Adopting a circular vision in the construction industry

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Adopting a circular vision in the construction industry

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Master Thesis

International Master of Science in Construction and Real Estate Management Joint Study Programme of Metropolia UAS and HTW Berlin

Faculty 2

from

Laurentiu Sebastian Hategan

s0567941

Date:

Berlin, 31.10.2020

1st Supervisor: Prof. Dr.-Ing. Dieter Bunte

2nd Supervisor: Principal Lecturer Hannu Hakkarainen

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Acknowledgements

I would like to express my gratitude towards my supervisors, Principal Lecturer Hannu Hakkarainen and Prof. Dr.-ing. Dieter Bunte, for the much-needed feedback and support during the writing process of this thesis.

Thank you to my dear colleagues that have made these very intense academic years more enjoyable.

And finally, I would like to thank my family and Maria Speeti for their love and support.

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Abstract

Over the past decade topics concerning the climate and how to preserve it have become increasingly relevant. Due to its make-use-dispose mentality as well as the slow adaptation of new technologies, the construction sector forms one of the worst climate polluters, waste producers as well as natural resource extractors. This thesis will offer alternative methods of construction which will allow the sector to change its course to a more circular, make-use-reuse, direction. These methods will be presented and evaluated according to their advantages, disadvantages as well as financial aspects. The data for this research is collected through a complex literature review offering insight on various circular concepts as well as presenting case studies which showcase different methods in practice.

The thesis begins by discussing the current methods utilised in construction today and the possible sustainability challenges related to them. This is followed by introducing the concept of circularity and assessing its compatibility with the building sector. Some possible techniques for adding circularity into construction will be presented along with relevant case studies. In total, five cases concerning four different circular methods, design for disassembly, usage of recycled building materials, building repurposing and material passports, will be brought forward.

After assessing the information included in this research, it can be stated that there are multiple ways of increasing circularity in construction and all of the methods presented lead to numerous environmental benefits, such as minimisation of waste production and natural resource exploitation. The concepts still require further developments and possible endorsement from the officials in order to push them into new standards in the construction business.

Keywords: circularity, circular economy, material passports, building repurposing, design for disassembly, recycled materials

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Table of Figures

Fig. 1: The take-make-dispose system ... 3

Fig. 2: Estimated remaining world supplies of non-renewable resources ... 4

Fig. 3: Country Overshoot Days 2020 ... 8

Fig. 4: Methods of introducing Circular Economy in the construction sector ... 10

Fig. 5: Different aspects between Linear Economy and Circular Economy ... 12

Fig. 6: The proposed circularity applied to the construction sphere ... 13

Fig. 7: The different layers of a building ... 19

Fig. 8: Two alternative solutions for the building’s end of life ... 21

Fig. 9: A comparison between the current and adapted lifecycle of a building ... 23

Fig. 10: Illustration of the aerial view of The Four Administrations building ... 25

Fig. 11: Views of different sections of the designed building ... 26

Fig. 12: A sectional view of the façade ... 27

Fig. 13: Different layers and structures used in the building process ... 28

Fig. 14: The figure shows the extent to which the building is utilising standardised elements ... 29

Fig. 15: Various joints and connections between building elements ... 30

Fig. 16: The seven dimensions of a construction ... 31

Fig. 17: The Resource Rows ... 34

Fig. 18: Structure of apartments ... 35

Fig. 19: The resource Rows building with recycled wall modules ... 36

Fig. 20: The steps of assembling upcycled brick walls into modules ... 37

Fig. 21: Muuratsalo Experimental House designed by Alvar Aalto is used as a source of inspiration for the upcycled brick modules ... 38

Fig. 22: A comparison between the environmental impact between new and reused elements ... 39

Fig. 23: The earlier, current and future utilisation of the outdoor area of Tempelhofer Airport. ... 43

Fig. 24: Left the current condition of the old traffic control and right the planned renovation ... 45

Fig. 25: The condition in 2016 (left) and future design plans (right) for the western side of the airport ... 46

Fig. 26: Tegel Airport is built in a hexagonal shape ... 47

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Fig. 27: Visualisation of the future Tegel Airport ... 48

Fig. 28: Planned usage of the Tegel Airport. ... 49

Fig. 29: Screenshot of the BAMB online tool ... 53

Fig. 30: Material Passports compared to the Building's Materials Passport ... 54

Fig. 31: The Zollverein Project’s overview page on a material passport... 55

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List of Abbreviations

EU – European Union

EEA – European Environment Agency

€ – Euro

DKK – Danish Krone, the currency of Denmark CO2 – Carbon Dioxide

OECD – Organisation for Economic Co-operation and Development

Gt – Gigaton

CI – Construction Industry CE – Circular Economy

GDP – Gross Domestic Product

C&DW – Construction and Demolition Waste PPP – Public Private Partnership

LCC – Life Cycle Costs

BIM – Building Information Modelling VDC – Virtual Design and Construction HVAC – Heat Ventilation and Air Conditioning

UNESCO. – The United Nations Educational, Scientific and Cultural Organisation

DGNB. – Deutsche Gesellschaft für Nachhaltiges Bauen, in English

“German Sustainable Building Council”

BAMB – Buildings as Material Banks MP – Material Passport

BMP – Building’s Material Passport

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1. Introduction

Over the past decades climate change has become an increasingly discussed topic and with it the role that humanity has concerning it. According to a large number of scientists, it is undoubtedly that humans and our current way of living as well as the industry have had a large negative impact on the climate and on the general wellbeing of the planet. Construction industry forms one enormous part of our today´s world and likewise also a large part of the challenges that plague it. In 2018 the Global Alliance for Buildings and Construction released a report which stated that the construction industry accounts for 40% of the global CO2 emissions and according to the European Environment Agency (EEA) the industry was responsible for 374 million tonnes of waste produced in the EU in 2016 (European Environment Agency, 2020; Global Alliance for Buildings and Construction, 2018). Unfortunately, and accordingly, the industry is also named as the number one consumer of global natural resources. This comes as no surprise when one looks at the construction sector and compares the total amount of new constructions or the renovations performed around the globe with the almost non-existent increase in productivity the sector has seen since the late 19th century. According to a research conducted by McKinley&Company in 2017, the productivity of the construction industry has only increased by 1% per year during the past 20 years. Comparing this to the 2,8% growth per year in the total world economy during the same period, one begins to perceive the immediate need for change and improvement. One possible method to achieve the much-required improvement in productivity could be through circularity. In this way, the growth in construction would also be achieved in a sustainable way and without causing further damage to future generations. In the past 13 years the total population of the world has increased by one billion people and will most likely continue growing at the same rate in the future (United Nations, 2019). If the construction sector keeps causing this amount of harm, both concerning resources, waste as well as general pollution, without improving its productivity, the amount of environmental damage caused by the sector will also proportionally increase along with the population.

One of the proposed solutions to tackle the climate damages caused by the current construction industry is circularity. The case studies presented in this paper are evidence that circularity is slowly finding its way into the construction sector. The

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circular economy itself is an essential way to minimise waste, emissions and the consumption of energy by changing the linear make-use-dispose mentality into a more sustainable circular make-use-reuse one. Applying circular methods and thinking into construction does not only lead to buildings consuming less energy and resources, producing fewer greenhouse gasses but also to better management of waste and more efficient and sustainable utilisation of the resources left on the planet.

How can this substantial negative effect caused by the construction sector on the globe´s health and resources be changed then? This thesis will present the concept of circularity and how it can be implemented in the construction industry in various ways.

It will also focus on identifying and analysing potential compatibility problems that might interfere with the application of circularity in construction. Another topic which will be discussed is the extent circular economy can cause a decrease in both emissions produced as well as resources exploited. Finally, the financial aspects of the circular method in the construction business will be given importance, and it will be discussed if the implementation of such methods will be cost-effective in both short and long term.

The primary method in which these topics will be analysed and researched is through a broad literature review. The literature review will focus on bringing forward different methods of applying circularity in construction along with their challenges and possibilities. In addition, five case studies of varying construction projects will be presented. Through these case studies, four possible ways of introducing circularity will be brought forward. Finally, in conclusion, the above presented research questions will be tackled according to the information and scientific aspects gathered through the extensive literature review as well as the real-life examples gained from the case studies.

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2. Linear Economy and its effects on the environment

Since the beginning of the Industrial Revolution in the 18^th century, the ability to create products in mass has been developed, which in turn resulted in a boost in the economy.

In fact, it helped Europe in becoming a major economic power and its population has enjoyed a considerable increase in GDP per capita since. The type of economy used is called linear economy and revolves around a take-make-dispose system (Figure 1).

This means products are manufactured using raw materials, they are used until the end of their life cycle and then disposed as waste or incinerated while inevitably polluting the atmosphere. (Ellen McArthur Foundation, SUN, McKinsey Center for Business and Environment, 2015)

Fig. 1: The take-make-dispose system. Own work.

As shown in the picture above, linear economy is based on the concept of take-make- dispose where take represents the natural resources extracted, make represents the goods created with the help of natural resources and finally dispose represents the life cycle end of a product that will be discarded.

According to C-Voucher (2019), this type of economy presents several issues which can produce harmful consequences in the near as well as distant future:

- Overproduction. It is common that products are mass-produced and a percentage of them do not get to be sold. This leads to overproduction and unnecessary usage of resources.

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- Shortened life cycles. The accelerated pace on which new products appear, especially in the technological sector, means that only a few years old products become rapidly outdated. The fact that the industry is constantly pushing into producing more new products at a faster pace means that the life cycle of these products is slowly decreasing.

- Waste build-up. Overproduction and reduced life cycles play an important role in the accumulation of waste. Using materials that are non-recyclable or reusable is also an essential factor that has to be taken into account in this type of economy.

- Exhaustion and overutilisation of natural resources. In case the extraction and overutilisation of natural resources continues at this pace, a shortage of resources will follow, and the earth’s regenerative limits will be reached.

As previously mentioned, the linear economy aims more to economic profits rather than sustainability and is also based on the assumption that resources are unlimited. This is unfortunately not the case as, according to BBC (2012), the natural resources are slowly coming to an end (Figure 2).

Fig. 2: Estimated remaining world supplies of non-renewable resources. (BBC, 2012)

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With the previously mentioned information in mind, one must also take into consideration that the reality of a linear economy also varies between different companies, countries, and it has evolved massively over the years. When the industry first boomed in the 18^th century, there was hardly any consideration or knowledge about the limitations of natural resources or the damages of global pollution. Since then the amount of information has significantly increased and with it came a change in the mind-sets of people. In today´s world where recycling and global health are more important than ever, even linear economy has started to adapt and evolve accordingly.

Although nowadays in most developed countries it is almost a standard to recycle waste such as paper, cardboard, glass and metal, it is still not nearly enough, and more factors need to be taken into consideration in order to create a greener future. Although the recycling of some waste materials is a valuable and a good first step, there needs to be a shift also at the beginning of the lifecycle of a product. This means extracting fewer non-renewable resources as well as simultaneously improving and creating new technologies that allow the creation of products which are easier to refurbish, recycle and reuse. As a conclusion, it is fairly clear that even though the linear economy can be approved and made more sustainable, it will not be sufficient. Instead, the global industries should aim to shift their ways of production into a more circular model.

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3. Sustainability challenges in the construction industry

According to the European Commission (2016), the construction sector is responsible for around 9% of the European Union’s (EU´s) GDP and provides around 18 million jobs. The construction sector’s economic activities range from the extraction, manufacturing and transportation of raw materials, designing, building, maintaining, renovation and demolition of buildings and all the way to the recycling of construction and demolition waste (European Commission, 2016). There is no doubt that the construction sector plays a substantial role in both EU’s but also in the world’s economy.

That is not to say that this particular sector is without flaws. On the contrary, the downsides of the construction industry have been long known and are worth discussing. First of all, unlike many other industries, the basic function or structure of the construction industry has barely changed over the past few decades in the sense that it is slow to adopt new technologies (Petrov & Hakimov, 2019). The construction sector is also known to struggle with productivity issues, be it projects that run behind schedule or projects that end up being significantly more expensive than planned. The slow adoption of technology in this sector is, according to a study conducted by Blanco et al. (2018), one of the major reasons behind this productivity dilemma. This industry has also been named as the single biggest waste producer in the EU, producing over 374 million tonnes of waste in the year 2016 (European Environment Agency, 2020).

At the other end of the tunnel, the construction industry is also known as one of the largest resource consumers globally, accounting for nearly 50% of all extracted materials (European Commission, 2014).

After considering these three factors, it comes as no surprise that recycling and circularity in today’s construction world are both poorly developed and not utilised to their full potential. Construction materials and their utilisation are not developed adequately in order to sufficiently reduce the negative effects on the climate caused by the industry. New and improved construction materials are required to enhance sustainability in this sector. As an example, the components used to create Portland Cement have barely changed since the time it was created nearly 160 years ago (Mason & Lea, 2020). According to Andrew (2018), the total cement production accounts for nearly 8% of the global CO2 emissions leaving room for improvement.

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4. The Circular Economy

During the past few decades, it has become clear that the climate is changing and doing so at alarming speeds. It is clear that our ways of living must be changed and improved to at least slow down the climate change process. Sustainability plays an important role in this game. One of today’s issues is the increasing use of resources.

In fact, this issue is so severe that, according to a report released in 2019 by the Organisation for Economic Co-operation and Development, by 2060 the worlds material resource usage will almost double (OECD, 2019). It should come as no surprise that economic growth is responsible for this massive increase. Even though the growth of the economy itself is an almost certainty and mainly a positive fact, the important questions is how it shall be achieved. The non-sustainable way would be to continue using mainly new resources, for example fossil fuels, which will not only be damaging in the extraction process but also in case of processing and disposal of materials. What we should aim for instead is almost 100% reuse of materials, which is also known as circularity. This does not only solve the problem of our limited supply of raw materials but also drastically reduces the total amount of waste and pollution caused by products and materials reaching the end of their lifecycles.

In an article released by OECD, they stated that the global material usage would rise from 89 Gt to 167 Gt between the years 2017 and 2060 if the current material use policies are not changed worldwide. This, in turn, will cause a doubling of greenhouse gas emissions, pollution to all the ecosystems and everything living in them. (OECD, 2019) As stated before, our future should be more focused on changing the current linear economy into a more circular one. This means switching from a make, use, dispose approach to a more sustainable make, use, reuse way.

Furthermore, the Global Footprint Network, an international research organisation has calculated Earth’s Overshoot Day by taking into consideration the countries consumption and Earths capacity of regenerating in one year. (Global Footprint Network, 2020) Figure 3 shows us an idea of how each country performs related to earth’s limitations.

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Fig. 3: Country Overshoot Days 2020. (Global Footprint Network, 2020)

As an example, if the whole world would live like Germany for an entire year, the earth overshoot day would be reached after the 5^th month of the year. While Germany lays somewhere in the middle of this chart, the worst positioned country is Qatar where the overshoot day would already take place at the beginning of February. What Qatar and the other five worst raked countries, Luxembourg excluded, all have in common is their wealth is primarily based on the extraction of fossil fuels. As already previously mentioned, fossil fuels are one of the largest threats when it comes to the health of this planet. Both the extraction as well as the usage of fossil fuels is immensely damaging to the climate and one of the main aspects that the circular economy aims to address.

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4.1 Understanding the Circular Economy

The concept of circular economy, also known as circularity, has become widely popular during the last few years and it promises to solve and improve the world’s sustainability issues. The most recent and most commonly used definition of the circular economy came from the Ellen MacArthur Foundation in 2015, describing it as an “industrial system that is restorative and regenerative by design”. This means it concentrates on maintaining products and materials in use for as long as possible by improving their maintainability, upgradability and durability, thus minimising the need to resort to new products. (The Ellen MacArthur Foundation, 2015) This, on the other hand, aims at reducing the number of new goods produced and thus raw materials extracted, causing a direct positive impact on the environment.

Even though circularity is currently most widely used in the textile industry (Muthu, 2019), multiple other branches of industry are also starting to understand its many benefits, including agriculture, logistics, automotive, furniture and construction.

4.2 Circular economy in the built environment

The circular economy can be applied to the built environment provided that an improvement in the circularity of the materials used in this sector will be performed.

The goal is to reach a level of material characteristics that will allow their usage to be extended and also for them to be reused and repurposed more efficiently. This will result in lower demand for extracting materials and maximisation of finite product life.

The importance of creating a more sustainable built environment and the reason behind it has been discussed in the previous chapters. Nevertheless, it is important to stress that this sector, in particular, has an obligation to reduce the waste as well as usage of energy and resources.

In order to facilitate the circular economy in the construction field, three elements need to be taken into consideration. The cultural norm, the products and materials as well as the knowledge or information required in this sector need to be approached. Figure 4 combines the three elements and illustrate the main factors that need to be changed to reach the goal of circularity in construction.

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Fig. 4: Methods of introducing Circular Economy in the construction sector. Adapted from (Green Building Council Finland, 2018)

Unlearning is one of the most important factors because it is one of the first concepts that need to take place for a fast change. It is a challenging task to alter the current habits and partially relearn the basics of construction. Nevertheless, once this step has been successfully taken, it facilitates the other requirements.

Expertise is required to expand the knowledge and information regarding the ways to further enhance factors such as materials, building techniques and sustainable design.

It is also essential in delivering this new information to current students in order to slowly turn it into the new norm.

Foresight is crucial in every sector and presents a vital ability to predict what the trend will be in the future.

Planning, development and design need to be adapted to develop the sector and increase the sustainability level. It can be applied to developing new materials with better characteristics related to reusability and disassembly. The designing process should also take in consideration the possibility of repurposing a building after the end of its service life.

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Procurement phase should be adapted to the new requirements that are suggested by the circular economy. The procurement of materials and goods with a long life-time or a low environmental impact should have priority to unsustainable materials.

Innovation brings continuous improvement to the current building techniques, materials and designs and is thus an essential component in order to accelerate the change into a more circular future.

Open and shared information is the key to allow other countries access to new technologies and goes hand in hand with the expertise and innovation factors. Only with an open and shared information database can multiple countries reach similar circularity levels simultaneously, thus expanding the positive effect impacted on the planet.

Ownership models play an essential role in the transition to a circular economy.

Adapting them to the construction industry means that the producers of materials should be held responsible for the waste their products generate. One of the producer’s primary objectives should be directed towards improving the design, reducing raw materials and waste, and improving the reusability of products at the end of their life cycle.

Value of materials and labour should be kept reasonable. Even though a price increase is typically expected with every new iteration of a product, this trend should be kept under control by making these new innovative circular materials and technologies readily available, thus allowing more companies to produce or utilise them. This in turn will make the new methods more standardised, thus decreasing their costs.

Life cycle knowledge means understanding the life cycle of a product and endorsing circular economy at each phase of planning. It is an essential step in the transition to a more sustainable building environment.

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4.3 Reality of Circular Economy

Finally, it is worth mentioning that multiple models and illustrations of circularity and circular economy offer an ideal concept which in most cases, cannot be fully accomplished in reality. A more realistic approach is demonstrated in Figure 5.

Fig. 5: Different aspects between Linear Economy and Circular Economy. Adapted from (PBL Netherlands Environmental Assessment Agency, 2019)

Figure 5 does not only illustrate the concept of circular economy as well as its differences between linear economy, but it also shows a more realistic approach of the two opposing models. Even though the linear economy is based on the idea of make- use-dispose, it has been altered through time to adapt to the rising need for sustainability thus also having circular components both concerning renewable as well as non-renewable resources. The basic concept of the linear economy still remains the same but also features some aspects drawn from circularity. Likewise, circularly as a concept can rarely be achieved by 100%. Instead, it will always possess some components of a linear model due to the imminent usage of some materials which simply cannot be recycled and reused out of already existing products. This also applies to the fact that not all materials or products can be reused completely which makes some production of waste material unavoidable. Still, this does not abolish the central idea behind circularity, and that it aims in diminishing the usage of new, non- renewable resources as well as maximising the lifecycle of products and materials. It only depicts a more realistic and realisable approach to the topic rather than offering an ideal but non-achievable goal.

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4.4 Improving management of construction waste and resources

One of the most significant challenges that the construction field needs to tackle is the enormous amount of waste created and, on the other hand, resources exploited.

According to a summary released by the EEA in January 2020, the waste generated in the construction and demolition process accounts for the largest amount of waste produced in the European Union (European Environment Agency, 2020). In the following chapter, we discuss some examples of circular actions which could be utilised to improve management of construction and demolition waste (C&DW). The information is mainly adapted from a briefing released by the EEA, “Construction and demolition waste: Challenges and opportunities in a circular economy” (European Environment Agency, 2020) but also features data collected from other sources, which are sourced separately within the text.

When the aim is to improve the management of C&DW, the attention should not only be focused in the late parts of a product’s life cycle concerning the actual demolition process. Instead, the focus should be stretched to various areas in the product´s or material´s life span (Figure 6).

Fig. 6: The proposed circularity applied to the construction sphere. Adapted from (European Environment Agency, 2020)

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As depicted in Figure 6, the management of construction and demolition waste is a key factor in today’s built environment and plays a significant role in achieving circularity.

Furthermore, all stages of a building should be taken into consideration. This includes the sorting of raw materials, the design process, the construction itself, the usage of a building and the end of its life. The end-of-life of a building can be perceived as a new beginning for another building by improving the recyclability of materials. The following pages will explain how all these stages can be enhanced and the possible obstacles that need to be overcome.

Selection of raw materials

The first step which should be taken into consideration is already at the moment of choosing raw materials to use in production. If the construction industry would utilise higher quality products produced from recycled materials rather than using only new virgin resources not only would they directly prolong the recycled material´s life span, thus minimising the waste produced by it, but also reduce the amount of raw materials extracted from the limited natural resources. In addition, this would also create a greater demand for recycled materials in the industry thus causing a positive pressure to increase the quality of recycling on demolition sites since the old materials extracted would not only be considered as waste but rather as possible income sources. At the moment the most significant challenges about this step are the inconvenient price gap between the cheaper virgin materials and the more expensive recycled materials as well as the still-existing doubts about the quality and endurance of recycled materials.

These doubts concerning the quality, in turn, derive from the lack of official standards regarding recycled construction materials.

Another approach when aiming at making constructions more environmentally friendly is to utilise bio-based materials over non-renewable ones. This was also mentioned in a report released by ING Economics Department (2017) where they graded the use of biodegradable materials, for example wood, as having a high level of circularity. What also contributes to the positive aspects of using biomaterials is that they are most of the time reasonably inexhaustible, meaning that since they are a renewable source, they cannot be overused as long as the consumption stays somewhat within limits.

Another great feature regarding the usage of bio-renewable materials in construction is that they can be utilised both in entirely new constructions but also during renovations on already existing buildings. (ING Economics Department, 2017)

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Choosing the right design

The next step where the amount of waste produced can be affected is during the design process of the products which will later be used for construction. Designing products that can later on, during the demolition process, be easily disassembled allows these products to be more efficiently re-utilised, reassembled and recycled in other buildings or construction sites. This is a crucial step towards circularity and allows the goods to be reused easier compared to other products which are not designed accordingly and often become unusable during the tear-down process, thus ending up as waste instead.

Despite this step being maybe one of the most crucial parts of circularity, it also presents multiple challenges that require further researching and planning. Currently, one of the biggest challenges for disassembly-friendly design is indeed purely the lack of knowledge and information surrounding it. Another problem concerning this topic stems from the fact that the demolishing process of a building is usually one of the easiest and fastest steps in the whole life span of the construction since it does not require that much attention to detail or precise separation of demolition waste.

Designing products for more efficient disassembly, and later reuse, would completely alter the whole process and its complexity. It would require a completely new demolition technique that focuses on sparing the valuable materials as well as collecting and separating them from the residual waste. As mentioned before, at the moment there are no standards or regulations regarding these recycled, second-hand, materials which can potentially lead to some problems concerning their specifications. New products always come with a list of specifications but unfortunately, at the moment, the same is not achieved with older, recycled materials. It is also worth mentioning that the amount of time between the design process of the construction products and their final demolition is typically decades or even centuries due to very long life spans of buildings. This causes uncertainty if the final design is going to function as expected as well as simultaneously demotivating possible stakeholders since the potential profit cannot be attained for an extended period of time.

Material passports

Another possible solution to the waste management problem could be the introduction of material passports which contain essential information related to the building’s different materials, their characteristics as well as their amount. This would, for

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example, allow a more controlled demolition process while preserving the possible valuable materials contained in the building. Combining the individual material passports into a more extensive register that collects data from multiple buildings of a city or even a country would significantly increase material recyclability. These registers, along with individual building material passports, would then play an essential role in the designing process of new buildings and allow the completion of a closed loop in terms of recycling construction materials. However, there are a few downsides to this solution. Even though the information of materials of a soon to be demolished building is valuable and crucial for the circularity and recycling, the concept also requires a significant amount of less useful information concerning buildings that will not be demolished in the near future since the data needs to be collected and stored through the whole long life span of a building. This great amount of data that needs to be stored also brings extra labour hours and ultimately costs with itself.

A similar concept concerning material passports was also mentioned in a report released by ING Economics Department (2017) where the ideas of material banks and resource passports were discussed. In the case of material banks, the main idea is to reutilise some parts of an old building that can no longer be renovated or transformed to other purposes such as building blocks for new constructions. With resource passports, detailed information regarding the amount and type of materials used in a building is presented. This information should be readily available for suppliers, contractors but also demolition companies in case of a dismantling of the structure.

In their book explaining the best practices regarding the usage of material passports, Heinrich & Lang (2019) enlist the main benefits that can be achieved when adopting them into practice. These benefits can be roughly divided into two main categories, the economic and the environmental benefits. Some of the economic benefits are the reduction of material costs, gained through handling resources rather than waste, the preservation of material value over time, the easier handling of supply and demand as well as the improvement of quality, amount and security of materials. Regarding the ecological and environmental aspects, it is to be expected that the implementation of material passports would reduce the CO2 emissions otherwise created by the usage of new materials composed out of freshly harvested raw resources. Furthermore, material passports would also enable more efficient recovery of materials during the demolition phase while simultaneously improving circularity in the designing process of the

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building by facilitating building developers to choose recycled and thus more circular building materials. Finally, it can be stated that material passports are almost crucial in the process of the transforming construction industry from a linear to a circular system.

(Heinrich & Lang, 2019)

An interesting small-scale example of the idea behind material passports is presented by a Danish company called Genbyg. They are a 1998 founded company specialised in recycling building materials and selling of used doors, windows, floors, timber and much more. These goods are recovered from buildings that were demolished or when these materials were replaced with new ones. The materials are then registered on their website along with details regarding their size, type and quantity, and sold to both private and professional customers. (GENBYG.DK, nd) This is an example that could be further improved, upscaled, and adopted in more countries in order to better integrate and standardise the concept of material banks in more markets.

Building life span enhancement

Improving and increasing a building’s life span is a self-explanatory yet crucial element in reducing waste production. By applying thorough maintenance and repairs, the life span of a building can be significantly increased and the need for entirely new constructions delayed. (Othuman Mydin, 2017) Also modifying the basic structure of a building in a way which increases its service life, plays a vital role in avoiding construction waste. For example, altering the character of a building from factory to apartment housing minimises both the time and money used for the demolition of the old building as well as the resources used to build the new apartment building.

Segregation of waste

Lastly, one possible solution for improving the management of construction and demolition waste is to focus on distinguishing different types of materials during the demolition process. Due to the fact that construction materials are sometimes hazardous or mixed with other hazardous substances, it is critical to be able to separate the dangerous components from the safe and reusable ones. Some examples of hazardous waste in the built environment include asbestos, treated timber, contaminated soil, concrete additives and paint.

In the long term, this method could improve both the value and the extent of recyclable elements saved. As a matter of fact, this solution could completely change the way we

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consider construction waste. It will have a positive effect on the environment since fewer materials will end up as waste, and the amount of materials that can be reused will increase. Furthermore, certain countries require taxes for waste disposal and by improving the segregation process between harmful and non-harmful materials the total amount of residual waste, and thus also the amount of taxes paid, can be significantly reduced. However, this solution also comes with a few disadvantages that require further attention. Since hazardous materials are not suited for reuse, and since separating these from the reusable materials is a costly process, there is a need for further improvements concerning the segregation process. New technologies must be considered in order to adjust the operation more financially accessible. Finally, the duration of the process, which momentarily is very lengthy, should be improved because time and costs are directly related to one another.

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5. Design for disassembly

To discuss how to make a concept or an industry more circular and thus environmentally friendly, it is crucial to first understand the basic structure behind the industry in question. In his book, Brand (1995) presented a model of the different layers that form a building. These layers can be called the “shearing layers of change”, or the

“six S’s” and are comprised out of Stuff, Space plans, Services, Skin, Structure and Site (Figure 7). In his book, Brand (1995) brought up that it is essential to understand that a building is composed out of multiple layers, each of them possessing different life expectancies. This translates into the building having different paces of alteration ultimately driving the building into self-damage.

Fig. 7: The different layers of a building. Adapted from (Brand, 1995)

Figure 7 shows Brand’s interpretation of the layers of a building, the concept being as relevant today as when it was created 25 years ago. The six main layers of a building are stuff, space plan, services, skin, structure and site and they are sorted from the shortest to longest life span in a building. The majority of these layers require a focus on adaptability to a new client’s needs but also on the circularity aspects.

Stuff

These consist of the movable elements of a building such as furniture, kitchen

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appliances, lamps, carpet, pictures. They usually have a life span of 0 to 5 years and are thus changed fairly often (GXN and Responsible Assets, 2018). There is room for improvement and variation on how a client perceives these movable elements and their value.

Space plan

This layer consists of the elements that form a building like walls, floors, ceilings. A commercial building can typically change these elements every three years, whereas an ordinary house normally around 30 years (Brand, 1995). There is special attention needed to this layer since occupants’ needs are changing at a fast pace, and the building must possess the ability to adapt to these requirements.

Services

This represents the electrical, mechanical and plumbing systems but also elements such as elevators or escalators. These elements need renovation or replacement typically every 7 to 15 years. Depending on the level of their accessibility and the expenses required for their rehabilitation or reconstruction, some buildings are even demolished when this layer reaches the end of its life span (Brand, 1995). Therefore, services and space plan layers require specific adaptability in order to facilitate easier disassembly, thus making it easier for the total life span of the building to be prolonged.

Skin

Since this represents the façade of the building and the part that comes in contact with the weather, a life cycle of around 30 years is expected. During the building’s life cycle, it is almost a certainty that the façade will undergo a complete renewal or a significant renovation at some point (Guldager Jensen & Sommer, 2018). For this reason, it is crucial that the façade can be easily disassembled when the time for renovation arrives.

Structure

Being the support of a building, the structure’s life is expected to range from 30 to sometimes even 300 years (Brand, 1995). Since these elements have a very long life expectancy, it is vital that they can be dismantled and reused in other buildings in case the original building is deconstructed at some point.

When building for disassembly, a few strategies must be put in place. Looking at the

“six S’s” presented above, we can begin by adding improvements to these six layers.

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Firstly, their durability must be increased and in addition, their ability to be dismantled and reused in other projects. This can be accomplished if we direct our focus on the way different elements are connected. For example, prevent the usage of glue and sealants, and instead use dissolvable binders. Nailing down an element is also not recommended since nails deteriorate an element and thus make them harder to be later reused. Using bolts and screws as an alternative increases the reusage of both the element as well as the screws and bolts. Furthermore, the usage of only a couple of different types of fasteners is beneficial since it accelerates both the assembly as well as the disassembly process and allows fewer tools to be required.

Masonry and the connections used should also be given special attention. Using a standard cement-based mortar in brick walls creates a strong non-breakable bond between bricks and makes them hard to separate from each other in the process of dismantling as it brings damage to the units (Addis, 2012). A much preferable alternative to cement-based mortar is the usage of lime-based mortar which binds the bricks more flexibly together and thus facilitates a much more effortless disassembly (Zhou, et al., 2020).

The basic idea and goal behind building for disassembly is relatively simple and demonstrated in Figure 8.

Fig. 8: Two alternative solutions for the building’s end of life. Own work, sources of the photos used: 1) (Pikist, nd a); 2) (Pikist, nd b) ; 3) (Guldager Jensen & Sommer, 2018); 4) (Seier+seier, 2018) ; 5) (Halling, 2020)

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Figure 8 illustrates the two alternative ways of processing the products and materials produced by a building at the end of its life. The more common way today, unfortunately, is to demolish the building after it has reached the end of its purpose and can no longer be utilised for another function. However, the more environmental way is to disassemble the building in a more controlled protocol. This way products such as windows and doors, some of the whole parts of the building such as parts of the walls and the raw materials such as bricks can be recycled and reutilised for another construction project. This does not only have the obvious environmental benefit of minimising the extraction of new virgin raw materials, but it also benefits economically since the demolition companies do not need to invest as much money into handling the construction waste.

The dismantling processes

The process for dismantling the building should be similar to the construction process (Figure 9). When disassembling a building which has been designed specifically for this purpose, the process itself varies from the normal destruction phase. Instead of only demolishing, the aim turns towards preserving and dismantling. Nowadays a typical demolition process includes dismantling different categories of elements such as windows, doors, facades and HVAC systems in order to leave the core building, mainly consisting of concrete and rebars, free to be demolished. Of course, the elements mentioned above will then be further segregated. After this step, the concrete will then be crushed and separated from the rebars, and the gravel produced will be recycled typically either in new buildings or road infrastructure.

This last step is where the design for disassembly drastically changes course. Instead of crushing the concrete and reusing it as a secondary product, gravel, the elements are designed in such a way that they can be easily disassembled and further used as such. This way, the materials and products preserve their original value and purpose.

For example, a wall does not need to be turned into gravel to be recycled but instead it can be reused while possessing the same functionality.

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Fig. 9: A comparison between the current and adapted lifecycle of a building. Adapted from (Guldager Jensen & Sommer, 2018)

Figure 9 pictures the differences between the main steps of deconstruction. The beginnings of both processes are mostly similar and include the necessary steps of setting up a workplace for the engineers and constructors, freeing the construction site of hazardous elements (lead pipes, asbestos etc.) and clearing the construction of movable objects, leaving only the construction shell left. After this step is where the two concepts start to differ substantially from another. The left side of the image shows within the red box the current demolition plan, which results in materials ending up either as construction waste or as downgraded recycling material. The whole plan begins with a selective demolition where similar types of materials are sorted together in different waste piles. Some of the materials will be reused, but the majority will end up as landfill. After all the other materials are removed, and only the concrete skeleton remains, the building is then demolished by machines or by blasting. The resulting concrete residue will then be crushed into gravel which will be downcycled and further used as for example road construction base material.

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The right side of the picture, within the green box, represents the more modern approach to deconstruction, which most likely will become a standard in the future.

Instead of demolishing the building, it is carefully dismantled into either whole structural elements for example walls, façade or slabs, or into building materials that can be easily recycled. The difference between these dismantled and selectively demolished building materials is that the first one withholds more of the original value and purpose and can thus be more easily reused in a different building.

Finally, the last steps include the removal of construction waste from the site as well as bringing the plot to its original state, for example, by filling the site with soil. The last two steps will most likely remain unchanged also in the future.

5.1 Case study – The Four Administrations, Denmark

The first case study presented is a comprehensive concept of an office building in Copenhagen, Denmark, referred to as The Four Administrations. The following information is mainly collected and summarised from the book “Building a circular future” released in 2016 and republished as a third edition in 2018, as a collaboration between the authors Jensen Guldager and Sommer Kasper, and the Danish Environmental Protection Agency (Guldager Jensen & Sommer, 2018). The project was been designed by 3XN Architects, MT Højgaard, DEAS and Balslev, and it promises to change and enhance the way people think about both circular constructions and designing for disassembly. When approaching such an innovative way of designing and constructing a building, most of the attention is understandably directed to the expenditure aspect. This is an interesting and vital aspect, mainly because the common perception nowadays tends to be that circularity, or environmentalism in general, automatically results in extra costs without any economic benefits. The results of this project seem to speak against this perception since the building and its components are designed in a manner which allows them to produce value at the end of their life cycle when they can be resold and reused as raw material instead of ending up in waste. This relevant aspect has been taken into consideration during this project, and the results go against the common misconception that sustainable choices, although being more ethical, always end up having a negative effect on the budget. One of the reasons why a project such as The Four Administrations was needed, was to offer a real-life model to address the factor of

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uncertainty regarding the expected value when applying a circular approach into the construction sector.

The Four Administrations, illustrated in Figures 10 and 11, is designed to be a turnkey bid project and its existence is to act as an example to future construction projects that want to tackle the idea of circularity as well as sustainability.

Fig. 10: Illustration of the aerial view of The Four Administrations building. (Guldager Jensen & Sommer, 2018)

Since circularity applied in the construction field is a relatively fresh concept, there is a certain risk factor when designing this way. This goes especially for large scale projects such as The Four Administrations. There is a higher risk when designing on a large scale with somewhat new technologies, approaches and even different end goals. This is another relevant reason why a concept like this is beneficial for the industry. A large- scale project creates incentives for construction companies to adopt similar kind of measures not only to large scale but also to smaller-scale projects.

The project has been created in collaboration with the Danish Government and is a Public-Private Partnership (PPP) which means that contractors have not only the responsibility of creating a design and the purpose of a building but also to integrate the operation and maintenance costs for the project over a period of 30 years. This

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move undoubtedly forces contractors and architects to aim their attention not only to the construction costs but also to the Life Cycle Costs (LCC).

Fig. 11: Views of different sections of the designed building. (Guldager Jensen & Sommer, 2018)

The building

The project has a size of around 38.000 m² and a built value of DKK 860 million or € 115,5 million. As mentioned before, the primary design approach was oriented to an easier disassembly at the end of the building’s life cycle. The building was designed to facilitate four main Danish government agencies.

The structure has a load-bearing façade (Figure 12) along with concrete slab elements.

The load-bearing façade facilitates a certain freedom when designing the interior

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offices and openings as it eliminates the need for interior columns. This also enables easy repurposing of floor areas.

Fig. 12: A sectional view of the façade. (Guldager Jensen & Sommer, 2018)

The foundations are built with the help of pillars, and the ground floor is made out of concrete which is cast on site. All the floors are made out of concrete slabs which are impregnated and polished with wax, thus giving them an industrial look but also facilitating cleaning and easy maintenance. Windows are built with wooden and aluminium frames, and between them, composite profiles that have both isolation and

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condensation prevention characteristics are installed. Given the fact that the windows are in contact with the weather, they would have to be changed at some point during the building’s lifetime. For this reason, the frames are built in such a way that they can be easily disassembled when the time comes. The shadings are made from expanded metal and connected to the building’s body through screws rather than welding. Both the floor and roof slabs are made of 400-millimetre prestressed hollow core slabs which lay between the curtain walls. Steel composite beams are attached to facades, individual columns and shaft walls, and support the slabs. The partition walls are built to be movable, allowing the interior space to be adaptable to the client’s needs. The interior side of the external walls has a raw concrete finish that gives it a modern appearance and requires little to no maintenance as supposed to paint, which would need redoing every few years. The exterior walls are plastered with bricks which also require minimal maintenance when appropriately built. They are bound together with lime mortar so the bricks can be easily dismantled and reused. The different layers of the building can be better seen in Figure 13.

Fig. 13: Different layers and structures used in the building process. (Guldager Jensen & Sommer, 2018)

As seen in the illustration above, the ventilation and the cable beds have been designed to be installed in the floors thus further improving the flexibility of the interior space and avoiding protruding elements that might ruin the clean aspect of the room.

In order to design a building that would be effortless to assemble but also to

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disassemble, fast to build and simultaneously cost-effective, the architects at 3XN Architects decided to utilise the method of standardised design (Figure 14). The final project plan included 72% of standardised elements which would allow the project leaders to save both time and money.

Fig. 14: The figure shows the extent to which the building is utilising standardised elements. (Guldager Jensen & Sommer, 2018)

The benefits gained from the standardised elements are manifold. Not only do they save time, and thus money, during the planning and designing process but they also offer an improved alternative to traditional design because they allow faster construction, reduce the time required to train the builders, require fewer different tools and finally enable less variation in design. All of these factors combined contribute positively to the effectiveness of the building process and are thus more economical.

Digitalisation

The usage of digitalisation was necessary to not only help with the designing and construction process but also to improve the recyclability of the building’s components.

Building Information Modelling (BIM) and Virtual Design and Construction (VDC) were the go-to processes utilised in order to reach the circularity goals of the project.

BIM is a well-known tool in the industry, and it is used to improve the construction projects by modelling and digitalising the designs, offering easy three-dimensional

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visualisation of projects and their components. VDC, on the other hand, is a tool that includes information regarding the overall performance of the construction along with milestones and client objectives (Kunz & Fischer, 2020). One of the advantages of implementing VDC in a construction project is the fact that it assists in the progress of collaboration between the architect, construction company and client, thus facilitating a smoother designing process and allowing the early optimisation of the project.

Furthermore, the material characteristics collected and stored by the VDC can be later used as material passports and therefore become crucial during the disassembly and reusage phases. In addition to both of the electronic tools offering improvement and valuable data on their own, they can also be utilised together. The VDC tool enhances BIM by adding extra functionality to the table, such as managing the time schedule during the construction phase as well as adding explicit information needed for maintaining the building for its whole lifetime. It also completes BIM by adding relevant information regarding the types of elements used along with their characteristics.

One of the ways that BIM and VDC were utilised for the project of The Four Administrations was in the design and planning process of the connections and joints between elements. The links were designed in a way that they could be easily dismantled when needed. This meant that traditional joints had to be replaced with mechanical connections consisting of nuts and bolts. Using the two digital tools, an evaluation of the building was made in order to determine the most critical joints and their importance in both assembly and disassembly processes (Figure 15).

Fig. 15: Various joints and connections between building elements. (Guldager Jensen & Sommer, 2018)

Figure 15 illustrates the most frequently used connections between different elements of the building. These elements form the floors, ceilings, walls and columns. The digital

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tools allowed the most critical and frequent areas to be recognised thus allowing more focus to be drawn to them. The main goal in the design process of the joints was to facilitate effortless and speedy attachment as well as detachment.

According to Guldager Jensen & Sommer (2018), in today’s construction sector and BIM, there are seven dimensions that need to be taken into consideration in the design process (Figure 16).

Fig. 16: The seven dimensions of a construction. Adapted from (Guldager Jensen & Sommer, 2018)

Figure 16 is a representation of the current and future BIM dimensions used in the construction sector. The first, second and third dimensions are the usual height, depth and width forming the basic structural measurements as well as a 3D representation model. The fourth dimension is related to time schedule allowing easier visualisation of the progress of construction. The fifth dimension is the integration of costs and quantities into the model. The sixth dimension incorporates relevant information into the model, which will later be necessary for the operation and maintenance of the building. This dimension is also used to ensure the optimal performance of the

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building’s elements and their life cycle but also to give facility managers relevant information regarding the efficient usage of the building. The seventh dimension is, according to Guldager Jensen & Sommer (2018), the implementation of data that allows elements of the building to be reused when needed, be it at the end of the building’s lifetime, during an expansion or during renovation. Furthermore, the reusage of the elements would also mean that the owner, instead of investing for waste disposal, is now able to earn value when the time for deconstruction arrives.

5.2 Findings

Building for disassembly is a construction method that is not only responsible for implementing the newest technology into buildings but also for acknowledging a building’s entire life cycle. This is rarely the case with traditional construction methods where buildings are given the most importance during the construction phase and not necessarily during or at the end of their life span. The project of The Four Administrations was chosen as a case study due to its unique nature of utilising this still relatively modern technique.

Possibly the most unique feature concerning the concept of designing for disassembly is the fact that it allows financial benefits to be gained at the end of a building´s life span. Typically, during this phase, only further expenses are to be expected, such as demolition and waste disposal costs. Although being more costly and time-consuming at the beginning of the construction project, designing the building elements in a way which allows them to be dismantled more efficiently allows the materials to withhold their value and thus be easier reused and resold. This, in turn, leads to both direct profits, gained from the sold materials, as well as savings since less construction waste which needs to be disposed is generated. The method also enhances the sustainability and circularity of the entire project.

Designing the elements to be flexibly taken apart if required also assists other forms of circularity, such as repurposing of the building´s spaces. Since the walls can be built in a fashion which allows them to be moved at will, it requires less effort to alter the character and size of the rooms thus further increasing the life span of the building by making it more adaptable and flexible for different purposes.

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6. Material reutilisation

According to a report by The Foundation Abbé Pierre and Feantsa (2015), one in six dwellings is vacant or unoccupied in Europe. A considerable proportion of those empty houses are bound to be demolished, and this brings tremendous opportunity for material harvesting.

6.1 Case study - The Resource Rows, Denmark

As mentioned earlier, material reutilisation or upcycling is one of the ways how the construction industry can adopt a more circular and greener approach. This case study offers an example of how this can be applied realistically to the current construction methods. The study concentrates on a residential complex called “The Resource Rows” located in Copenhagen, Denmark (Figure 17). The project is a collaboration between the Lendager Group and the Arkitektgruppen. The Lendager Group is an architectural office with a long history and expertise of adopting circular ideas into construction designs (Lendager Group, nd). The Arkitektgruppen or AG Gruppen is a privately-owned Danish company focused on a variety of construction-based services from project development to turnkey contracts (AG Gruppen, nd). Other partners in the process are the developer company NREP and engineering consultant firm MOE.

(Kozminska, 2019)

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Fig. 17: The Resource Rows (Lendager Group, nd)

The building’s characteristics

The construction of the area started in 2015 and was finished in 2019 (Lendager Group, nd). The final residential complex has a total surface area of 9148 m² and consists of a total of 92 residences (Lendager Group, nd). Out these 29 are houses including terraces and 63 are regular apartments (Figure 18) (Arkitekturbilleder, nd).

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Fig. 18: Structure of apartments (Wilson, 2019)

The materials

The Resource Rows offers a fine example of material upcycling and modern solutions to an eco-friendlier construction process. Reducing the CO2 footprint of the building was one of the leading triggers when designing the apartment building complex. This was achieved primarily through collecting a large portion of the material used from recycled sources. For example, the façades are built out of bricks that originate from various places, including the Carlsberg breweries, an old school as well as industrial buildings (Arkitekturbilleder, nd). Since separating the bricks from one another is an impossible task due to the wide usage of cement-based mortar, the architects decided to cut the brick walls into modules instead. These modules of 1x1 metres (Figure 19) were then used for the construction of the façade (The Resource Rows, 2019).

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Fig. 19: The resource Rows building with recycled wall modules. (Gonon, 2019)

The total surface amount of façade that was built using this technique of cut-out brick modules was 3000 m², according to Anders Lendager. (Lendager & Vind, 2018) The steps taken to create the modules can be seen in Figure 20. This includes cutting out the wall parts of 1 m²each, fitting them into a 3 m² mould which was finally cast into concrete. These 3 m² moulds were then anchored on a welded steel frame. Using brackets, the whole element was then anchored to the internal wall and insulation.

Since the components were prefabricated, it allowed the construction process to proceed at a faster pace.

Adopting a circular vision in the construction industry