially deconstructed and renovated, and the reclaimed concrete panels were reused for new construction nearby. The approach integrates demolition, renovation and new construction − the three characteristic building stock management strategies in disadvantaged neighbourhoods. The cases are located in Sweden (Gothenburg, 1984), the Netherlands (Middelburg, 1986), Germany (Berlin, 2004) and Finland (Raahe, 2010). Deconstruction was the landlords’ way to manage their assets in the face of vacancies and social problems in relatively young, unamortized buildings. The projects proved technically feasible, yet they have been criticised for their economic and social implications. Nonetheless, the approach seems to have contributed to extending the life cycles of the buildings in question, and it has the potential to improve the quality of life in large housing estates.
In the fields of archaeology, art history and history, spolia have traditionally been studied as ... more In the fields of archaeology, art history and history, spolia have traditionally been studied as phenomena of the past. Today, the reuse of salvaged construction components and materials is primarily justified by its economic and ecological benefits, while its architectural and experiential qualities are much less discussed, if at all. Therefore, this article has two focuses, one more conceptual, and the other, more practical. Firstly, the article suggests extending the concept of spolia to contemporary architecture and discusses the usefulness of the concept in evaluating experiential values in contemporary constructions that make use of reclaimed parts. Secondly, it evaluates the potential of spoliation as a modern design tool in search of a more complex and historicity-based architectural expression. This potential is examined by defining the requirements for the extended concept and through analyzing examples of contemporary design. Although the main focus of this article is on contemporary architecture based on old building components, the topic also has obvious implications for heritage management.
This paper explores the environmental impacts of retaining or replacing buildings by extending th... more This paper explores the environmental impacts of retaining or replacing buildings by extending the consequential replacement framework (CRF) for life-cycle assessment (LCA) from individual buildings towards the urban scale. It addresses a gap in previous studies by examining the broader consequences of building-level retention or replacement decisions in the built environment, namely greenhouse gas (GHG) emissions from associated infrastructure construction. The case study, which is located in Finland, investigates alternative ways to densify a growing city, some of which can be achieved within the urban structure, while others require greenfield construction elsewhere in the city. The results reveal that refurbishing and extending already existing buildings is worthwhile in terms of GHG emissions, even if some of the additional floor area targeted in densification were to be built on a greenfield site. After 50 years, the accumulated GHG emissions of scenarios that develop existing buildings are 0.2-12% less than those from replacement scenarios, depending on whether the targeted densification is minor or major and the amount of infrastructure construction involved. This is primarily due to the 11-35% smaller upfront embodied GHG emissions of refurbishment compared with new construction-which 50 years do not offset.
Policy relevance This paper reinforces the notion from previous research that developing the existing building stock holds major emission-savings potential, even more so than replacement with energy-efficient new build. It highlights the potential contribution of existing building stocks in low-emission city development, even in growing city contexts. The case study results challenge the common belief in urban planning that if replacement involves densification, it must be a more low-emission alternative than retention, and conversely, if retention leads to greenfield construction, it must be higher in emissions than replacement. Low-emission urban planning should base its conclusions on urban LCA. This paper introduces an infrastructure-extended CRF that accounts for building retention and replacement scenarios, ensuring methodological robustness. The approach is essential for policymakers to base their decisions on evidence and prioritise low-emission development alternatives. Which policymakers hold power over such decisions and which instruments are suitable to pursue these goals depend on the context.
In the circular economy, building stocks are valuable urban mines of secondary resources and rese... more In the circular economy, building stocks are valuable urban mines of secondary resources and reserves of space whose utilization has the potential to substitute for virgin resources. The purpose of this study is to compare patterns in construction (inflows) and demolition (outflows) and how they shaped the building stock in two Finnish cities, Vantaa and Tampere between 2000 and 2018. By attributing flows to distinct urban development patterns (such as greenfield, replacement, infill, etc.) and investigating population and labour force structure, the goal is to recognize differences and similarities between the case studies. In doing so, the aim is to understand how a comparative approach may help to identify drivers and patterns in the building stock dynamics of the two cities which further aids the development of a circular building stock management. The methodological foundation for this research is Urban Metabolism in form of Material Flow Analysis with a focus on the product i.e., building level but also space as a service provided by buildings. Tampere and Vantaa are the third and fourth largest cities in Finland, with a population of circa 230,000 each. Despite their similar sizes, differences in their geographical properties, contexts, and roles in Finland make them interesting targets for comparative research.
The results show that growth in population and labour force led to a substantial increase in both cities’ building stocks. While Vantaa’s more rural character allowed a higher amount of sprawl by loose-built housing typologies, geographical restrictions and the already dense building stock in Tampere often led to more compact housing and an overall higher amount of demolition in relation to construction. The development of both non-residential building stocks shows a clear tendency towards typologies that support respective economic operations. Alas, material intensity coefficients, which would enable quantifying the material and CO2 impacts of these developments, do not yet exist for Finnish building typologies. Nevertheless, this study’s findings provide a preliminary understanding of how different mechanisms of urban development, such as construction and demolition, shape environmental strains and support the development of pinpoint circular strategies.
Older buildings are often vilified for alleged poor energy performance. This discussion has, howe... more Older buildings are often vilified for alleged poor energy performance. This discussion has, however, been limited to operational energy, rather than whole-life carbon. This paper compares both embodied and operational carbon emissions of building preservation to new construction. Methodologically, it relies on consequential replacement LCA. Using a representative 1950s school building as a case study, a locally heritage-listed example of Modernist architecture, four retention scenarios are devised. The scenarios represent different approaches towards repair needs, cost implications, time horizons of refurbishment, and conserving the building's architectural-historical value. For the contemporary new build, two scenarios are developed based on a case study school building completed in 2018. They differ by the material of the structural frame (concrete or cross-laminated timber). The concrete-framed alternative corresponds to the present business as usual, whereas the wooden alternative represents a competing lower-carbon technology. The study was conducted in Finland, i.e. a cold continental climate. In such conditions, operational energy consumption is significant for a building's carbon footprint. Nevertheless, the findings show that building preservation results in lower emissions than new construction in most of the scenarios. The climate change mitigation potential of building preservation is significant at the scale of singular buildings and the building stock scale.
A simple method is presented to improve the evaluation of past and/or future CO 2 emissions of he... more A simple method is presented to improve the evaluation of past and/or future CO 2 emissions of heating and/or cooling a building. The degree-day-energy emission coefficient (DD-EEC) method relies on two established techniques. It starts with a building's known annual heating and/or cooling energy consumption. Degree-days are employed to estimate the consumption in other years, unveiling how climate warming influences the annual energy need for heating and/or cooling. The resulting emissions are then quantified by associating the energy need in each year with the emission factor for energy production that year. A case study demonstrates an application of the method: a 1950s' school building in Finland. Its past heating-related operational CO 2 emissions are reconstructed from its erection until today, and the future heating and cooling emissions are forecasted until 2100. The case demonstrates the impact of climate warming and projected energy decarbonisation on emissions, showcasing that the past may not be the best future predictor. In the 2010s, the emissions were estimated to be 57% of the 1960s' level. In the 2090s, they could be as little as 5% of the 2010s' level, even though the building's technical properties remain unchanged.
Building component reuse (BCR) is a critical means to reach sustainability goals in the construct... more Building component reuse (BCR) is a critical means to reach sustainability goals in the construction industry through decreasing resource consumption, waste generation, and associated emissions. However, little is known about how BCR in circular construction can create economic value and opportunities for value creation and capture. Therefore, a qualitative multiple case study was conducted of two construction projects in Finland in which precast concrete building components were reused. Extensive datasets, combining interview data, observation, and written materials, were gathered to investigate and compare the projects, examine how economic value can be created from reuse for construction value chain actors, and identify the factors that determine value capture potential. The findings show that BCR may create economic value by decreasing costs and material consumption, but also by increasing material performance and creating new circular business models and revenue sources (such as concrete refurbishment and reuse-oriented design). Twenty-one value capture determinants for BCR were identified and classified into five value clusters on the micro, meso, and macro levels. The study expands circular construction research by associating circular value potential with the feasibility aspects of reuse in construction, giving businesses invaluable insights on how to gain economic benefits from concrete BCR.
The Routledge Handbook of Catalysts for a Sustainable Circular Economy, 2023
Construction is one of the most significant sectors consuming virgin materials and producing wast... more Construction is one of the most significant sectors consuming virgin materials and producing waste and greenhouse gases. The circular economy has been proposed as a solution to the industry's environmental problems. However, the transition has proved difficult and biased towards recycling rather than waste prevention and reuse. It is not known how the industry could adopt reuse-based solutions, even if reuse could reduce the environmental burdens more so than recycling. This chapter provides insights into how the construction sector could become more circular and low-carbon by reusing building components. It stems from developing the ReCreate project (Horizon 2020), which investigates the deconstruction and reuse of prefabricated concrete elements not originally designed for disassembly. The analytical approach used here is Frank Geels's multi-level perspective for technology transitions. This chapter is a theoretical contribution that identifies and explains a wide spectrum of diverse catalysts necessary for the reuse transition, ranging from technological development (in deconstruction, remanufacturing, design, and digitalisation) to societal and economic developments (in behaviour and acceptance, work skills, safety, regulation, business models, and value chains). It also discusses catalysts' roles and timeframes in the nexus of a sociotechnical regime (business-as-usual construction) and niche innovation (reuse), which is attempting a breakthrough. A conceptual framework is provided for facilitating a reuse transition in the construction sector.
This special issue explores when, why and how demolition occurs with the aim to understand its en... more This special issue explores when, why and how demolition occurs with the aim to understand its environmental, socioeconomic and cultural drivers, and consequences in policy and practice alike. Based on previous research, demolition is known to have many adverse effects. The potential for avoiding building replacement (demolition and subsequent new build) and favouring retention is also in this special issue's interest. The papers in the issue contribute insights from different scales, from the level of a building to that of a city. As a whole, the articles touch upon all types of impacts, i.e. environmental, economic and socio-cultural aspects. Eight case studies from various contexts, mainly Europe, but also the US and Australia, contribute novel methods, findings and policy insights. This editorial sets the need and background for research into demolition, classifies the included papers to three categories, explains their contributions to research and practice, and outlines outstanding research gaps and agenda for further research. The papers are categorised as: (1) drivers and policies on demolition versus retention; (2) environmental and social impact assessment at building level; and (3) practical demolition decision-making. The contributions suggest, among other findings, positive environmental impacts from building retention as opposed to demolition, and discuss how policy designs from the city to the building level can either encourage or discourage retention. Due to its implications, many of which remain understudied, demolition and its alternatives should gain importance on research, design, planning, construction and real estate agendas in the years to come.
This dataset contains the material volumes, masses, and intensities for a total of 45 residential... more This dataset contains the material volumes, masses, and intensities for a total of 45 residential building cohorts in Finland from the 1940s to the 2010s. The specific building types included are one dwelling houses and blocks of flats. The data were drawn from representative case buildings and their derivatives. The data are primarily based on construction drawings, complemented by other documents such as bills of materials. The source material was mainly obtained from the archives of the building inspection authority of the city of Vantaa, Finland. Material volumes were derived from the construction drawings either directly from annotations or, when needed, by further measurements made based on the same material. For minor lacks of information in the original documents, documents of similar buildings and literature were consulted. A total of 26 buildings were inventoried directly. For each included combination of building type, construction decade, and bearing material these were the ones with the most common façade material. In addition, 19 buildings with the second most common façade material were formed based on these to represent the 45 cohorts. Material masses, and by extension intensities, were calculated based on the recorded volumes and typical densities of construction materials used in Finland. The material volumes, masses, and intensities per material and in total are presented as three spreadsheet tables, along with a description sheet, on three corresponding hierarchical levels of aggregation: per representative building, per vertical building level (foundations, basement, first storey, etc.), and per building part (floor, exterior walls, interior walls, etc.). Furthermore, they are distinguished between the building structure and complementary building components (windows and doors). The data can be used in academic, policy related, and practical investigations of the building stock, such as in evaluating the material consumption consequences of different spatial planning strategies on various levels or estimating the materials embedded in the built environment and their potential for capitalisation in the circular economy.
Is it more environmentally friendly to replace an existing building with a new one or to renovate... more Is it more environmentally friendly to replace an existing building with a new one or to renovate the existing property? This paper addresses how to frame and evaluate this question. Although several previous studies exist, their methods lack a harmonised set of practice. A new framework is introduced that adopts the concept of consequential replacement framework (CRF) for life cycle assessment (LCA) which had previously been applied to vehicles. The application of the CRF to buildings is demonstrated with case studies on school buildings in Finland. Three alternative cases are examined: the refurbishment of a 1950s school; extending it with an annex; and demolition and replacement with a new concrete or timber building. As the European environmental impact regulation of buildings pertains to CO2 emissions, the paper also focuses on CO2. The case studies demonstrate that refurbishment in Finland is a more climate-friendly alternative to demolition and new build. The studied new buildings’ better energy efficiency is set off for decades by the carbon spike caused by the embodied CO2 in their materials. The CRF is shown to be a methodologically sound, easily approachable framework for evaluating immediate environmental consequences of decision-makers’ retention or replacement choices, suitable to different contexts.
Policy relevance As the global CO2 budget is running out, the need to combat the escalation of the climate emergency is imminent. Decades-long payback times for embodied CO2 investments in new replacement buildings, as in the paper’s case studies, are not helpful in this effort. The introduced framework helps to uncover the climate change mitigation potential in building preservation, which is presently poorly understood and considered in policymaking. The new framework provides a useful decision support tool and evidence for both policymakers and planners. Current policy initiatives in Europe focus on CO2 regulation for new build and renovation. However, replacement situations are not yet regulated. In contexts where renovation clearly proves to be more climate friendly (as validated by this method), policymakers should recognise the greenhouse gas-mitigation potential in building retention and create policies to encourage renovation over new build.
Environment and Planning B: Urban Analytics and City Science, 2022
Anthropogenic stocks are increasingly seen as potential reserves for secondary resources, which h... more Anthropogenic stocks are increasingly seen as potential reserves for secondary resources, which has led to a rapid development in research of urban metabolic systems. With regard to buildings and their associated material stocks and flows, one of the most critical shortcomings in the state-of-theart is the knowledge gap for drivers, dynamics, patterns and linkages that affect the urban metabolism. This paper is premised on the idea that urban planning stirs up these material flows, so it should also adopt their sustainable management on its agenda. It presents an approach that highlights the intertwined nature of changing urban morphology and building material stocks and flows in space and time. An analytical framework, based on the principles of material flow analysis, is provided for an integrated, spatiotemporal study of urban morphology and urban metabolism of buildings, using building and plot data as the input and identifying internal processes of the urban metabolism as the output. The identified processes include greenfield development, infill construction, building replacement and shrinkage, each of which can be expected to have tangible yet very different material and environmental consequences in the form of embodied materials and CO2. The use of the framework is demonstrated with a case study in the Finnish city of Vantaa in 2000-2018. The case study shows patterns pertaining to a growing city unrestricted by geographic or historic factors, manifested as vast greenfield developments and replacement of a notably young building stock. As sustainability may soon call into question both these strategies, uncovering the material consequences of a city's past urban (re)development strategies lay the foundation for using the presented approach proactively in planning support, in pursuit of more circular economy-based and low carbon cities.
Reusing deconstructed materials and components can help to decrease the environmental burden of b... more Reusing deconstructed materials and components can help to decrease the environmental burden of buildings. To safely reuse reclaimed items in new construction, methods are needed to reliably identify the essential technical properties of the deconstructed products. This paper looks at salvaged bricks and examines different indirect test methods to assess their properties. The explored test methods include visual observation, pitch of a sound, ultrasonic pulse velocity (UPV), and thin section. Reclaimed clay bricks and calcium silicate bricks were used in the research. They originated from four different buildings and from different kinds of structures. New bricks of the same kinds were also tested for reference and the properties were compared to the reclaimed ones. The assessed properties entail initial rate of water absorption, water absorption capacity, compressive strength, and freeze-thaw durability. The results show that it is possible to assess the deviation of properties and sort out exceptional bricks from a series with visual observation and pitch of a sound. The deviation of different properties can also be assessed with the help of UPV. A correlation was found between UPV and water absorption, compressive strength and freeze-thaw durability. Lower UPV values mean higher water absorption capacity and vice versa. Compressive strength of bricks is clearly lower when the UPV value is low and higher when the UPV is high. Bricks with lower UPV values (< 1.5 km/s) were also found to be freeze-thaw durable while those with higher UPV values (> 3.0 km/s) were found to be nondurable. Between the mentioned two values, the freeze-thaw durability varied. Thin section was only used to assess freeze-thaw durability and it was found to be unreliable as a method.
Housing adaptability is often said to be a characteristic that benefits the residents. But is the... more Housing adaptability is often said to be a characteristic that benefits the residents. But is there an actual demand from residents? This study asks whether and what kind of value residents place on adaptable housing. The research, situated in Finland, combines interviews involving seven varied households together with their experiences of adaptable flats in a 3D CAVE immersive virtual reality environment. The participants were first interviewed about their current life, housing situations and expected future changes in household composition or housing needs. For the virtual viewings, flats with systematically transformable floor plans were designed to anticipate situations that could occur during people’s housing careers (e.g. the birth of a child, working from home, a child leaving home, additional healthcare, e.g.). The participants walked through virtual flats selected for them based on the first interview. Afterwards, they were re-interviewed, focusing on the value they place on the presented adaptability. All households identified functional benefits for their current or anticipated situation, and many expressed a willingness to buy a home with the demonstrated adaptability characteristics. Most also described economic security that adaptability provides (e.g. renting or selling a part of the flat separately) and the benefits of remaining long term in a flat.
Practice relevance In the adaptability discourse, residents’ opinions have been heard to a very limited degree. More typically, adaptability researchers or architects make the case for adaptability on the residents’ behalf. According to recent research, some architects assume developers are disinterested in building more adaptable flats partly because no real market demand by inhabitants is believed to exist. The findings of the current study demonstrate that residents need to be properly informed about the benefits of adaptability by the housing provider. Virtual reality can be a useful tool for demonstrating adaptability characteristics. When sufficiently informed, the participants of the current study considered adaptability as functionally beneficial for the family and a desirable feature that would increase their willingness to buy and pay a premium. To demonstrate a potential market or its absence in a given context, residents’ views should be sought more widely and more often.
Journal of Housing and the Built Environment, 2021
Adaptability is one key aspect in making housing more sustainable. One major approach to adaptabi... more Adaptability is one key aspect in making housing more sustainable. One major approach to adaptability is internal transformability of buildings, i.e. the possibility to make modifications to the spaces and their equipment within the existing building envelope. This aspect is often taken into consideration in the design and implementation of office buildings. However, in housing the situation is different, and internal transformability is very seldom implemented in apartment buildings. There is a lack of studies for the reasons for this. In this article we take a look at the barriers to internal transformability of apartment buildings in two Nordic countries, Finland and Denmark. We compare the situations in both countries, and highlight their similarities and differences. The research is based on interviews of Finnish and Danish architects who have been involved in designing such buildings within the last 20 years. The interviews show that the disinterest of housing developers has been the main barrier to implementing internal transformability. Another important barrier is the developers' cost-optimization. Secondary barriers were related to lack of solutions in building services that would support internal transformability. Additionally, secondary barriers were related to common construction techniques, regulations, and building conventions. Major barriers were similar in both countries. However, some differences in the secondary and other barriers between the two countries also exist.
Research has identified cities as potential urban mines for recovering secondary construction mat... more Research has identified cities as potential urban mines for recovering secondary construction materials. Studies typically focus on stocks or flows of bulk materials on high abstraction levels. To enable a shift of focus towards higher levels of circular economy, such as waste minimization, there is a need for a more detailed understanding of the dynamics that contribute to the waste flows, building replacement in particular. This paper examines the characteristics and location of the stocks and flows of buildings in the city of Tampere, Finland, over the last 20 years. Statistical and geographical analyses are performed on the building stock, new construction and demolition in Tampere to unveil patterns pertaining to stock change and building replacement. The study shows that these patterns vary significantly between buildings of different function. Spatially confined redevelopment areas within the city structure, i.e. brownfields and greyfields, whose industrial and commercial functions yield to housing and mixed residential-commercial use, make up major arenas for replacement. Policy-making should acknowledge that urban planning stirs these waste flows and incorporate their conscious prevention and management on its agenda.
Art historian Juan Pablo Bonta has presented a nine-step model for analysing how the interpretati... more Art historian Juan Pablo Bonta has presented a nine-step model for analysing how the interpretation of architectural oeuvres becomes canonised. We suggest that in terms of the built heritage, canonisation and heritagisation are essentially the same process, so Bonta’s model can be used for analysing heritagisation processes. This article testifies to this assumption by examining how the interpretation of historic Nordic wooden towns became stabilised in Finland. The concept was introduced in the 1960s to describe the Nordic urban heritage that was threatened by massive town development projects. The identification of the heritage category enabled the preservation of some remaining wooden districts. Examining this process allows us to discuss the role of expertise in the building preservation. In the case of wooden towns, experts’ early recognition was a crucial precondition for the preservation of the heritage, which enabled novel generations to form a living relationship with it. Seen through the experts’ writings, the heritagisation process of the wooden towns also reflect the expanding scope of the built heritage discipline. Based on our findings, the canonisation model is applicable not only to the individual oevres, as Bonta addresses, but also to broader built environments and, more conceptually, to heritage categories.
International Journal of Building Pathology and Adaptation, 2020
Purpose - Ageing populations induce needs to adapt existing housing. With ageing, the number of f... more Purpose - Ageing populations induce needs to adapt existing housing. With ageing, the number of frail old people, who require assistance in daily life, is also increased. Converting existing housing into assisted living enables them to remain in their community while receiving necessary support and care. The purpose is to investigate whether postwar mass housing is spatially appropriate for adaptation into group homes for older people.
Design/methodology/approach - The research material is attained from Finland. Spatial requirements for group homes are drawn from 130 units built or renovated during 2000-2015. Spatial characteristics of mass housing are mapped from 105 apartment buildings built in the 1970s. The latter are matched with the former by comparing the connectivity of layouts, sizes of units and the numbers and sizes of individual spaces.
Findings - Group homes typically utilize a linear layout, which can easily be created in apartment buildings. Individual spaces of a group home fit apartment buildings effortlessly. Whole group home units mostly prove to be spatially feasible but result in looser dimensioning than is typical in existing units. The mass housing stock can be considered a spatial reserve for adaptation into group homes.
Originality/value - This is the first study to employ a large-scale, multi-case spatial mapping approach to analyse the adaptability properties of mass housing into assisted living. The findings pertain primarily to the Finnish context, but a methodology is presented which can be applied to other countries and also to other spatial functions.
Journal of Cultural Heritage Management and Sustainable Development, 2019
Purpose
The purpose of this paper is to discuss the relation between building conservation and c... more Purpose
The purpose of this paper is to discuss the relation between building conservation and circular economy (CE), which are often erroneously seen as inherently contradictory to one another.
Design/methodology/approach
The work draws from a comparative approach. The paper reviews a body of literature on architectural conservation and CE to establish an understanding on the state-of-the-art for both disciplines separately. Then, the relation between thereof is developed through a theoretical discourse.
Findings
Both architectural conservation and CE aim at safeguarding value, although they define “value” differently. Fabric-focused conservation and CE favor minimal intervention to material, albeit they arrive at this conclusion from different bases. Consequently, both approaches struggle with the low cost of virgin resource extraction and waste production and the high cost of human labor in contemporary Western societies. CE could be harnessed for building conservation by adopting its vocabulary and methodology, such as lifecycle assessment and material flow analysis. Transitioning toward CE can help increase the preservation of built heritage while redefining what is meant by “heritage” and “waste.”
Originality/value
Prior to this paper, there have been no articles addressing the relationship of the concepts explicitly and to this extent. The paper provides a theoretical basis for further discourse and outlines some implications of CE for the construction and built heritage disciplines.
Art historian Juan Pablo Bonta has presented a nine-step model for analysing how the interpretati... more Art historian Juan Pablo Bonta has presented a nine-step model for analysing how the interpretation of architectural oeuvres becomes canonised. We suggest that in terms of the built heritage, canonisation and heritagisation are essentially the same process, so Bonta’s model can be used for analysing heritagisation processes. This article testifies to this assumption by examining how the interpretation of historic Nordic wooden towns became stabilised in Finland. The concept was introduced in the 1960s to describe the Nordic urban heritage that was threatened by massive town development projects. The identification of the heritage category enabled the preservation of some remaining wooden districts. Examining this process allows us to discuss the role of expertise in the building preservation. In the case of wooden towns, experts’ early recognition was a crucial precondition for the preservation of the heritage, which enabled novel generations to form a living relationship with it. Seen through the experts’ writings, the heritagisation process of the wooden towns also reflect the expanding scope of the built heritage discipline. Based on our findings, the canonisation model is applicable not only to the individual oevres, as Bonta addresses, but also to broader built environments and, more conceptually, to heritage categories.
In Western Europe, many large housing estates have experienced spirals of intertwined physical an... more In Western Europe, many large housing estates have experienced spirals of intertwined physical and social decline. Such estates have wound up at the bottom of the housing hierarchy, which is manifested as high turnovers and vacancies. This qualitative multi-case study contributes to the research on the sustainable management of declining neighbourhoods’ housing stocks. The study learns from four individual cases in which vacancies were tackled with an extreme architectural transformation. In the investigated cases, large-panel buildings were partially deconstructed and renovated, and the reclaimed concrete panels were reused for new construction nearby. The approach integrates demolition, renovation and new construction − the three characteristic building stock management strategies in disadvantaged neighbourhoods. The cases are located in Sweden (Gothenburg, 1984), the Netherlands (Middelburg, 1986), Germany (Berlin, 2004) and Finland (Raahe, 2010). Deconstruction was the landlords’ way to manage their assets in the face of vacancies and social problems in relatively young, unamortized buildings. The projects proved technically feasible, yet they have been criticised for their economic and social implications. Nonetheless, the approach seems to have contributed to extending the life cycles of the buildings in question, and it has the potential to improve the quality of life in large housing estates.
In the fields of archaeology, art history and history, spolia have traditionally been studied as ... more In the fields of archaeology, art history and history, spolia have traditionally been studied as phenomena of the past. Today, the reuse of salvaged construction components and materials is primarily justified by its economic and ecological benefits, while its architectural and experiential qualities are much less discussed, if at all. Therefore, this article has two focuses, one more conceptual, and the other, more practical. Firstly, the article suggests extending the concept of spolia to contemporary architecture and discusses the usefulness of the concept in evaluating experiential values in contemporary constructions that make use of reclaimed parts. Secondly, it evaluates the potential of spoliation as a modern design tool in search of a more complex and historicity-based architectural expression. This potential is examined by defining the requirements for the extended concept and through analyzing examples of contemporary design. Although the main focus of this article is on contemporary architecture based on old building components, the topic also has obvious implications for heritage management.
This report discusses all the relevant EU, national and local level regulations that must be cons... more This report discusses all the relevant EU, national and local level regulations that must be considered when deconstructing or reusing concrete elements in the ReCreate project countries (Finland, Sweden, the Netherlands, and Germany). The results presented in the document are mostly based on desk studies which are, in some sections, complemented with interviews of authorities. The interviews were used particularly in sections that discuss norms whose practical implications contain ambiguities. However, although the interviews clarify some matters, the aim of the report is not per se to draw definitive conclusions on all the issues discussed in the document. This will be done in a future report (ReCreate deliverable D8.3.) that will complement theoretical or analytical perspectives of this document with the empirical insights and experiences from the pilots. The document is divided into two main chapters, which will discuss the most relevant norms on (1) deconstruction of precast concrete elements, and (2) the reuse of such elements. The chapter on deconstruction explores regulations which govern deconstruction permits, waste management, local environmental protection, and occupational safety. The chapter on reuse discusses the requirements set by regulation on technical matters, designer qualifications, product approval, and building permits. In addition, the chapter investigates what impact sustainability policies have on reuse of building components. All the norms are discussed in the document from the viewpoint of reusing precast concrete elements or, more generally, building components. This way, the goal is to keep observations of the document as practically relevant as possible. The document ends with a discussion chapter drawing conclusions on the state of re-use norms in different countries. Furthermore, the conclusions examine such crosscutting topics or groups of issues among the countries which hinder the development of reuse in ReCreate countries. The chapter suggests that the following topics should receive attention from developers who aim to overcome the legislative barriers: (1) Interpretation and practical implications of waste legislations, (2) a clarification of technical requirements for reused building components, (3) the product approval of reused components, and (4) concretization of sustainability policies. These issues will be at the hearth of the future ReCreate report (D8.3) as well.
A process for ensuring the properties of deconstructed precast concrete elements is essential for... more A process for ensuring the properties of deconstructed precast concrete elements is essential for safe reuse. The properties are important for structural designers when designing a new building with reused elements and evaluating their structural capacity and service-life. The ReCreate project researches the process of reusing precast concrete elements through four real-life deconstruction and reuse pilots in Europe. The aim is to study different aspects of the whole process, including quality assurance. To reuse precast concrete elements safely, it is essential to ensure their material properties. Especially when reusing load-bearing structures, certain properties, such as compressive strength, reinforcement details and cover depth of reinforcement, are required for evaluating structural capacity. However, the requirements for testing depend on the requirements of the new application, as the durability requirements may be different in different applications. This document describes the tests done in each of ReCreate’s four real-life pilots in the different countries (Finland, Sweden, the Netherlands, and Germany).
A quality management procedure for ensuring the safe reusability of deconstructed precast concret... more A quality management procedure for ensuring the safe reusability of deconstructed precast concrete elements is essential for more widespread and mainstreamed reuse. The quality of reclaimed elements should be maintained throughout the process, and any reductions thereof that may have occurred must be reliably identified. The ReCreate project researches reusing precast concrete elements, not originally designed for disassembly, through real-life deconstruction and reuse pilots in four European countries. The project covers all essential aspects of the whole reuse process, including quality management. For reuse to be safe and to have potential for business profitability, the quality and value of precast concrete elements must be consciously managed throughout different process phases. Reusability in high-value applications can be ensured with the help of a systematic quality management procedure, which has dedicated stages for the different phases of the overall reuse process. The quality of the elements can be inadvertently reduced in each stage, and thus the possible reducing factors need to be considered individually. This document presents the initial outline for the quality management procedure under development in the project. The key process stages are: • Pre-deconstruction audit, where the main actions are finding out the type and number of elements, assessing their reuse potential, and gathering information for the next stages. • Structural investigation, where the main actions are ensuring material properties of elements primarily with non-destructive (ND) or semi-destructive (SD) methods, determining the condition of the elements, and finding out the existence of possible hazardous substances. • Deconstruction design and execution, where the determination of safe deconstruction and lifting methods is the main action, together with transportation and storage of deconstructed elements. • Full-scale testing is carried out if the structural capacity of reclaimed elements cannot be uncovered through other means or if there is doubt about safety factors. Also newly developed retrofit connections need testing if original connections cannot be reused. • Redesign and reassembly, where the main actions are designing the reclaimed elements according to Eurocodes and standards in force. Also, the refurbishment of the reclaimed elements must be designed. • Product approval and authorisation is the final stage, where documents from the previous stages, together with technical drawings and calculations, will be presented to authorities to obtain official permits for reuse. Visual investigation and thorough documentation are an essential part of each stage. Information must be carried through from stage to stage. The current report presents the key process stages, along with a discussion on factors that may reduce the quality of salvaged elements and which must thus be addressed. By the end of the project, this outline will be developed into a best practice proposal, which will be published as a separate deliverable.
The BIM-aided pre-deconstruction audit process is mainly a process of collecting and digitalizing... more The BIM-aided pre-deconstruction audit process is mainly a process of collecting and digitalizing data of precast concrete elements in a donor building, from which they will be deconstructed. The digital information is stored in a database that architects and structural designers can use when designing a new building with reused precast concrete elements. The ReCreate project tests the process of harvesting and reuse of precast concrete elements in four real-life projects in Europe. The goal is to gather knowledge in a wide range of topics directly connected to the reuse of precast concrete elements in structures of new buildings. By reusing these elements, they get a second life and the environmental impact of construction a new building is significantly reduced. The insights gained in the pilot projects contribute to a kind of ‘roadmap’ for collection information on donor buildings and their precast concrete elements in what we call a ‘pre-deconstruction audit’ (as opposed to the more familiar ‘pre-demolition audit’). The audit process contains all the steps necessary to start an efficient and (structurally) safe deconstruction process of a donor building. The audit process starts by collecting data from various archives and the internet, such as Google Maps and Street View. The data is entered into a visual database, a 3D BIM model. This 3D BIM model offers great advantages in managing and validating the collected data. To validate the data, determine its reliability and complete missing data, a visual inspection is performed. Additional testing supports the data and the reliability of the data. The information obtained is incorporated into the 3D BIM model in order to create a final, complete and reliable 3D BIM database containing all the necessary information of the precast concrete elements. The roadmap for collecting the data, creating a 3D BIM model (database), verifying and managing the data of the donor building and precast elements is laid down in this document as a recommendation.
The ReCreate project researches deconstruction and reuse of precast concrete elements, not origin... more The ReCreate project researches deconstruction and reuse of precast concrete elements, not originally designed for disassembly. ReCreate’s real-life pilots are a significant tool for achieving this goal. This report describes and illustrates ReCreate’s deconstruction pilots. Six real-life deconstructions of precast concrete buildings – one in Finland, two in Sweden, one in the Netherlands, and two in Germany – are used in the ReCreate project to generate theoretical and practical knowledge about a wide range of topics directly related to the process of salvaging and reusing precast concrete elements. While the learnings regarding the planning and implementation of deconstruction are described in a centralised manner in another report (Vullings et al. 2024), the current report documents the donor buildings of the secondary elements as well as their practical deconstruction processes through textual descriptions and generous photographic illustrations and drawings. The donor buildings were blocks of flats (three buildings), public and private office buildings (two buildings) and industrial/warehouse buildings (one building). They had been deemed obsolete and were therefore slated for demolition. When engaged in ReCreate, they instead became vessels of knowledge generation for reuse-minded deconstruction. The various elements reclaimed from the donor buildings, such as sandwich panels, massive concrete slabs, massive interior wall elements, hollow core slabs, beams, and columns, will be reused in future in ReCreate’s reuse pilots. In addition to ReCreate’s six donor buildings, insights from following and observing two additional deconstructions, external to ReCreate, are also reported on herein.
The ReCreate project researches deconstruction and reuse of precast concrete elements, not origin... more The ReCreate project researches deconstruction and reuse of precast concrete elements, not originally designed for disassembly. Real-life deconstructions of precast concrete buildings in four countries (Finland, Sweden, the Netherlands and Germany), performed by ReCreate’s industrial partners as well as collaborators to harvest elements for reuse, were a key tool to gain experience and insights into deconstruction techniques and processes. The current report delivers an overview of what deconstruction entails. It gives best practice guidelines on the planning and implementation of deconstruction, as well as recommendations for improving the process. While ReCreate’s country-specific deconstruction pilots themselves are described in a dedicated report (Vullings et al. 2024), they are also briefly summarised in the beginning of this report. The focus of the current report is, nevertheless, on turning the learnings from deconstruction pilots into generalisable guidelines that can be capitalised beyond the ReCreate project and the parties involved. Deconstruction entails four main phases: pre-planning, structural deconstruction planning, deconstruction work planning, and finally, implementing the deconstruction. This report instructs on the different types of plans involved in each stage as well as their authors and contents. Pre-planning involves pre-deconstruction auditing, i.e. inventorying reusable elements and gathering relevant information into an ‘inventory’ Building Information Model (BIM). The pre-deconstruction audit has been covered by another ReCreate deliverable (Vullings et al. 2022), which was delivered before ReCreate’s deconstruction pilots were fully complete. Therefore, the current deliverable briefly recaps the essentials of a BIM-based pre-deconstruction audit, and supplements and consolidates the findings of the previous report. Authored by a qualified structural engineer, a structural deconstruction plan sets the foundations for a safe and efficient deconstruction process. it defines the deconstruction sequence based on structural stability; determines the need for temporary support and bracing measures; establishes cutting spots for connectors; gives a labelling scheme for logistics; instructs on correct lifting and transport of elements as well as how to monitor the quality of elements on-site; and can help to define requirements for stripping. A deconstruction work plan, devised by experts of the deconstruction company, translates the structural deconstruction plan into work processes: both the overall deconstruction process as well as element type specific processes. It covers aspects like workforce, equipment, work safety, site planning and scheduling. Finally, learnings acquired by implementing ReCreate’s deconstruction pilots are elaborated on. Findings are reported on deconstructing different types of elements; avoidable mistakes that were made which may influence the reusability (or at least the effort and cost of reuse) of the salvaged elements; the types of damage that is not easily preventable but an inherent part of deconstruction; and the influence of weather conditions on the deconstruction work. Additionally, special types of deconstruction projects are briefly discussed, such as partial deconstruction in the context of building remodelling, as well as combining deconstruction with conventional demolition. While smaller, sub-process specific insights are scattered through the report, the main learnings of the key topics are distilled into checklists, given at the end of this report. The experience of the ReCreate deconstruction pilots shows that prerequisites for more widespread deconstruction already exist in that appropriately skilled workforce and suitable tools and equipment are widely available. The main technical and processual challenge in deconstruction is reconfiguring the existing know-how into safe and efficient deconstruction processes. This development can be further supported by small adjustments to existing tools that can help make the equipment even better suitable for deconstruction purposes. Nevertheless, it should be noted that a full evaluation of the success of ReCreate’s deconstruction pilots can only be made once the salvaged elements have been reused in new buildings.
The depletion of non-renewable natural resources and generation of waste is one of the key issues... more The depletion of non-renewable natural resources and generation of waste is one of the key issues to be addressed to achieve sustainable goals of the modern society. A great amount of natural resources consumption and a significant part of waste production is contributed to the building industry and infrastructure, in particular construction, maintenance and demolition. Moreover, production of building materials (even those with a high recycled content) consumes a lot of energy and produces harmful emissions. Therefore the efficient use of resources implies that the durable building materials and elements produced from such materials should be used as long as possible regardless of the limitation of the building service life. The most challenging building parts are the load-bearing structures because they need to satisfy high quality and strength, structural safety, stability and integrity requirements.
Tampere University of Technology. Publication 1414.
Building stocks will play growing roles in the extraction of secondary construction materials in ... more Building stocks will play growing roles in the extraction of secondary construction materials in future. Moreover, as there is a need to decouple buildings’ service provision from their material consumption, building stocks should, in fact, be considered not only as deposits of raw materials but also as reserves of space. Despite of their significance, these stocks tend neither to be well known nor systematically analysed. The end-of-life phase of buildings is especially poorly covered in research, although the aspects of buildings’ mortality and survival are fundamentally intertwined. The omission is highly problematic, because it precludes understanding the fundamental dynamics of the stock.
The current study is situated in Finland, where the basic composition of the stock is relatively well established in the Building and Dwelling Register, contrary to many other countries. Taking advantage of statistical description, this dissertation explores the geography and characteristics of obsolete parts of the Finnish building stock, that is, demolished and problematically vacant buildings. The dynamics, or the relations, within the stock are also considered on a very basic level, with the help of a simple correlation analysis. In order to exemplify refining the results of this kind of top-down research, the study then switches to a bottom-up approach and zooms into the more specific composition of a selected age-use cohort, the 1960–80s blocks of flats. The types and dimensions of the cohort’s components, or concrete panels, are inventoried, and the results are compared to the current requirements for dimensioning living spaces. Furthermore, the spatial configurations of flats, the service provided by these physical structures, are also investigated using graph theory informed typological methodology. The findings consist of a typology of flats characteristic to the cohort. Lastly, the extents of the reserves in the entire stock of demolished buildings, the stock of problematically vacant residential buildings and the exemplary cohort (its existing, vacant and demolished parts) are quantified and proportioned to each other and new construction, inter alia.
By highlighting the magnitudes of secondary deposits of materials, components and spaces, this dissertation suggests that public policy should start paying more attention to the building stock and the potentials embedded within it. Even though an unambiguous relation between vacancy and demolition was not identified, the key finding from the resource perspective is that significant amounts of obsolete buildings are geographically concentrated on cities. In order to practice sustainable policies on the building stock, planners and decision-makers should be better aware of these reserves and acknowledge their adaptation and modification capacities.
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Papers by Satu Huuhka
Policy relevance
This paper reinforces the notion from previous research that developing the existing building stock holds major emission-savings potential, even more so than replacement with energy-efficient new build. It highlights the potential contribution of existing building stocks in low-emission city development, even in growing city contexts. The case study results challenge the common belief in urban planning that if replacement involves densification, it must be a more low-emission alternative than retention, and conversely, if retention leads to greenfield construction, it must be higher in emissions than replacement. Low-emission urban planning should base its conclusions on urban LCA. This paper introduces an infrastructure-extended CRF that accounts for building retention and replacement scenarios, ensuring methodological robustness. The approach is essential for policymakers to base their decisions on evidence and prioritise low-emission development alternatives. Which policymakers hold power over such decisions and which instruments are suitable to pursue these goals depend on the context.
The results show that growth in population and labour force led to a substantial increase in both cities’ building stocks. While Vantaa’s more rural character allowed a higher amount of sprawl by loose-built housing typologies, geographical restrictions and the already dense building stock in Tampere often led to more compact housing and an overall higher amount of demolition in relation to construction. The development of both non-residential building stocks shows a clear tendency towards typologies that support respective economic operations. Alas, material intensity coefficients, which would enable quantifying the material and CO2 impacts of these developments, do not yet exist for Finnish building typologies. Nevertheless, this study’s findings provide a preliminary understanding of how different mechanisms of urban development, such as construction and demolition, shape environmental strains and support the development of pinpoint circular strategies.
Policy relevance
As the global CO2 budget is running out, the need to combat the escalation of the climate emergency is imminent. Decades-long payback times for embodied CO2 investments in new replacement buildings, as in the paper’s case studies, are not helpful in this effort. The introduced framework helps to uncover the climate change mitigation potential in building preservation, which is presently poorly understood and considered in policymaking. The new framework provides a useful decision support tool and evidence for both policymakers and planners. Current policy initiatives in Europe focus on CO2 regulation for new build and renovation. However, replacement situations are not yet regulated. In contexts where renovation clearly proves to be more climate friendly (as validated by this method), policymakers should recognise the greenhouse gas-mitigation potential in building retention and create policies to encourage renovation over new build.
Practice relevance
In the adaptability discourse, residents’ opinions have been heard to a very limited degree. More typically, adaptability researchers or architects make the case for adaptability on the residents’ behalf. According to recent research, some architects assume developers are disinterested in building more adaptable flats partly because no real market demand by inhabitants is believed to exist. The findings of the current study demonstrate that residents need to be properly informed about the benefits of adaptability by the housing provider. Virtual reality can be a useful tool for demonstrating adaptability characteristics. When sufficiently informed, the participants of the current study considered adaptability as functionally beneficial for the family and a desirable feature that would increase their willingness to buy and pay a premium. To demonstrate a potential market or its absence in a given context, residents’ views should be sought more widely and more often.
Design/methodology/approach - The research material is attained from Finland. Spatial requirements for group homes are drawn from 130 units built or renovated during 2000-2015. Spatial characteristics of mass housing are mapped from 105 apartment buildings built in the 1970s. The latter are matched with the former by comparing the connectivity of layouts, sizes of units and the numbers and sizes of individual spaces.
Findings - Group homes typically utilize a linear layout, which can easily be created in apartment buildings. Individual spaces of a group home fit apartment buildings effortlessly. Whole group home units mostly prove to be spatially feasible but result in looser dimensioning than is typical in existing units. The mass housing stock can be considered a spatial reserve for adaptation into group homes.
Originality/value - This is the first study to employ a large-scale, multi-case spatial mapping approach to analyse the adaptability properties of mass housing into assisted living. The findings pertain primarily to the Finnish context, but a methodology is presented which can be applied to other countries and also to other spatial functions.
The purpose of this paper is to discuss the relation between building conservation and circular economy (CE), which are often erroneously seen as inherently contradictory to one another.
Design/methodology/approach
The work draws from a comparative approach. The paper reviews a body of literature on architectural conservation and CE to establish an understanding on the state-of-the-art for both disciplines separately. Then, the relation between thereof is developed through a theoretical discourse.
Findings
Both architectural conservation and CE aim at safeguarding value, although they define “value” differently. Fabric-focused conservation and CE favor minimal intervention to material, albeit they arrive at this conclusion from different bases. Consequently, both approaches struggle with the low cost of virgin resource extraction and waste production and the high cost of human labor in contemporary Western societies. CE could be harnessed for building conservation by adopting its vocabulary and methodology, such as lifecycle assessment and material flow analysis. Transitioning toward CE can help increase the preservation of built heritage while redefining what is meant by “heritage” and “waste.”
Originality/value
Prior to this paper, there have been no articles addressing the relationship of the concepts explicitly and to this extent. The paper provides a theoretical basis for further discourse and outlines some implications of CE for the construction and built heritage disciplines.
Policy relevance
This paper reinforces the notion from previous research that developing the existing building stock holds major emission-savings potential, even more so than replacement with energy-efficient new build. It highlights the potential contribution of existing building stocks in low-emission city development, even in growing city contexts. The case study results challenge the common belief in urban planning that if replacement involves densification, it must be a more low-emission alternative than retention, and conversely, if retention leads to greenfield construction, it must be higher in emissions than replacement. Low-emission urban planning should base its conclusions on urban LCA. This paper introduces an infrastructure-extended CRF that accounts for building retention and replacement scenarios, ensuring methodological robustness. The approach is essential for policymakers to base their decisions on evidence and prioritise low-emission development alternatives. Which policymakers hold power over such decisions and which instruments are suitable to pursue these goals depend on the context.
The results show that growth in population and labour force led to a substantial increase in both cities’ building stocks. While Vantaa’s more rural character allowed a higher amount of sprawl by loose-built housing typologies, geographical restrictions and the already dense building stock in Tampere often led to more compact housing and an overall higher amount of demolition in relation to construction. The development of both non-residential building stocks shows a clear tendency towards typologies that support respective economic operations. Alas, material intensity coefficients, which would enable quantifying the material and CO2 impacts of these developments, do not yet exist for Finnish building typologies. Nevertheless, this study’s findings provide a preliminary understanding of how different mechanisms of urban development, such as construction and demolition, shape environmental strains and support the development of pinpoint circular strategies.
Policy relevance
As the global CO2 budget is running out, the need to combat the escalation of the climate emergency is imminent. Decades-long payback times for embodied CO2 investments in new replacement buildings, as in the paper’s case studies, are not helpful in this effort. The introduced framework helps to uncover the climate change mitigation potential in building preservation, which is presently poorly understood and considered in policymaking. The new framework provides a useful decision support tool and evidence for both policymakers and planners. Current policy initiatives in Europe focus on CO2 regulation for new build and renovation. However, replacement situations are not yet regulated. In contexts where renovation clearly proves to be more climate friendly (as validated by this method), policymakers should recognise the greenhouse gas-mitigation potential in building retention and create policies to encourage renovation over new build.
Practice relevance
In the adaptability discourse, residents’ opinions have been heard to a very limited degree. More typically, adaptability researchers or architects make the case for adaptability on the residents’ behalf. According to recent research, some architects assume developers are disinterested in building more adaptable flats partly because no real market demand by inhabitants is believed to exist. The findings of the current study demonstrate that residents need to be properly informed about the benefits of adaptability by the housing provider. Virtual reality can be a useful tool for demonstrating adaptability characteristics. When sufficiently informed, the participants of the current study considered adaptability as functionally beneficial for the family and a desirable feature that would increase their willingness to buy and pay a premium. To demonstrate a potential market or its absence in a given context, residents’ views should be sought more widely and more often.
Design/methodology/approach - The research material is attained from Finland. Spatial requirements for group homes are drawn from 130 units built or renovated during 2000-2015. Spatial characteristics of mass housing are mapped from 105 apartment buildings built in the 1970s. The latter are matched with the former by comparing the connectivity of layouts, sizes of units and the numbers and sizes of individual spaces.
Findings - Group homes typically utilize a linear layout, which can easily be created in apartment buildings. Individual spaces of a group home fit apartment buildings effortlessly. Whole group home units mostly prove to be spatially feasible but result in looser dimensioning than is typical in existing units. The mass housing stock can be considered a spatial reserve for adaptation into group homes.
Originality/value - This is the first study to employ a large-scale, multi-case spatial mapping approach to analyse the adaptability properties of mass housing into assisted living. The findings pertain primarily to the Finnish context, but a methodology is presented which can be applied to other countries and also to other spatial functions.
The purpose of this paper is to discuss the relation between building conservation and circular economy (CE), which are often erroneously seen as inherently contradictory to one another.
Design/methodology/approach
The work draws from a comparative approach. The paper reviews a body of literature on architectural conservation and CE to establish an understanding on the state-of-the-art for both disciplines separately. Then, the relation between thereof is developed through a theoretical discourse.
Findings
Both architectural conservation and CE aim at safeguarding value, although they define “value” differently. Fabric-focused conservation and CE favor minimal intervention to material, albeit they arrive at this conclusion from different bases. Consequently, both approaches struggle with the low cost of virgin resource extraction and waste production and the high cost of human labor in contemporary Western societies. CE could be harnessed for building conservation by adopting its vocabulary and methodology, such as lifecycle assessment and material flow analysis. Transitioning toward CE can help increase the preservation of built heritage while redefining what is meant by “heritage” and “waste.”
Originality/value
Prior to this paper, there have been no articles addressing the relationship of the concepts explicitly and to this extent. The paper provides a theoretical basis for further discourse and outlines some implications of CE for the construction and built heritage disciplines.
The current study is situated in Finland, where the basic composition of the stock is relatively well established in the Building and Dwelling Register, contrary to many other countries. Taking advantage of statistical description, this dissertation explores the geography and characteristics of obsolete parts of the Finnish building stock, that is, demolished and problematically vacant buildings. The dynamics, or the relations, within the stock are also considered on a very basic level, with the help of a simple correlation analysis. In order to exemplify refining the results of this kind of top-down research, the study then switches to a bottom-up approach and zooms into the more specific composition of a selected age-use cohort, the 1960–80s blocks of flats. The types and dimensions of the cohort’s components, or concrete panels, are inventoried, and the results are compared to the current requirements for dimensioning living spaces. Furthermore, the spatial configurations of flats, the service provided by these physical structures, are also investigated using graph theory informed typological methodology. The findings consist of a typology of flats characteristic to the cohort. Lastly, the extents of the reserves in the entire stock of demolished buildings, the stock of problematically vacant residential buildings and the exemplary cohort (its existing, vacant and demolished parts) are quantified and proportioned to each other and new construction, inter alia.
By highlighting the magnitudes of secondary deposits of materials, components and spaces, this dissertation suggests that public policy should start paying more attention to the building stock and the potentials embedded within it. Even though an unambiguous relation between vacancy and demolition was not identified, the key finding from the resource perspective is that significant amounts of obsolete buildings are geographically concentrated on cities. In order to practice sustainable policies on the building stock, planners and decision-makers should be better aware of these reserves and acknowledge their adaptation and modification capacities.