Blog posts - Recreate

June 12, 2025

Paul-Jonker-Hoffren-Tampere-University-–-kopija.png

Olli Vigren

KTH Royal Institute of Technology: Civil and Architectural Engineering

Stanford University: Center for Integrated Facility Engineering & Scandinavian Consortium for Organizational Research

Industry, scholarly, and policy interest in reusing concrete elements in construction has been on the rise. Reuse of concrete elements involves salvaging these elements from buildings condemned for demolition and reassembling them in new construction projects. This interest is largely driven by concrete’s significant contribution to global CO2 emissions, with reuse serving as an alternative strategy for reducing these emissions. There are ambitions to develop solutions that scale from pilot projects to industrial applications. Would you invest your own money in it?

Given these ambitions, there have been relatively few studies focused directly on economic feasibility. Previous research has mainly explored technical feasibility and value creation within supply chains and ecosystems. However, economic feasibility remains a significant barrier to widespread implementation. Economic feasibility generally means that a proposed solution is financially viable and cost-effective, ensuring that the benefits outweigh the costs.

Therefore, we at KTH developed a framework for analyzing the economic feasibility of concrete element reuse, presented in our research article titled “Assessing the Economic Boundary Conditions for Reusing Precast Concrete Elements in Construction.” The article is currently available by request: vigren@stanford.edu

The framework essentially considers three different value chains: standard demolition of an existing building, constructing a new building from reused concrete elements, and constructing a new building from virgin materials (Figure 1). Specifically, we ask:

Which economic factors influence building owners’ decisions to donate or sell concrete elements for reuse?
Which economic factors influence building buyers’ decisions to choose reuse over virgin materials?
Which economic factors influence the profitability of individual actors within the reuse supply chain and the supply chain as a whole?

These questions represent the key considerations within the industry regarding engagement in reuse activities. Building owners play a central role because they own the buildings and can therefore decide how they are demolished and what materials are used in new buildings.

Figure 1: Supply chain of reusing concrete elements.

We identify cost and profitability drivers and analyze key decisions through the lens of economic theory and cost management perspectives. Evidence suggests that owners of old buildings are likely to already have net positive incentives to pursue reuse activities over demolition. This is good news for reuse! However, these incentives are highly dependent on the country, specific context, and how costs are allocated within the value chain.

Buyers’ decisions regarding new buildings are highly context-dependent, as costs can vary significantly depending on the type of project and its organization. Key costs in concrete element reuse include deconstruction, refurbishment, storage, and transportation, while cost reduction drivers stem from savings on landfill fees, material costs, and production costs. Long-term profitability depends on economies of scale, new markets, and innovation.

Investments can already focus on the most promising opportunities, but systematic data and research on actors, costs, prices, markets, and regulatory impacts are prerequisites for informed investment decision-making. Lack of data and understanding causes uncertainty, which hampers long-term investments in reuse technologies and capacity, such as production facilities and warehouses. Can an investor expect the market for reused concrete elements to grow, and if so, when?

Finally, there is a broader need for economic feasibility studies related to circularity. Research has focused on concepts, organizational models, and technologies, but scaling these in the industry—and thereby achieving real impact—requires investors and concrete facts about money. Therefore, I will continue doing business studies on circularity and sustainability.

by ReCreate project

June 6, 2025

ReCreate blog post series on mapping in WP1

Post 4

Author: Niko Kotkavuo, researcher, Tampere University

To gain a broader perspective on the possibilities of reuse and ease knowledge and technology transfer across borders, one of the goals in the ReCreate project is to gather data on precast systems from various European countries. The work is not limited to the four pilot countries of the project (Finland, Sweden, the Netherlands and Germany), but also includes a selection of eastern EU member states known to have large stocks of precast concrete buildings. Besides residential building systems, the ones used in non-residential construction are of interest as well. This blog post series describes that experience. Please find here Part 1 of the series, which explains the nature of this work and describes the Polish experience, here Part 2, which discusses the Estonian experience, and here Part 3, which depicts the Romanian experience. The current post by researcher Niko Kotkavuo from Tampere University describes the Finnish experience and concludes the series, at least for now.

The Finnish experience

In Finland, post-war structural change, rural flight and resulting urban housing shortage led to high-volume industrialised housing construction beginning in the 1950s and culminating in the so-called ‘crazy years’ of the early 1970s. By the mid-1960s, most large construction companies had developed their own closed (company-specific) large-panel construction systems based on examples from abroad. In the late 1960s, to further cut construction time and costs, the concrete industry joined forces to develop an open system that any factory could produce.

The developed system, BES (short for betonielementtisysteemi, or concrete element system in English), was free to use by all operators in Finland. It soon became the new, widely adopted industry standard. In the early 1980s, it was followed by another open system Runko-BES (Frame-BES) for non-residential construction. While the systems have been updated throughout the years and their use has certainly became more versatile, they are still the basis for precast concrete construction in Finland today.

The wide adoption of BES and Runko-BES present a problem for reviewing the systems used in post-war Finland. Material on the BES systems is widely available and easy to access, and it covers a large portion of the precast concrete building stock in Finland. It is notable, however, that based on Mäkiö et al. (1994) and house construction statistics of central statistical office of Finland, the adoption of BES just missed the so-called ‘crazy years’ of housing construction. From the beginning of 1960s to the peak construction year of 1974, a large stock of buildings was constructed using the previous, closed large-panel systems, that are far less well understood.

Material on the previously used systems is significantly harder to come by, and details on the systems are seemingly forgotten in the existing literature. Thus, a more time-consuming approach of identification of specific housing projects, via literature review and by locating relevant construction drawings in municipal archives, has been used in studying the early systems.

Conclusions

Based on the very different experiences in the countries examined here, it is clear that there is no single approach for the review, which would work regardless of country. The work is, as is typical for archival work, quite reactive. In Poland, a large existing body of literature on the building stock made with large-panel systems could be capitalised on. In Estonia and to a lesser extent in Finland, there is a research gap regarding the composition of the housing stock in terms of precast concrete and system usage. In Romania, a lot of archival material has gone missing in the aftermath of the 1989 revolution which presented challenges, but university libraries provided useful catalogues and design manuals, which offer valuable insight into the country’s prefabricated building systems. A common factor for all four countries is that compared to housing, non-residential precast concrete systems and building stocks are a neglected area of study.

With the mapping of Finnish, Polish, Estonian and Romanian systems now complete we have a better picture of the systems used in each country as well as loads of archival material for later analysis, classification and digitisations of the building systems. This kind of work acts as a basis of future knowledge and technology transfer of the ReCreate learnings to new countries and regions.

References:

Mäkiö, E., Malinen, M., Neuvonen, P., Vikström, K., Mäenpää, R., Saarenpää, J. and Tähti, E. (1994). Kerrostalot 1960-1975 [Blocks of Flats 1960–1975]. Helsinki: Rakennustieto.

Tilastokeskus [Central Statistical Office of Finland]. (1974). Talonrakennustilasto 1971 [House Construction Statistics 1971]. Retrieved from https://urn.fi/URN:ISBN:951-46-0905-0

Tilastokeskus [Central Statistical Office of Finland]. (1975). Talonrakennustilasto 1972 [House Construction Statistics 1972]. Retrieved from http://www.urn.fi/URN:ISBN:951-46-1563-8

Tilastokeskus [Central Statistical Office of Finland]. (1975). Talonrakennustilasto 1973 [House Construction Statistics 1973]. Retrieved from http://www.urn.fi/URN:ISBN:951-46-1811-4

Tilastokeskus [Central Statistical Office of Finland]. (1976). Talonrakennustilasto 1974 [House Construction Statistics 1974]. Retrieved from www.urn.fi/URN:NBN:fi-fe2023013118667

by ReCreate project

May 6, 2025

The division ‘Selective Deconstruction – Building in Existing Contexts’ of ECOSOIL Ost GmbH was founded in 2001 and started with a team of five employees. The focus was on the selective (crane-guided) deconstruction of prefabricated buildings. At that time, demand from housing companies was driven by overcapacity, vacancies and a backlog of renovation work. After 20 years, the business segment has established itself and the customer base has grown to around 60 property developers.

Our customer base is characterised by small and medium-sized towns in central and eastern Germany with job losses or poor infrastructure. Initially, the focus of the projects was on the deconstruction of upper floors and entrance areas. Over the years, the portfolio has been expanded to include deconstruction in an ‘inhabited state’, i.e. with temporary roofs.

In addition to our range of services, we require specialised machinery with specific features, such as special cranes, mini excavators and concrete cutting equipment.

Our team carries out the work while the buildings are still inhabited and works routinely with planners and various trades, in particular roofers, plumbers, carpenters and scaffolders.

Further structural challenges include the confined space and the sometimes very different construction methods with load levels ranging from 0.8 t to 6.3 t per element. The structural challenges are always accompanied by occupational safety for all employees.

We are an important point of contact for housing associations, as we have a pool of experience in deconstruction in conjunction with deconstruction planning and in hazardous substance and waste management. At the same time, the requirements of waste and recycling legislation have changed. For construction site logistics and cooperation with waste disposal companies, this means additional work, in particular due to extensive analyses and pre-sorting of waste in order to keep costs as low as possible and remain competitive.

Our largest and longest construction project was the Kugelbergring in Weißenfels (Saxony-Anhalt, Germany), which took over a year to complete and had a contract volume of €1.6 million.

The ‘Selective Deconstruction – Building in Existing Contexts’ division has initiated a construction conference as an industry meeting place, which has been taking place for over twenty years and is unique in this form. As a result, we came into contact with Prof. Mettke, BTU, and joined the EU project ReCreate as an industrial partner in 2008 with our first project. We have been supporting the EU project ReCreate since 2021. It is being implemented at the Hohenmölsen and Kolkwitz sites.

Our business has always stood for sustainable resource conservation through the long-term preservation of living space – always with the aim of improving the quality of life and the environment of former GDR prefabricated buildings. The EU-wide ReCreate project impressively demonstrates the potential of reusing entire ‘prefabricated panels’ in new functional buildings.

We are currently working with 15 employees on several construction projects in Brandenburg, Saxony, Saxony-Anhalt and Thuringia. In addition to the high-profile issues of housing shortages in metropolitan areas, the central issues of urban development in small and medium-sized towns in eastern Germany remain.

When renovating residential space, the requirements for energy-efficient renovation and barrier-free living are increasing. Today, the focus is on neighbourhoods with short distances, good transport links and sufficient green and recreational areas. The former prefabricated housing estates offer good structural conditions for these requirements.

Over the past 20 years, we have helped to create a liveable residential environment in over 200 projects.

by ReCreate project

April 2, 2025

The Czech experience by Marko Čambor from KTH School of Architecture

The experience of research in the Czech Republic is very rewarding and difficult at the same time. Most of the complications arise from the fact that between 1989 and today, two major events happened. The first was the Velvet Revolution in November 1989 and the dissolution of Czechoslovakia in January 1993. With these great shifts come complications, especially with connecting original publishers and producers to certain documents which were not always well kept.

Constructions in the country were overseen by the Ministry of Construction, which, with Czechoslovakia, was dissolved on 1st January 1993. Competencies of the ministry were divided between the Ministry of Industry and Trade, and the Ministry of Regional Development. This further complicates the issues since there is no clear line to divide the legacy neatly, and so the archival work was not well kept. All this results in an unclear answer when you try to find one place that is keeping these invaluable documents. Most of my research comes from personal collections of people who were working on this development with whom I spoke personally, and from collections of trade chambers which were also given these collections from individuals. Nonetheless, the reward of finding these connections is great in and of itself.

The Czech Republic is a country which is no stranger to topics of prefabrication and large-scale housing development. Over a quarter of all residents in the Czech Republic live in panel housing (27%). In Prague that jumps to 44%.

Ratio of people living in panel housing estates in the Czech Republic by region

Citation: ‘Panelové sídliště: dobré místo k životu? Napoví 6. ročník CHPS’. Sociologický ústav AV ČR, 6 2024; Source.

The development of prefabricated housing comes originally from the small town of Gottwaldov (today’s Zlín). Gottwaldov used to be a very important manufacturing hub for the footwear company Baťa. The company and the city of Gottwaldov were focused on the issue of housing the employees of the company. So then they experimented with different approaches to standardized housing. These experiments were mainly focused on brick constructions since Gottwaldov was already producing large quantities of ceramic bricks to be used in the expansion of factories in the city. The first larger-scale prefabricated construction was developed in Gottwaldov as the G 40 type. This was the first standardized construction system to use reinforced concrete construction panels. From this follows a great legacy of development and innovation. Most of the further development comes from the need of architects to be able to use the system and design buildings more freely and from the requirement of the state apparatus for the nationally organized construction to be as effective as possible. One of the first requirements which was given by the XI. Congress of the Communist Party of Czechoslovakia demanded the construction of 1,200,000 flats by the year 1970. This goal was in the end never fulfilled – all flats built between 1948 and 1989 combined make up 1,2 mil. Units. The development of new and more free and efficient systems was constant. Great emphasis was also put on regional efficiencies. Since most of the development of estates was happening close to either the largest cities or centres of heavy industry, the most abundant materials were usually determined by the type of industry. For example, the north-east of the country was focused on the production of steel, so the most common ingredient for facade panels was slag.

From the previous systems came new families of systems. T 0XB systems, BX0 systems and so on. The biggest shift in further development was the year 1970, which brought new political requirements for any future systems. These new norms were called NKS (Nové konstruční soustavy)/ NCS (New construction systems). These new systems were tasked to accommodate all new requirements of style, modular freedom and efficiency. From these came systems OP.XX, PS XX and VVÚ ETA. Simultaneously with these, the country tried to find new options elsewhere. As a result, we got the systems Larsen-Nielsen, which was the only system brought from a Western country, more accurately Denmark.

Construction of a building, VVÚ-ETA system

Citation: M. Janečková, ‘Konstukční soustavy panelových domů, vývoj, typy, půdorysy’, estav.cz. [Online]; Source.

All this production then culminated in the year 1975, which was the year with the most completed units, 71 350. This is the number we haven’t seen since. Production and construction then slowed somewhat averaging around 55 000 completed units. All changed after November 1989, with the Velvet Revolution. The fall of the government meant that there was no large enough authority to organise and also fund large-scale projects. Housing estates which were started before this time and were still under construction were finished, some as late as 1993.

Construction of Bohnice Estate, Prague circa 1976; Source.

The legacy of these large-scale projects is still very present, and with today’s social understanding of the era in which these projects were created, it remains complicated. A large portion of criticism of the estates was directed at their visual quality. Since the prefabricated panels were prefabricated, they mostly look the same giving the finished state of the estates a large scale of sameness. This gave rise to the movement of beautifying the estates with brightly coloured plasters. Often not improving it very much. This practice has been thankfully abandoned since.

The general focus of contemporary topics of study works more in the realm of the socio-economic sustainability of large-scale housing estates. Nowadays is much more common to talk about urbanism and the public spaces within the estates. One of the topics of today is urban density which is significantly lower than the historical centers of Czech cities. So the question arrises if it is good to promote more density in the estates. The plans that work with densifying the estates usually run into great local opposition. So as of now, the question remains unanswered. Nevertheless, it is good that it is clear the future of the legacy of the previous regime (as many call it) inspires people to engage with questions of future development of their area. These tensions also promote interest in the professional areas of study, which try to present the development in a larger social, political and historical context, with more and more amateurs and professional projects being produced. There are a few large-scale projects which present the construction types in context. As mentioned, most research is interested in studies of larger-scale urbanism. However more detailed research might improve the understanding of the legacy of past industry, which still plays a big role in contemporary cities of the Czech Republic.

by ReCreate project

March 5, 2025

ReCreate blog post series on mapping in WP1

Post 3

Author: Filip-Lucian Neagu, researcher, Tampere University

To gain a broader perspective on the possibilities of reuse and ease knowledge and technology transfer across borders, one of the goals in the ReCreate project is to gather data on precast systems from various European countries. The work is not limited to the four pilot countries of the project (Finland, Sweden, the Netherlands and Germany), but also includes a selection of eastern EU member states known to have large stocks of precast concrete buildings. Beside residential building systems, the ones used in non-residential construction are of interest as well. This blog post series describes that experience. Please find here Part 1 of the series, which explains the nature of this work and describes the Polish experience, and here Part 2, which discusses the Estonian experience. The current blog will depict the Romanian experience, and the series will continue one more post on Finland.

The Romanian experience

Graduate of master’s in architecture Filip Neagu joined the ReCreate research team at Tampere University as a research assistant for a ten-week sprint in the autumn of 2024, with guidance provided by project researcher Niko Kotkavuo, to collect material on the precast building systems of Romania. This blog gives the personal account of his involvement and the challenges he encountered while studying the systems:

Similarly to other former Soviet dominated nations in Eastern Europe, the ‘large panels’ (ro. ‘panouri mari’) apartment buildings in Romania have been wearing a heavy cloak sown with the dark thread of a traumatic past communist regime.

However, several contextual differences ensured an especially unique path for the prefabricated panels’ development within the Romanian bubble. On one hand, their sudden appearance was backed by an unforgiving totalitarian urbanism that had previously wiped up entire settlements to force new space for the ‘large panels’ residential neighborhoods, as well as other representative megalomaniac structures. On the other hand, the high seismic activity in the south-eastern area of the country has imposed, at a structural level, certain reinforcement and binding particularities exclusive to the Romanian ‘large panels’ model. The latter aspect would turn up being shook by the devastating 1977 earthquake that measured 7.4 on the Richter scale, an event that hurried the introduction of even stricter building limitations and regulations.

The national revolution in 1989 against the communist party and the execution of its leader Nicolae Ceaușescu marked a clear ending to the dictatorial chapter and everything it entailed. Eventually, this liberation would also induce a massive drop of any interest in communist-related matters. Unfortunately, this phenomenon highly affected any regard in the handling and caring for the archives of the former institutions, including design institutions like e.g. The Design Institute for Standardized Buildings (IPCT) or The Project-Bucharest Institute (IPB). As a result, tracking the traces left by the archives proved as difficult as expected.

For example, for the last few years, a private operator for archival services in the city of Braila has been meaning to sell the former archives of IPB to Bucharest’s City Hall (PMB), a resource of valuable knowledge that should have normally been sought and reprised long ago by the municipal institution. An equally good source of materials from the IPCT era proved to be the university libraries at UAUIM in Bucharest, as well as UTCN in Cluj-Napoca. Dr. arch. Maria Alexandra Sas, a fellow Romanian researcher, has kindly offered to help with consulting some materials found at the library in Cluj-Napoca.

Some catalogs and dossiers, as well as instructive guides for assembling ‘large panel’ buildings published under the tutelage of the standardized buildings design institutions, have been successfully preserved in the university libraries. Even though the materials found at the libraries were in generally good condition, the IPB archives did not experience the same fate. Before recently settling in Braila, they have been dragged around during the last 34 years, some even developing mold overtime or disintegrating into solitary pages.

‘Large panels’ buildings might presently be one of the most valuable and widespread construction resources in Romania. While researching, I found mine and many of my close friend’s childhood homes’ floor plans, listed as sections or series of IPCT type projects. Since such a large portion of the built environment was constructed in a vigorously short period, more than half a century ago, a new era for intervention is right around the corner. Without a plan B of renovating or reusing this resource, or several back-up plans, millions of people could face a sudden housing crisis. The ‘large panels’ construction had almost unintentionally foretold a future in which reuse can be a sustainable option for architectural longevity.

by ReCreate project

February 17, 2025

The Refurbishing Plan developed by Lagemaat outlines a comprehensive renovation strategy for the Prinsenhof A-building that is being used as a donor building to transform it into the Circular Centre Netherlands (CCN) as the Dutch pilot project.

The plan addresses spatial integration, new site layout, and construction processes in Heerde. Temporary facilities, such as a mock-up and the Inspiration Pavilion, will be built to provide a realistic representation of the final design, to test the construction process and design details, and to allow visitors and stakeholders to explore the site. Additionally, a processing and sawing shed will be established to optimise space and facilitate refurbishment operations. The CCN design incorporates hollow-core slabs and façade elements. The façade elements are categorised into corner and middle elements based on structural application. The refurbishment involves uncovering external finishes and insulation to maintain structural integrity. A repurposed in-site tool will facilitate the processing and sawing of elements. Façade elements were cut, and the front parapets were removed from the structural elements with the saw wire. The parapets are then stored separately and stacked for clear and efficient organisation. Hollow-core slabs will be shortened using specialised equipment. This includes, among other things, cutting the elements using a specially designed setup tailored for shortening the slabs simultaneously. This phase ensures the elements are prepared for reuse without damage and in the same place where the CCN will be assembled.

Materials are managed with appropriate storage space to ensure easy identification and accessibility. This arrangement allows efficient use of logistics and space at the main site. The strategic approach aims to reduce risks, minimise costs, and enhance the overall quality of the project. This plan aims to ensure good practices for sustainable construction and future projects, aligning with the objectives of the ReCreate project.

by ReCreate project

February 13, 2025

The Finnish cluster has completed its first mini pilot in the autumn of 2024. The first batch of reclaimed elements – 25 hollow-core slabs – were reused in a block of flats in Tampere.

The building was built by Skanska for the client, affordable rental housing company A-Kruunu. The elements originate from the Finnish cluster’s deconstruction pilot, in which an office building from the 1980s was deconstructed in Tampere city center during the autumn of 2023. The new building with the reused elements stands in Härmälänranta district, Potkurinkatu street, about 6 km to the South-West from the donor building’s location.

Finnish mini pilot building

’It’s great to take part in a pilot that develops circular construction. The project corresponds to our aim to develop housing construction in Finland. The location in Härmälänranta is also attractive’, explains A-Kruunu’s development manager, Ms. Leena Oiva.

The reclaimed hollow-core slabs were reused as floors above an air-raid shelter, which was most suitable for the elements in this building considering the dimensions of the elements.

’Assembly of the reused elements was easy. It did not differ from using virgin elements. The frame of the building is fully precast, so there is further potential for reuse at the end of life.’ says Mr. Toni Tuomola, regional manager for Skanska, and continues:

’Skanska is committed to a green deal for circular economy. We will focus on reusing construction products by exploiting the learnings from ReCreate. The practical experience acquired from the pilot is therefore highly valuable.’

Reused elements were meticulously quality controlled and factory refurbished

Mini pilot installation

The elements reused in the pilot were quality controlled and factory refurbished in Consolis Parma’s factory in Kangasala, a municipality neighbouring Tampere. The first pilot produced invaluable learnings about the need for environmental permits when refurbishing and reusing elements, as well as quality control and product approval of reclaimed elements.

‘Climate change mitigation is at the heart of our strategy. Our aim is to halve our emissions by 2035. In ReCreate, we are looking into the business possibilities of reused elements and how it could contribute to our portfolio of low-carbon products’, shares Mr. Juha Rämö, technology director for Consolis Parma.

‘In addition to the factory refurbishment, we can contribute such core competencies to reuse projects as product design, storage, inspection, testing, and traceability’, Rämö continues.

Business development manager (refurbishment), Ms. Inari Weijo explains the role of Ramboll Finland:

‘In this mini pilot, we at Ramboll developed designing the refurbishment of the reclaimed elements in collaboration with the factory. We also took care of the site-specific product approval of reused elements towards the authorities.’

She elaborates:

‘We acquired useful learnings how to manage the process. This will come in handy in the next pilots and in expanding Ramboll’s service offerings in the field of reuse.’

Mini pilot floor

New pilots are being negotiated

The Finnish cluster aims to pilot reuse of reclaimed precast concrete in more than one building project. Different kinds of buildings and projects will contribute versatile understanding about the requirements for reuse in different contexts. Real-life pilots help to identify barriers to reuse that must be removed in order for reuse to become mainstream.

‘This mini pilot was a valuable first step towards more widespread reuse’, says ReCreate’s coordinator and the Finnish cluster’s leader, Prof. Satu Huuhka from Tampere University.

ReCreate’s Finnish cluster is formed by Tampere University, Skanska, Consolis Parma, Ramboll Finland, Umacon, LIIKE architects, and the City of Tampere.

by ReCreate project

February 5, 2025

ReCreate blog post series on mapping in WP1

Post 2

Author: Arvi Rahtola, research assistant, Tampere University

To gain a broader perspective on the possibilities of reuse and ease knowledge and technology transfer across borders, one of the goals in the ReCreate project is to gather data on precast systems from various European countries. The work is not limited to the four pilot countries of the project (Finland, Sweden, the Netherlands and Germany), but also includes a selection of eastern EU member states known to have large stocks of precast concrete buildings. Beside residential building systems, the ones used in non-residential construction are of interest as well. This blog post series describes that experience. Please find here Part 1 of the series, which explains the nature of this work and describes the Polish experience. The current blog will discuss the Estonian experience, while the series will continue with Romania and Finland later on.

The Estonian experience

Master’s student of architecture Arvi Rahtola joined the ReCreate research team at Tampere University as a research assistant for a ten-week sprint in the summer of 2024, with guidance provided by project researcher Niko Kotkavuo, to collect material on the precast building systems of Estonia. This blog gives the personal account of his involvement and the challenges he encountered while studying the systems:

Challenges with mapping Estonian Soviet concrete construction systems were mainly related to the country’s rather small size. When country is so small that in most fields everybody knows everybody by name, very few things are written down. As a starting point, the available Estonian sources were mainly blogposts, old news articles, or commercial publications on insulating existing residential buildings. Even though the initial material was narrow, it led me to archives, which turned out to be well organized and easy to access.

Finding enough material didn’t turn out to be a problem. The design bureau responsible for designing most Soviet prefabricated housing left behind a large amount of records. Some type building series had over 200 folders of material to go through. The information I was looking for was hiding in four or five of them. Additionally, some of the archived material had unfortunately deteriorated to the point of uselessness. The main challenge turned out to be locating the relevant files while hoping they were in a usable condition.

Processing the found material ended up being a challenge. Having been part of the Soviet Union, where the main language of state and business was Russian, the found archival material was also written in Russian. During the process of finding material and interpreting the blueprints, I got to extend my vocabulary related to precast concrete construction.

Residential buildings in Soviet Estonia were built by the Union wide ‘type project’ system. This means that the same building could be found in Estonia or Kazakhstan. During all the Soviet period, Estonian prefabricated concrete housing was compiled of only few different Union-wide systems and two ‘homegrown’ ones. Compared to many other nations, everything in these buildings was strictly standardized, which made the review work easier.

An interesting aspect of Estonian elements is the use of ‘silicalcite’ concrete and the use of shale oil ash to replace cement. This was mostly because the concrete industry was already struggling to produce enough cement during the years of reconstruction after the Second World War. By using unorthodox materials, building capacity was increased, when ordinary materials were in short supply.

Most of the reuse knowledge about the pan-Soviet systems like the 1-464, or the 111-121, are also hopefully more widely useful. The former was in use everywhere in the Soviet Union, and the latter was also used in many areas; for one in Kyiv, Ukraine.

by ReCreate project

February 4, 2025

Leena-Aarikka-Stenroos-Mikko-Sairanen-Linnea-Harala-Lauri-Alkki_ReCreate-project_Horizon-2020-1.png

ReCreate blog post series on mapping in WP1

Post 1

Authors: Niko Kotkavuo, researcher & Maria Lomiak, research assistant, Tampere University

In the decades following the Second World War, many countries in Europe faced severe housing shortages. This lead to great efforts to industrialise building construction to reduce the cost and increase the speed of construction. The industrialisation effort manifested in many precast concrete building systems being developed, with various levels of standardisation. They became widely-used especially in multi-family housing construction in the second half of the 20th century.

Many of the systems follow national or regional borders while others have crossed borders. Border crossing has taken place e.g. via licence agreements or more unofficially, when features and details of existing exemplars have been borrowed in newly developed systems. Thus, the systems form an interrelated familial network. However, the fact that existing literature on the history of post-war construction has mostly been written in the local languages and for the audiences of the specific countries, is a challenge for the comparative study of precast systems.

To gain a broader perspective on the possibilities of reuse and ease knowledge and technology transfer across borders, one of the goals in the ReCreate project is to gather data on precast systems from various European countries. The work is not limited to the four pilot countries of the project (Finland, Sweden, the Netherlands and Germany), but also includes a selection of eastern EU member states known to have large stocks of precast concrete buildings. Beside residential building systems, the ones used in non-residential construction are of interest as well. This blog post series describes that experience, starting from Poland in the current post, and continuing with Estonia, Romania, and Finland in the next postings of the series.

The Polish experience

Master’s student of architecture Maria Lomiak joined the ReCreate research team at Tampere University as a research assistants for a ten-week sprint in the summer of 2024, with guidance provided by project researcher Niko Kotkavuo, to collect material on the precast building systems of Poland. This blog gives the personal account of her involvement and the challenges she encountered while studying the systems:

In my hometown, Warsaw, large-panel construction is omnipresent in the cityscape. As a matter of fact, across the whole country, large-panel housing is becoming sort of an icon of the past. Though precast structures in Poland tend to be associated with poor technical performance and imperfections, they continue to serve their purpose, providing housing for almost 12 million people (approx. 1/3 of the population).

The findings on Polish industrialised building systems reveal a complex family tree of systems, with few central systems applied nationwide, and multiple regional systems. After the Second World War, the establishment of the communist regime in Poland led to the strengthening of individual cities and regions. Autonomous research centres and local manufacturers emerged, which resulted in unsuccessful attempts to centralise housing systems (Wojtkun, 2012). Aiming at socio-economic growth, the development of industrial technology focused on efficiency through limiting the number of building systems, but the realities of local conditions necessitated continuous modifications, leading to an increasing number of variations for each of the so-called central systems.

Therefore, the preserved material on Polish industrialised systems is extensive, though scattered across various libraries and archives. These prerequisites and limited time for fieldwork meant that when cataloguing and reviewing the Polish systems, a certain degree of prioritisation had to be done. Nevertheless, tracking down reliable sources was the most rewarding part of the job. Then, organising and translating the collected material was more tedious than I initially thought. Incomplete sets of technical drawings or intricate descriptions were some of the difficulties I encountered. However, a handful of industry-specific manuscripts and articles related to the subject allowed me to create a comprehensive dataset on central systems, which were prioritised during the research work. Archival journal articles provided general parameters of systems, but the differences between systems’ variations were documented poorly.

With that in mind, the potential reuse of prefabricated elements of large-panel Polish housing poses a serious yet achievable challenge. Pre-deconstruction auditing would probably require a better understanding of individual variations of the systems.

Reference:

Wojtkun, G. (2012). ‘Standardy współczesnego mieszkalnictwa’. Przestrzeń i Forma, nr 17, pp. 301–322.

by ReCreate project

January 15, 2025

Arlind Dervishaj, KTH

Concrete is used everywhere—in buildings, cities, and infrastructures. However, due to the large quantities of concrete used worldwide, it contributes to around 8% of global CO2 emissions [1]. While efforts are being made to reduce its carbon footprint, such as by using supplementary cementitious materials, an often overlooked solution is reusing concrete.

The ReCreate project aims to foster a circular economy in the construction industry by reusing precast concrete elements from existing buildings in new construction projects. To support this goal, our study investigated the reuse potential of structural concrete elements, evaluating three key factors: the remaining lifespan of concrete, natural carbonation (ability to reabsorb CO2 over time), and embodied carbon savings achieved by reusing it [2]. Reusing concrete has multiple benefits as it prevents waste, reduces the need for new raw materials, and significantly lowers life cycle CO₂ emissions. However, it is not as straightforward as it looks. The structural integrity of concrete with reinforcing steel can be compromised over the lifetime of buildings, if the right conditions for corrosion emerge, such as from the carbonation of the concrete cover and the presence of moisture at the rebar interface [3].

Circular Construction concept for concrete

Based on established carbonation models, we proposed a digital approach for estimating the remaining service life of concrete elements. The digital workflow also estimates the CO2 uptake from natural carbonation. We tested the workflow on an apartment building with a precast concrete structure, built in Sweden in 1967 during the Million Program. The building was modelled digitally, and material quantities and exposed surface areas of concrete elements were automatically extracted.

Digital workflow and building model

A key aspect of the study was the comparison of carbonation rates specified in the European standard EN 16757:2022 with rates derived from measurements in the ReCreate project and the literature [4,5]. This comparison revealed that the carbonation rates in EN 16757 may be overly conservative and hinder the reuse of concrete elements. We argue that relying on contextual carbonation rates, such as the ones in our evaluation, from a previous condition assessment, and new on-site measurements, is crucial for making informed decisions about concrete reuse. The study also addresses the recent RILEM recommendation on revising carbonation rates in standards like EN 16757 and CEN/TR 17310:2019 [6].

Using carbonation rates from EN 16757:2022, led to the conclusion that most of the precast elements would not be reusable (i.e. carbonated concrete cover and past the initiation phase for service life). The standard assumes a high rate of carbonation for concrete, especially indoors, which reduced the concrete’s remaining service life; concrete cover for indoor elements was expected to carbonate the earliest, 23 years after initial construction. However, when using the contextual carbonation rates derived from the ReCreate project’s investigation and recent literature, all elements were deemed suitable for reuse, with sufficient remaining lifespan. Plaster and other coverings slowed carbonation significantly, extending the service life of concrete. Additionally, carbonated concrete elements can be reused, but further considerations should be made concerning the environment and exposure conditions in the new building. Recommendations from ongoing research in ReCreate are expected for concrete reuse in new buildings.

The study also assessed the CO2 uptake of concrete over its life cycle, including the first service life, a potential storage period prior to reuse, and a second service life when reusing precast elements. The findings indicate that the CO2 uptake estimated using the EN 16757 rates was significantly higher than the estimate based on contextual rates. Additionally, the study demonstrated that the climate benefits of reuse exceeded those of carbonation, which accounted for less than 6% compared to the emissions associated with the production and construction of new precast concrete buildings. This highlights the importance of prioritizing reuse as a key strategy for reducing the climate impact of buildings.

Furthermore, the study investigated the implications of three different allocation methods for assessing the embodied carbon of concrete over two life cycles. The analysis included scenarios with and without carbonation uptake. The results indicated that the Cut-Off method was the most advantageous for reusing the existing building stock, followed by the Distributed approach, while the End-of-Life approach was the least favorable. The study emphasizes that the reuse of existing building stock offers a substantial opportunity for mitigating climate change and fostering a circular built environment.

Comparison of three LCA allocations, over two life cycles

References

[1] Monteiro PJM, Miller SA, Horvath A. Towards sustainable concrete. Nat Mater 2017;16:698–9. https://doi.org/10.1038/nmat4930.

[2] Dervishaj A, Malmqvist T, Silfwerbrand J, Gudmundsson K. A digital workflow for assessing lifespan, carbonation, and embodied carbon of reusing concrete in buildings. Journal of Building Engineering 2024;96:110536. https://doi.org/10.1016/j.jobe.2024.110536.

[3] Angst U, Moro F, Geiker M, Kessler S, Beushausen H, Andrade C, et al. Corrosion of steel in carbonated concrete: mechanisms, practical experience, and research priorities – a critical review by RILEM TC 281-CCC. RILEM Technical Letters 2020;5:85–100. https://doi.org/10.21809/rilemtechlett.2020.127.

[4] European Committee for Standardization (CEN). Sustainability of construction works – Environmental product declarations – Product Category Rules for concrete and concrete elements (EN 16757:2022) 2022. https://www.sis.se/en/produkter/construction-materials-and-building/construction-materials/concrete-and-concrete-products/ss-en-167572022/ (accessed November 26, 2023).

[5] European Committee for Standardization (CEN). Carbonation and CO2 uptake in concrete (CEN/TR 17310:2019) 2019. https://www.sis.se/en/produkter/construction-materials-and-building/construction-materials/concrete-and-concrete-products/sis-centr-173102019/ (accessed September 26, 2022).

[6] Bernal SA, Dhandapani Y, Elakneswaran Y, Gluth GJG, Gruyaert E, Juenger MCG, et al. Report of RILEM TC 281-CCC: A critical review of the standardised testing methods to determine carbonation resistance of concrete. Mater Struct 2024;57:173. https://doi.org/10.1617/s11527-024-02424-9.

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