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Replacement or reuse? The choice between demolition and life cycle extension from a sustainable viewpoint
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What is better: renovation or new construction? Following the plenary debate on the ENHR 2007 conference in Rotterdam we continued our search for the answer to this question. The choice between reuse and replacement of existing buildings is a vital but very difficult one, involving a wide range of aspects and affecting contradictory and often conflicting interests. In the past, building quality and public health played a decisive role in improvement of the housing stock, mainly by slum clearance. More recently functional and economic considerations tend to dominate. Though environmental aspects like energy consumption and building waste are of growing importance, sustainability does not seem to be a major aspect in decision making about demolition or life cycle extension up till now. In the past years we studied the decision making about demolition in the Netherlands. Based on the available literature and statistical data we analysed the actual practice in the Netherlands to identify the ‘demolishers’ and their motives. In addition to this research we made an inventory of the literature about the environmental impact of reuse and replacement. Our paper gives a concise overview of the results. Overlooking the results so far we conclude that life cycle extension by renovation and reuse of existing stock is generally more sustainable. However replacement seems to increase in the Netherlands. Therefore we discuss ways to stimulate ‘demolishers’ to give more weight to sustainability and pay more attention to reuse.
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... The objective of a transformation process is instead a comprehensive and ideally endless extension of the life span of a building, throughout modifications of its physical, functional, architectural and ecological characteristics (van der Flier & Thomsen, 2006;Thomsen & van der Flier, 2008;Thomsen, 2011). Life-cycle extension is often more sustainable than replacement (de Jonge, 2005;Gruis at al., 2006), which must be considered as the last resort, and it is also coherent with the conception of the building as a set of different layers (Brand, 1995;Leupen, 2006), each one with a different useful life. ...
... From the environmental point of view, transformation processes are more efficient than replacements because they exploit all the pre-existing materials, requiring four to eight times less resources (Itard & Klunder, 2007;Thomsen & van der Flier, 2008) while demolitions are the biggest source of landfill by volume, with around 30% of the total (Power, 2008). ...
... From a financial point of view, demolition and new construction is only worth and it is the last resort if the house is in such bad state that extensive, cost-intensive measures are needed, not justifying the investment (Thomsen & van der Flier, 2008). ...
This doctoral thesis presents technical strategies for the rational maintenance of the building heritage directed
at the integrated retrofit of social housing stocks.
The study comprised the analysis of recovered residential buildings in order to develop new sceneries to adopt
in critical situations, leading to the definition of a new experimental practice called “adaptive exoskeleton”.
This strategy involves the wrapping of the entire original building with a three-dimensional structural envelope,
the exoskeleton, using a construction process able to limit interferences on the use of the building and on the
life of its inhabitants. The exoskeleton is an independent frame, carefully designed at the joint-scale to achieve
awareness of the constructive sequence and of the optimization of the resources. Dry construction technologies resulted to be the most effective, because based on the principles of lightness and reversibility, and because they allow to realize a structural grid able to satisfy different standards in relation to the changing user conditions.
The strategy of the adaptive exoskeleton, which exploits optimized and industrialized components, appears
convenient in relation to large-scale interventions on the built heritage and, at the same time, it is
architectonically versatile, with many possible options adaptable to different cultural contexts. The structural frame can be adjusted to different dimensions, extensions, typologies and technologies, maintaining the same basic characteristics. Passive dissipative devices realized with shape memory alloys, strategically located as connectors with the existing building, are used in order to reduce the lateral displacements during earthquakes. A key idea is the separation between the long lasting elements of the construction, such as the structural systems, and the parts that can be updated progressively in relation to the requirements of the user or to the technological innovations. This principle is convenient in large-scale campaigns, where it is necessary to create a solid base structure without renouncing to the individualization and the variety of the demand, which stimulates the introduction of architectural components with a shorter use-life.
The structural characteristics of this construction and its ability to dissipate the seismic input, were analysed
during a research period of twelve months undertaken at the Eindhoven University of Technology (Netherlands) at the unit of Innovative Structural Design of the Built environment department. The verification phase considered two building typologies, due to their high diffusion in Europe: the use of the finite element software SAP2000 required the application of a “frame model” for masonry buildings and of a “strut model” for the concrete frame with masonry infill.
The seismic behaviour of the buildings was analysed before any intervention and after the introduction of the
adaptive exoskeleton implemented with shape memory alloys-based devices. The experimental phase was also undertaken with reference to San Bartolomeo estate in Brescia, Italy.
Summarizing, the research underlined the convenience of applying retrofit processes in opposition with
demolitions and reconstructions, above all in terms of social and environmental costs. The adaptive exoskeleton, in particular, provides an integrated and synergic solution because while improving the seismic behaviour of the structure, offers additional space for services and functions, increasing the economic value of the building and improving its energy performances and its architectural characteristics.
... In addition, the energy performance of a renovated building could be equal to that of a new building. Thus, the argument that the lifespan expectation and market position of a renovated building can be insufficient to justify the investment is not convincing (Thomsen & van der Flier, 2008). ...
The challenges to which contemporary building design needs to respond grow steadily. They originate from the influence of changing environmental conditions on buildings, as well as from the need to reduce the impact of buildings on the environment. The increasing complexity requires the continual revision of design principles and their harmonisation with current scientific findings, technological development, and environmental, social, and economic factors. It is precisely these issues that form the backbone of the thematic book, Sustainable and Resilient Building Design: Approaches, Methods, and Tools. The purpose of this book is to present ongoing research from the universities involved in the project Creating the Network of Knowledge Labs for Sustainable and Resilient Environments (KLABS). The book starts with the exploration of the origin, development, and the state-of-the-art notions of environmental design and resource efficiency. Subsequently, climate change complexity and dynamics are studied, and the design strategy for climate-proof buildings is articulated. The investigation into the resilience of buildings is further deepened by examining a case study of fire protection. The book then investigates interrelations between sustainable and resilient building design, compares their key postulates and objectives, and searches for the possibilities of their integration into an outreaching approach. The fifth article in the book deals with potentials and constraints in relation to the assessment of the sustainability (and resilience) of buildings. It critically analyses different existing building certification models, their development paths, systems, and processes, and compares them with the general objectives of building ratings. The subsequent paper outlines the basis and the meaning of the risk and its management system, and provides an overview of different visual, auxiliary, and statistical risk assessment methods and tools. Following the studies of the meanings of sustainable and resilient buildings, the book focuses on the aspects of building components and materials. Here, the life cycle assessment (LCA) method for quantifying the environmental impact of building products is introduced and analysed in detail, followed by a comprehensive comparative overview of the LCA-based software and databases that enable both individual assessment and the comparison of different design alternatives. The impact of climate and pollution on the resilience of building materials is analysed using the examples of stone, wood, concrete, and ceramic materials. Accordingly, the contribution of traditional and alternative building materials to the reduction of negative environmental impact is discussed and depicted through different examples. The book subsequently addresses existing building stock, in which environmental, social, and economic benefits of building refurbishment are outlined by different case studies. Further on, a method for the upgrade of existing buildings, described as ‘integrated rehabilitation’, is deliberated and supported by best practice examples of exoskeleton architectural prosthesis. The final paper reflects on the principles of regenerative design, reveals the significance of biological entities, and recognises the need to assign to buildings and their elements a more advanced role towards natural systems in human environments.
... The end-of-life scenario of a building, when not abandoned, results in two major outcomes: demolition and new construction, or renovation. The selection of the most economically valuable, environmentally efficient, and socially beneficial solutions between new and renovated buildings is often a difficult process [6]. ...
The ageing of buildings is associated with their degradation. By the end of a building's operative life, two solutions are provided: demolition and new construction, or renovation. New construction can cause higher greenhouse gas equivalent emissions than renovations, related to higher demand for building materials, processes, and waste management. Conversely, building renovation requires greater effort in planning and implementation. Moreover, when improperly planned, renovation might ensure only limited improvements in building performance. This study presents three renovation systems based on hybrid timber technologies for three common case-study building types in the Republic of Korea: apartment, low-rise residential, and mixed-use (industrial–commercial). Following analysis of the current regulations for building component performance in Korea, three modular building envelope renovation systems have been developed: (i) cross-laminated timber, (ii) glue-laminated frame with integrated timber stud panels, and (iii) steel frame with integrated timber stud walls. The development of the three systems focuses on designing modular self-supporting components that allow both horizontal and vertical extension, and the structural support of occupied buildings. The hybrid timber-based construction provides a low-carbon alternative to demolition and new construction, helping to solve spatial constraints to renovation determined by the high urban density of Korean cities.
... In contrast, it has been discovered that the building envelope ages after 20 to 30 years already (Chandler 1992). However, studies have shown that the negative environmental impacts are lower if the life period of existing buildings is expanded (Thomsen and van der Flier 2008). Moreover, it is proven that renovation options lead to economic (Balaban and Puppim de Oliveira 2017) and socio-cultural (Broderick et al. 2017) benefits as well. ...
The 27th EG-ICE International Workshop 2020 brings together international experts working at the interface between advanced computing and modern engineering challenges. Many engineering tasks require open-world resolutions to support multi-actor collaboration, coping with approximate models, providing effective engineer-computer interaction, search in multi-dimensional solution spaces, accommodating uncertainty, including specialist domain knowledge, performing sensor-data interpretation and dealing with incomplete knowledge. While results from computer science provide much initial support for resolution, adaptation is unavoidable and most importantly, feedback from addressing engineering challenges drives fundamental computer-science research. Competence and knowledge transfer goes both ways.
... From an environmental perspective, the sustainability of urban redevelopment is linked to the possibility of upscaling existing buildings starting from the material and the energy they still contain [19][20][21]. The extraction of raw materials and the energy consumed in building production creates additional environmental pollution and climate-altering gases [22,23]. Demolition and reconstruction are less environmentally friendly: 20% of toxic waste comes from demolition, and most of the toxic materials are thrown into landfill without being properly recycled [24]. ...
Local administrators and private investors rely on various urban redevelopment strategies, the choice of which depends on the economic expectations of property owners and investors. Some of these options foresee replacing obsolete buildings with new constructions; others prefer the reuse of existing assets. This study examines the conditions that make these different strategies feasible, bringing to light the aspects that favor demolition and reconstruction processes over interventions based on the redevelopment of existing assets. The analysis focuses on the variables that determine the choice between these two options. The model that has been developed highlights, on one hand, the role of urban planning tools and urban densification and, on the other, the relationship between the land market and the value of existing assets. The model has been tested on five cities in northern Italy, which fall into three territorial categories—large metropolitan cities, medium-sized cities, and cities of limited rank—to test how different social and economic contexts affect the feasibility of the strategies we evaluated. The results of the study underscore the extent to which the demolition and reconstruction of existing assets is only viable in certain limited areas and under particular market and settlement conditions. While large metropolitan areas seem to have the option of radically replacing existing real estate assets, medium-sized cities and especially small cities are constrained in redeveloping existing urban assets and must forego demolition and reconstruction projects, which do not prove to be economically feasible.
... When it comes to environmental impact regarding waste and materials, retrofitting has been proved a suitable candidate compared to demolishing and reconstructing of existing buildings [20,21]. Since the existing stock of buildings is expected to be in use for next 50 In a simulation study, the building envelope in the presence of daylighting in offices was evaluated for the optimum window to wall ratio as well as the windows glazing methods. ...
Enormously increased energy consumption makes it inevitable to upgrade the energy efficiency of the existing stock of buildings which share a substantial part of the overall energy consumption worldwide. Being an effective tool for analyzing energy performance, Building Information Modelling (BIM), is used to enhance the energy performance of the buildings. This study, therefore, investigates the effectiveness of applying passive cooling techniques using BIM and focuses on developing recommendations on feasible and optimized retrofitting techniques for existing buildings. Moreover, it gives an economic comparison between initial investment and returns based on the quantitative results of energy retrofitting. Thermal simulation software Autodesk Ecotect has been used to simulate annual energy consumption of one case building. Different passive cooling techniques have been applied according to Building Energy Codes of Pakistan. The input parameters are, thus, type of insulating material, the thickness of insulating materials, single and double glazing of windows and window to wall ratio. Results indicate that the annual energy consumption of selected building can be reduced up to 35 % when building incorporates passive cooling techniques with a calculated payback period of 3 years and 2 months.
To redevelop the existing city without consuming additional land, there are many regeneration strategies. The choice between the various strategies depends essentially on the expectations of developers. This study considers two in particular: the demolition and reconstruction of obsolete buildings and the reuse of existing assets. The research examines the feasibility conditions of the two strategies, highlighting the aspects that favor demolition and reconstruction over reuse with a model that holds together spatial and economic variables. The model is tested in seven metropolitan cities. The results show that demolition and reconstruction is an option that can only be pursued under favorable settlement and market conditions, forcing smaller cities to focus on recovery strategies for existing assets.
Although the study of roofing systems (from coverings to structure of the roof) is of great significance to energy efficiency and sustainable development, design and construction of new roofs on top of existing roofs in buildings has not received sufficient attention. This study discusses re-roofing as one of the key options to reduce energy consumption and improve overall building performance. The more conventional choice and more frequently chosen option for building energy retrofit is vertical building envelope components, however, this paper presents the case study of a proposed retrofitting concept for the roof of an existing building. Using a simulation methodology, the research demonstrates how the proposed retrofitting concept improves the energy performance using electricity generated and external conduction gain as evaluation metrics. The proposed novel re-roofing concept consists of thermal insulation, waterproofing and electric energy generation properties. More specifically, the design concept includes a three-layer roofing system consisting of (from exterior toward interior): a PV panel, an EPDM membrane and an insulation layer. The main goal of this study is to develop a concept for an innovative re-roofing solution that demonstrates the feasibility of turning an old building into a watertight and energy producing system.
Upgrading the energy efficiency of existing buildings is a well-known issue around the globe. Given the very low renewal rate of the building stock, thermal retrofit of the existing buildings seems to be a good solution to improve the environmental performance of the building sector. Several studies have acknowledged the lack of knowledge, experience and best-practice examples as barriers in thermal retrofit of existing buildings. Therefore, this study has focused on developing recommendations on the most effective and feasible retrofitting techniques for existing buildings and performing financial analysis of initial investment vs. return based on the quantitative results of the energy modelling. Thermal comfort modelling software FirstRate5 has been used to simulate the annual heating and cooling energy consumption of nine benchmark buildings through a range of retrofitting techniques. Dwellings of varying construction materials including weatherboard, cavity brick and brick veneer have been simulated to improve accuracy. Examining seven different thermal retrofitting options in this study, it has become apparent that there is significant heating and cooling energy reduction, with pay-back period of less than three years, by implementing two options of the examined retrofitting cases to existing residential dwellings.
A credible model to account for the overall energy benefits with retention of historic buildings has been needed since preservation became national policy in 1966. The initial need to measure energy capital in buildings arose from the two energy crises in the 1970s, with a second need to address the sustainability goals of the 1990s/2000s. Both responses measure overall energy efficiency of historic buildings by attempting to account for the "energy capital." The Advisory Council on Historic Preservation introduced the first model in 1979, focused on measuring embodied energy and it has remained embedded in preservation vocabulary and is a reflexive argument utilized to advocate for the retention of historic structures over new construction. The second model, the life cycle assessment/avoided impacts is a response to the evolving metrics and currency of sustainability. The Preservation Green Lab further matured the capabilities of the life cycle assessment/avoided impacts model in 2012 with their innovative report, The Greenest Building: Quantifying the Environmental Value of Building Reuse. This thesis evaluates the future of the preservation field to communicate with a common currency regarding retention of historic structures.
General features of process evaluation
Six broad factors that might influence intervention outcomes
Activities related to refurbishment of the building stock as a percentage of all building work have been constantly growing in most central European countries over the last 20 years. The main argument in this paper is the need to improve knowledge about composition of the existing building stock, the dynamics of its transformation and to relate this to the different actors in property professions. A review is presented of traditional and new sectoral research approaches to partial or national building stocks to provide a context for assessing an integrated approach to the German building stock with methodological propositions for improving the synergy between different sectoral approaches. Detailed consideration is given to life cycle analysis, building product modelling, historical building research and new simulation techniques. Sustainability indicators and the integration of building stock, infrastructure and land use are discussed.
When undertaking urban renewal projects, decisions must be made between housing maintenance with some minor interventions, and total housing redevelopment entailing the demolition of the existing stock and replacement with new houses. Simple renovations are only possible if the quality of the existing dwelling is sufficient to fulfil current needs. In most urban renewal districts in the Netherlands the existing stock does not meet these current needs. That is why large-scale demolition and the construction of new dwellings are undertaken. However, renovation-based strategies could offer more sustainable alternatives. A comparison of the environmental impacts is made between the renewal options of maintenance, consolidation, transformation, and redevelopment for two typical cases of Dutch urban renewal. The environmental effects are calculated using the Life Cycle Assessment method. Results are presented according to the following environmental effects: the quantities of material, the energy and water used, waste, and environmental impacts. The use of environmental impacts gives a more complete picture than the use of quantities. The transformation of the existing housing stock is found to be a much more environmentally efficient way to achieve the same result than are demolition and rebuilding. The embodied and operational energy use is also compared. Due to the relatively short lifetime of post-war dwellings, the embodied energy can amount to 30% of the total energy use. This means that it is worth using construction methods that reduce embodied energy and designing new buildings so that they are flexible.
According to EC forecasts, if energy efficiency could be increased 1% annually until 2010, two-thirds of the potential energy saving in the EU could be achieved. This would comply with 40% of the EU's Kyoto obligation to reduce greenhouse gas emissions by 8% on the 1990 level by 2010-12, by cutting 200 million tonnes of CO2 emissions per year. Improving energy efficiency in existing buildings is often considered to be one of the most cost-effective ways of cutting carbon emissions. Current policy measures, however, seem to be decided with little reference to the specific needs of renovation in the housing sector instead of basing policy measures on detailed sets of requirements and actual costs. The research provides information for national governments in the EU on how to improve their sustainable building policies so as to increase carbon reductions in the existing housing stock. It addresses the question of the extent to which stronger government intervention is possible and necessary for circumnavigating barriers and the policy approaches that are likely to be feasible, effective, cost-efficient and legitimate.
Sloop en sloopmotieven, tussenrapportage enquête sociale huursector
- A Thomsen
- M T Andeweg Van Battum
Thomsen, A. & Andeweg van Battum, M.T. (2004), Sloop en sloopmotieven,
tussenrapportage enquête sociale huursector. Delft (TU Delft).