Renovation of Concrete Panel Buildings by Gabi Kaltenyte

MARCH 26, 2015

RENOVATION OF CONCRETE PANEL BUILDINGS BACHELOR DISSERTATION GABIJA KALTENYTE VIA UNIVERSITY COLLEGE CAMPUS HORSENS

TITLE PAGE Architectural Technology and Construction Management BATCoM

TITLE of DISSERTATION: Renovation of concrete panel buildings CONSULTANT: Steen Fynbo Larsen AUTHOR: Gabija Kaltenyte

Student number: 163645 Date: 26.03.2015

Number of copies: 1 Number of pages: Report only: 22.5 (2400 characters per page) All: 43 pages Number of characters: Report only: 54 008 All: 63 675 Font: Calibri 12

All rights reserved â&#x20AC;&#x201C; no part of this publication may be reproduced without the prior permission of the author. NOTE: This dissertation was completed as part of a Bachelor of Architectural Technology and Construction Management degree course â&#x20AC;&#x201C; no responsibility is taken for any advice, instruction or conclusion given within.

Preface This is a final report for Architectural Technology and Construction Management Bachelor degree in VIA University College Campus Horsens with an elective subject on renovation of concrete panel buildings (more widely known as Panelak or Khrushchyovka). The report has been written based on my research of concrete panel buildings built after World War II in literature, dissertations and articles. The illustrations were taken from different sources in the books and on the internet, as well as pictures taken specifically for this report by Gintaras Kaltenis in Vilnius, Lithuania. The list of the sources can be found in the very end of the report. The research was divided into several steps- gathering of the data, completing a survey and interviews with architects working in the field and relevant countries, analyzing and comparing the data and finally concluding the analysis, which can be found in the last chapter of the report under â&#x20AC;&#x2DC;Conclusionâ&#x20AC;&#x2122;.

Acknowledgements I would like to give my special acknowledgements to my consultant Steen Fynbo Larsen for the help and advices before and while writing this project. Also I would like to thank him for contributing greatly to my knowledge and personal development throughout my studies, and always leading me the correct way in my projects since 4th semester, group work and any issues I have encountered while studying. I am very grateful for the interviews and comments on the topic from architects: Grazina Zilinskiene from Lithuania, Djeniu Kazandjiev from Bulgaria and Henrieta Moravcikova from Slovakia. I would also like to thank my family who has supported me in good and bad times and always believed in me. The last but not least I would like to thank to my friends and colleagues who has become like a family to me and with whom I have shared knowledge and my free time.

Abstract This Bachelor Dissertation focuses on the existing and possible solutions for renovating the prefabricated concrete panel buildings spread widely through whole Europe and built in 19401960â&#x20AC;&#x2122;s. The aim of this dissertation is to find what are the common and alternative ways to renovate and convert the concrete panel buildings, as well as find sustainable solutions and conclude which of the ways is the most efficient. Showing that there are more solutions on converting the so called panelak buildings than insulating them externally without solving the real problems laying in the uncomfortable living conditions of the tenants, unhealthy construction, old sewer systems, no ventilation and relatively small apartments is the main focus of this report. Known ways of re-usage are compared in same scale with alternative solutions in order to determine how efficient each of the way is sustainability wise. This dissertation also considers different opinions on such mass housing problems found in literature and questionnaires held by me. The report proves by using DGNB criteria that external insulation is actually not the most sustainable solution existing, and that there are possible and on-market methods already in use which are far more sustainable and efficient.

Key words Prefabricated concrete panel buildings, mass housing, re-usage of existing buildings, conversion, renovation

Contents Preface.................................................................................................................................. 2 Acknowledgements ............................................................................................................... 2 Abstract ................................................................................................................................ 3 Key words ............................................................................................................................. 3 List of Illustrations ................................................................................................................. 6 List of Figures ........................................................................................................................ 6 1.

Introduction .................................................................................................................. 1 1.1.

Background information ......................................................................................... 1

1.2.

Professional relevance and aims ............................................................................. 2

1.3.

Problem formulation ............................................................................................... 2

1.4.

Delimitation ............................................................................................................ 3

1.5.

Theoretical basis and sources of empirical data ...................................................... 3

1.6.

Choice of methodology and empirical data ............................................................. 3

1.7.

Overall structure and rationalization of the report .................................................. 4

Short history and the buildings now .............................................................................. 5 2.1.

Short history of panelaks ........................................................................................ 5

2.2.

Design and construction.......................................................................................... 6

2.3.

Present day ............................................................................................................. 7

2.4.

Value of the buildings ........................................................................................... 10

Renovation today and alternatives .............................................................................. 11 3.1.

Renovation today and its issues ............................................................................ 11

3.2.

Alternative methods ............................................................................................. 13

3.2.1.

Demolition and re-building ............................................................................ 13

3.2.2.

Full renovation ............................................................................................... 14

3.2.3.

Re-usage of concrete panels. ......................................................................... 17

Implementing sustainability ........................................................................................ 19

Comparison of methods .............................................................................................. 21 5.1.1.

Environmental quality .................................................................................... 21

5.1.2.

Economic quality ............................................................................................ 22

5.1.3.

Sociocultural and functional quality ................................................................... 22

5.1.4.

Technical quality ................................................................................................ 24

5.1.5.

Process quality .................................................................................................. 24

5.1.6.

Site quality ........................................................................................................ 25

5.1.7.

Conclusion ......................................................................................................... 26

Conclusion ................................................................................................................... 27

Bibliography ........................................................................................................................ 29 Used literature .................................................................................................................... 30 Appendix 1. ............................................................................................................................ i Appendix 2. .......................................................................................................................... iv Appendix 3. .......................................................................................................................... vi

List of Illustrations Image 1. Mass housing in Petrzalka, Slovakia. 2014 ............................................................... 1 Image 2. Mass housing in Lazdynai, Lithuania, delfi.lt, 2014 .................................................. 5 Image 3. Lazdynai, kurgyvenu.lt, 2012 ................................................................................... 6 Image 4. Petrzalka, Jaroslav Balik, 2013 ................................................................................. 6 Image 5. Lyulin, monitor.bg, 2013 ......................................................................................... 6 Image 6. Staircase in Lithuania, Gintaras Kaltenis, 2015 ........................................................ 8 Image 7. Staircase in Lithuania, Gintaras Kaltenis, 2015 ........................................................ 8 Image 8. Entrance in Lithuania, Gintaras Kaltenis, 2015 ........................................................ 9 Image 9, Entrance in Lithuania, Gintaras Kaltenis, 2015 ........................................................ 9 Image 10. Trash shaft in Lithuania, Gintaras Kaltenis, 2015 ................................................... 9 Image 11. Polystyrene and mineral wood insulation, paroc.lt.............................................. 12 Image 12. Parking in Lithuania, Kotryna Malikenaite, 2015 ................................................. 14 Image 13. Regular bathroom in Lithuania, Tomas Sviokla, 2015 .......................................... 15 Image 14. Common apartment layout in Eastern Europe, 9 floor building, not changed ..... 15 Image 15. Same apartment after a common renovation done ............................................ 16 Image 16. Re-used panel building in construction and after walls have been rendered, conclus.de, 2005 ................................................................................................................. 17 Image 17. Time lapse, Jan Otakar Fischer, 2006................................................................... 18 Title page: Antanas Papšys. „Vilnius. Turistui apie miestą“, Vilnius, „Mintis“, 1977

List of Figures Figure 1. Biggest issues in panelaks, survey results ................................................................ 7 Figure 2. Cars per capita in LT, SK and BG ............................................................................ 14 Figure 3. Sustainability areas ............................................................................................... 19 Figure 4. DGNB Core Catalog topics used in comparison ..................................................... 20 Figure 5. Environmental quality in DGNB criteria................................................................. 21 Figure 6. Economic quality in DGNB criteria ........................................................................ 22 Figure 7. Sociocultural and functional DGNB criteria. .......................................................... 23 Figure 8. Technical quality criteria by DGNB. ....................................................................... 24 Figure 9. Process quality criteria by DGNB. .......................................................................... 25 Figure 10. Site quality criteria by DGNB. .............................................................................. 26 Figure 11. Final comparison of DGNB criteria ...................................................................... 26

GABIJA KALTENYTE

1. Introduction This dissertation is written as a compulsory 7th semester dissertation in Architectural Technology and Construction Management program at VIA University College Campus Horsens in Denmark, and shows the opportunities and challenges in renovation of post war mass housing in Europe. Thousands of generations have lived in this planet, and have been building houses, churches and work places for thousands of years. In a nowadays world, where technology and industry, together with architecture is evolving faster than ever, we are keen to build bigger and better than our ancestors. Most of the buildings which are still standing are considered our heritage, except one particular type of building- prefabricated concrete panel building. Short on money and time, governments have built thousands of these houses throughout whole Europe, mostly Eastern, hoping to demolish them in 15 or 20 years, but we can still see them standing and being occupied by hundreds of families. In this report I want to describe the solutions the governments and architects are using to adjust these buildings to nowadays world, research what else could be done, keeping sustainability and tenant satisfaction as the main focus. To conclude the report, efficiency of these ways will be compared in order to find out which solutions are the best for the brighter future of our cities. 1.1.

Background information

The topic of re-using concrete panel buildings, built in 1940-1980â&#x20AC;&#x2122;s is very common nowadays, since the construction has improved significantly in the last 20 years yet we are left with huge mass housing from Socialism times covering big areas in capitals and small cities. Spreading from high life quality countries such as Sweden and Germany to more poor countries in the Eastern Europe, the so called panelaks are defined as depressing, not humane and worth demolishing. Having lived and experienced life in such buildings, I

Image 1. Mass housing in Petrzalka, Slovakia. 2014

GABIJA KALTENYTE became very interested in this subject. Personally I have been interested in urban housing for several years, therefore have always been stopping in mass housing neighborhoods while travelling. It has been a shocking experience to see people living in such poor conditions, where building regulations and humane living surroundings havenâ&#x20AC;&#x2122;t been improved since the very first day it was built. I have decided to choose this topic as my dissertation after living in Bratislava for half a year and experiencing Petrzalka by living there myself. Petrzalka is the most densely populated residential district in Central Europe, endless jungle of prefabricated concrete element buildings, a place where playgrounds are made of concrete and half of the balconies have been fallen down due to a lack of maintenance throughout the years, a place which leaves you with nothing else but sadness and urgent need to change something. Therefore the main aim of my dissertation is to reconsider the buildings and find the answer to the questionwhat are the different ways to re-use these buildings are and how efficient are they? In order to answer this question, I will research the ways each country is re-using these houses, from external renovation to demolition and compare them in the same scale including u-values, tenant satisfaction, architectural value and etc. Also, consultations and opinions from tenants, architects and engineers will be added to the dissertation, but all researches and conclusions will be done by me. 1.2.

Professional relevance and aims

The problem of old, concrete panel neighborhoods is very well known in most of the countries in the world. Nowadays building density is raising rapidly, and soon there will be no place to build in the cities. Big cities such as Moscow and Berlin have already realized this problem and started demolishing such buildings, taking over whole neighborhoods, costing a fortune to heat up and maintain and being very uncomfortable for families to live in. More countries would follow this example if not the biggest problem- being a mass housing, each house of such kind can support up to a thousand tenants and there is no place for them to move during the construction. As a construction architect, I have noticed that more and more companies are concentrating on renovation of older buildings, not erection of new because of the lack of space in the cities we are facing now. Therefore I find this topic extremely relative to all building industry, always looking for new ways to improve. 1.3.

Problem formulation

Renovation of old buildings has a long history behind, together with government ensuring that only not architecturally valuable buildings are being demolished. Every baroque or gothic building usually causes a lot of discussions about its values between architects and historians, differently than concrete panel buildings, also known as Khrushchyovka (named after Nikita Khrushchev, who has been in charge at the time of their first appearances in Russia) since the only reason they are still standing is hundreds of tenants living in each of them with no place and funds to move. The general renovation of these buildings until now has mostly been external insulation, making it a little less expensive to maintain. With 2

GABIJA KALTENYTE sustainability following most of the new projects, these concrete panel houses are begging for a change and a more sustainable, efficient solution. With that in mind, it would be possible for these buildings not to only be a mass housing, but also allow the tenants to enjoy their homes and benefit from the renovation or conversion of the building. There have been quite a number of projects carried out in a small scale, not using the classical way of renovation, and that raises the questions I will use for my research: -

What are the most efficient ways to renovate or re-use the concrete panel houses and are they worth renovating?

Followed by relevant secondary research questions: -

What are the most common renovation solutions and what could be the alternatives? How could sustainability be implemented in such projects in a holistic point of view? What would be the most efficient and beneficial solution in terms of sustainability?

1.4.

Delimitation

This dissertation will not consider countries outside of Europe and will concentrate on Eastern European countries, mainly Lithuania, Slovakia and Bulgaria. The analysis will only include buildings built between 1960â&#x20AC;&#x2122;s and 1980â&#x20AC;&#x2122;s. All solutions suggested will be possible with nowadays technology. 1.5.

Theoretical basis and sources of empirical data

I will collect the data from literature, journal articles, websites and interviews as well as tutorial information on construction. Most of the information will be based on Lithuania, Slovakia and Bulgaria, because these are 3 countries in Eastern Europe with a significant amount of the panel buildings and are from different regions in Eastern Europe. For more opinions on my analysis I will also conclude a survey with 10 questions, which can be found in the Appendix 1 and an interview with certified architects from Lithuania and Bulgaria. Sustainability standards, such as LEEDâ&#x20AC;&#x2122;s and DGNB criteria will be considered as basis for sustainability measurements. 1.6.

Choice of methodology and empirical data

This dissertation is written using mostly secondary research and data from relevant literature, together with my own observations, answers from architects from Lithuania and Bulgaria. The dissertation also includes analysis of survey answers. The report also contains quantitative data and qualitative data.

GABIJA KALTENYTE 1.7.

Overall structure and rationalization of the report

This dissertation is based on usual Bachelor Dissertation structure which includes introduction, main section with analysis and conclusion. I will consider different solutions in order to conclude the dissertation, including considering opinions and solutions given in found literature. All bibliography and references can be found in the very end of the dissertation.

GABIJA KALTENYTE

2. Short history and the buildings now 2.1.

Short history of panelaks The result was one of the most depressing collections of banality in the history of Czech architecture, one that still marks the architectural landscape of this small country and will be difficult—if not impossible—to erase from its map for decades, if not centuries. 1

More than 20 years have passed after the Communist fall in Europe and most of the countries had taken the opportunity to get back their national identities and hide the reminders of war and occupation times. As important as it is for every nation to get back their history, folklore and freedom, the architecture plays a big role as well. Before the Communist times, every country had had their own style or adaptation of architecture, technology of building and most importantly, their own ‘face of the country and cities’. After the World War II most of the countries, especially in the Eastern Europe had faced huge economic crisis and mass housing problems. Russian architects and engineers had a great solution for this problem- prefabricated concrete mass housing, which offered fast and easy construction for a big amount of tenants, and most importantly- it was so much cheaper to erect than any other building at that time. Millions of such buildings had been placed all over the past communist countries- from city centers to entire neighborhoods in the suburbs and even in the villages. Since a limited amount of versions of panelaks has been used for design, the cities had started to lose their faces and look alike, all grey and

Image 2. Mass housing in Lazdynai, Lithuania, delfi.lt, 2014

Dluhosch, E. 1932

GABIJA KALTENYTE in lack of any exterior detailing 2 . Endless usage of concrete in buildings, pavements, children playgrounds and even parks still stands as a very strong reminder of the oppression times. 2.2.

Design and construction

Housing was a big issue back in the post-war former Soviet Union, more and more people migrated to the big cities during the crisis to search for jobs, and therefore there was a huge demand for housing. According to United Nations statistics, only 54% of people of Czech population lived in urban areas in 1950’s, and by 1980’s it increased to 75%, which shows just how big and drastic the urbanistic change was 3. This drastic change lead to drastic decisions- it was decided to start designing prefabricated concrete panel buildings with no architectural details, no insulation, cheap materials and as minimum space as possible. All former so called Union Republics hired few architects per city to work on master plans and designs of the buildings, therefore most of the designs vary from one neighborhood to another, but since all of them had to be built from concrete and in modular system, most of them still look quite same, here are examples of panelaks:

Image 4. Lazdynai, kurgyvenu.lt, 2012Image 3. Petrzalka, Jaroslav Balik,Image 5. Lyulin, monitor.bg, 2013 2013

The first picture is of a 5 story building in Lazdynai, Vilnius, Lithuania. The neighborhood has gotten Lenin’s award for master planning. Second picture is from Petržalka, Bratislava, Slovakia- the most densely populated area in Central Europe. The last picture is from Lyulin, Sofia, Bulgaria. It is the largest residential living complex in the capital and is known as ‘concrete jungle’. It is not hard to notice that all three examples are looking very similar and shares same design and constructional principles.

More information- “Manufacturing a socialist modernity. Housing in Czechoslovakia 1945-1960”, Zarecor K., 2011 3 United Nations, 2010

GABIJA KALTENYTE

2.3.

Present day

Prefabrication is very popular these days, and concrete panel buildings are the ancestors of nowadays prefabrication. These were one of the first attempts to build houses with such speed, preparing the building elements in factories and just stacking them on top of each other in the site. Since the main reason for such building technology was lack of time and money, we can easily see that it had brought up some big problems for the tenants. In my concluded survey of 75 participants where 48 of them were from Lithuania (43.75%), Slovakia (22.92%) and Bulgaria (33.33%) and 27 were from Spain, Estonia, Italy, Latvia, Poland, Czech, Germany, Denmark, Moldova, Greece, Romania and Iceland, all 64.38% said that the overall conditions in these buildings are not satisfying from the view of the tenants. (Full survey can be found in the Appendix 1).

Biggest issues in panelaks Handicap conditions

44.07%

Fire regulation issues

27.12%

Sound insulation issues

67.80%

Bills

35.59%

Overall condition of the buiding

40.98%

Apartment planning

49.15%

Ventilation issues

38.98%

Amount of people per sq. meter Sanitary conditions

28.81% 16.95%

Master planning 0.00%

38.98% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00%

Figure 1. Biggest issues in panelaks, survey results

The table on the top shows which issues participants of the survey saw as the biggest ones and the ones which should be solved with highest priority. More pictures taken from such buildings can be found in Appendix 2.

GABIJA KALTENYTE Handicap conditions, 45% agreed. Almost all buildings have ground floor half floor higher than the ground floor, therefore all entrances do not have free level access and there are some stairs before the elevator, sometimes even more than 10. Moreover, most of the apartments have steps between rooms, unequal floor to the balcony and so on. That eliminates a possibility of handicap people living in these buildings and creates a big problem for elderly people overall.

Image 7. Staircase in Lithuania, GintarasImage 6. Staircase in Lithuania, Gintaras Kaltenis, 2015 Kaltenis, 2015

Fire regulation issues, 27% agreed. It is widely known that fire regulations hasnâ&#x20AC;&#x2122;t always been a priority, and even though the buildings are made out of concrete and should stand the test of fire, usually it proves differently. Panelaks do not comply any logical fire regulations, windows are very close to each other, there is no fire walls between floors and apartments, usually the whole entrance has only one exit staircase and there are no regulations for having fire extinguishers, hoses or sprinklers. None of the buildings are even equipped with any fire or smoke alarms. Therefore whenever one apartments gets on fire, usually all the surrounding apartments shares the smoke and flames. Sound insulation issues, 68% agreed. Panelaks were built using only concrete and reinforcement, no insulation between or inside of the panels. Biggest issues in this topic are walls, floors and even pipes without the applied insulation. Every step, every dropped toy or conversation can be heard in all the surrounding apartments. Bills, 36% agreed. One of the most important problems when it comes to these buildings are heating expenses. No insulation, a lot of thermal bridges and low maintenance of the buildings created conditions where the building gets easily overheated during summers and cold during winters. In some of the countries bills for heating during cold season exceeds salaries and pensions therefore these buildings are incredibly unsustainable and uncomfortable to live in.

GABIJA KALTENYTE Overall condition of the building, 41% agreed. Maintenance of the buildings in Eastern Europe hardly exists, and that is the main reason why most of the panel buildings are in such a horrible condition. Corrosion, poor quality of concrete and no fixing led to falling balconies, damaged facades and leaking roofs.

Image 8, Entrance in Lithuania, Gintaras Kaltenis, Image 9. Entrance in Lithuania, Gintaras Kaltenis, 2015 2015

Apartment planning, 49% agreed. Most of the apartment has a lot of daylight and not a bad planning, but most of them become very uncomfortable for families because of the limited area. Kitchens as small as 5 square meters, hallways so small two people cannot walk through creates a lot of problems for families with children. Ventilation issues, 39% agreed. None of the panelak buildings has installed ventilation. The only ventilation which exists is either air conditioner hanged outside of the external walls or ducts made afterwards for exhaustion in the kitchen and bathroom which goes straight to outside. Amount of people per square meters, 29% agreed. During the former Soviet Union times apartments were given as a reward for people in high positions and all families had to wait in a waiting list to get one. This created a problem that a lot of families were in the waiting list, therefore they had to move in with their parents to their apartments or the other way around. This issue continued during all years and most of the apartments became homes to grandparents, parents and their children. Sanitary conditions, 17% agreed. Garbage shafts is a common thing used back then and even nowadays in order to make it Image 10. Trash shaft in more easy for tenants to get rid of the trash. But no Lithuania, Gintaras Kaltenis, maintenance and no ventilation made the shafts smelly, dirty 2015 and hard to clean. The other problem most of these buildings shares is insects or even rats- a lot of tenants have issues with 9

GABIJA KALTENYTE cockroaches, rats in the basements due to trash shafts and cracks in the walls and floors which lets the insects to travel from one apartment to another, therefore having one apartment infected affects whole building. Master planning, 39% agreed. In 1980’s cars were a rare thing to have in former Soviet bloc, therefore the master planning went according to that- parking spaces for the buildings are extremely limited and narrow, not fitting nearly half the cars it should nowadays. In Petrzalka, Bratislava tenants are leaving the cars with no hand break on so when they block someone else’s car in the parking, the other person can push it and take their car. Other issue is lack of social areas where people could communicate and enjoy the nature, because most of the areas and children playgrounds are made out of concrete. These are the most common issues found in prefabricated concrete panel buildings, but not all buildings share these and some have different problems. All in all, even 65% of all people questioned have agreed that the overall conditions in these buildings are not satisfying from the tenants point of view, meaning that more than half people actually has a very negative opinion about living in such mass housing, and no one can blame them for not wanting to live in a small, depressing looking mass housing with no architectural face or value. This shows just how big the issue is, considering that most of the families and elderly people in Eastern Europe do live in such mass housing, mostly because they provide cheaper alternative than new constructed buildings. 2.4.

Value of the buildings

Every building ever built has always been seen differently in different architect’s and societies eyes, especially when critics are from different countries, generations and has a very different mindset. Interestingly enough, most of the architects do agree on one thingprefabricated concrete panel buildings do not have architectural value worth preserving. In order to know certified architect’s opinions from three different countries I am concentrating on- Lithuania and Bulgaria on prefabricated concrete mass housing I have interviewed engineer architects. When it comes to panel mass housing or panelki, both architects- Grazina Zilinskiene and Djeniu Kazandjiev agreed that the buildings are undesirable in the society and could be not treated as any form of art since every building is the same and has no authenticity of design, which eliminates the historical and architectural value. The importance of the buildings is existing, but only as a mass housing of the specific historical time and the amount of them in the cities, shaping the suburban areas. When it comes to demolition or renovation of the buildings, G. Zilinskiene stated that demolishing the buildings would be a good idea architecturally, but economically hard to implement because of the ownership rights and the existing tenants. D. Kazandjiev agrees that renovation and refurbishment would be very sufficient. Also by G. Zilinskiene’s opinion, the houses constructed now are built very fast and with no better quality, and 10

GABIJA KALTENYTE that is the main reason she agrees to full renovation, as long as the structure of the building is strengthened and energy loss is taken care of. Re-usage of concrete panels for new buildings got a different opinion though- D. Kazandjiev says that it would most probably not work in a country like Bulgaria, and G. Zilinskiene thinks that it might be way too expensive. Also that the materials and demands now are way more evolved than the ones in 1950â&#x20AC;&#x2122;s, and this is why the best way to re-use the buildings is to recycle the concrete. To conclude the interviews, it is clear that architectâ&#x20AC;&#x2122;s opinions towards panel buildings are almost the same as societies- the buildings have no architectural or historical value, and should be taken care of in a matter of sustainability and re-usage, and if possible, renovated fully, not only externally. Full interviews can be found in the Appendix 3.

3. Renovation today and alternatives In the concluded survey, even 55% of the people who has participated had an opinion that economically talking the buildings are insufficient. This leads to the conclusion that the society is already interested in having their houses as sufficient and economically and sustainably advantageous, which is a very positive fact in this rather saddening research. When asked if the participants would buy an apartment in one of the panelaks, 27% said that under no circumstances they would buy or live in one, 8% agreed that they would move into a externally renovated one, and all 60% stated that they would buy an apartment in such mass housing, if the houses were renovated fully. This concludes that most of young people do not mind the houses and its history, as long as the buildings are changed and renovated to fulfill the building demands and satisfy the logical tenant needs. This chapter describes most common practices of renovating a panel building which is mostly external, and also lists alternative options which are already on the market. 3.1.

Renovation today and its issues

Renovation has gone a very long way in terms of speed, costs and quality during the past 20 years. Most of our cities has been established very long ago, therefore most of the constructional companies are concentrating on the renovation of the older buildings, making them more energy efficient and more comfortable for people to live or work in rather than erecting new ones. Most of the old buildings asks no questions about its preservation due to its architectural and historical value and the municipalities do not let any changes be made on them, except stabilizing the structure and renewing the exterior. But concrete panel buildings rises very different opinions- most of the people would like to see them either refurbished completely or demolished due to its low architectural value and depressing looks. Biggest problem we are facing nowadays with panelaks is the amounts of energy needed to heat them up during winters, and the temperature in colder seasons in the area can easily go under -15 degrees. The solution for this problem has been found long ago- adding 11

GABIJA KALTENYTE an insulation layer on the external parts of the walls and by doing so also â&#x20AC;&#x2DC;closingâ&#x20AC;&#x2122; all gaps and holes which might have been left there or appeared during the years of no maintenance. Most of the companies also repaint the building afterwards, so the problem should be solved- the building is warmer, the cold bridges are minimized and the building looks like new multistory dwelling, painted in cheerful colors. But is this the full truth? Renovating the building externally solves one of the biggest issue noticeable to each tenant- heat loss. Even though it is a good step towards more sustainable housing and decreasing the amount of energy wasted, most of the problems are left unsolved because most of them lie inside, not outside of the building. There are two different ways used for exterior renovation of such buildings- polystyrene insulation and mineral wood. Most of the companies use polystyrene because it is a cheaper solution because the material is cheaper itself as well as mounting is easier, cutting down the construction costs too. There are more minuses of polystyrene than pluses- polystyrene is very flammable, has a low resistance to moisture and therefore these conditions of constructions escalate issues such as condensation and mold growth which affects indoor air quality. A lot of tenants have complained that external renovation created very good conditions for mold to grow in their apartments due to lack of ventilation, because buildings have been built with a lot of thermal bridges which have let out all the moisture out during the years before the renovations4. After adding the insulation and changing the windows the apartments got sealed and no Image 11. Polystyrene and mineral moisture could get out, and it would be okay in nowadays wood insulation, paroc.lt houses with ventilation, but since no ventilation has been added and none exists in the buildings, mold started to grow around windows and on ceilings on the last floors. Mineral wood, on the other hand, is not flammable, does not grow mold and is chemically neutral, which is way better for a building and tenants living there, but is around 30% more expensive than polystyrene, and that is the main reason why most of the tenants and companies agree not to use it.

http://www.renovacija.lt/statybu-sprendimas/fasado-apdaila/

GABIJA KALTENYTE 3.2.

Alternative methods

Since external renovation considers only the old façade and its thermal bridges and properties, architects and engineers have started to look for new ways and methods to make these buildings more suitable for tenants, yet some of them believe that the best way to deal with them is to demolish it and build new ones.

3.2.1. Demolition and re-building

Demolition of panelak buildings have been a hot topic for over 25 years now, since the former Soviet Union broke down. A lot of people feel that anything that reminds of this part of history should be demolished and buried in the ground, and it has been done in Berlin, where 350 000 apartments were planned to be demolished in 2005-20075 and the concrete was recycled for re-usage in road and infrastructural construction, as well as recycled for use during new constructions, most commonly as an aggregate. The plan of demolition and recycling sounds great, so why isn’t this happening anywhere else? The answer is pretty easy- tenants. After Germany’s both parts were reunited, a lot of people have moved to the Western part because of better economy, and Eastern Germany’s population have decreased, leaving thousands of empty apartments in block housing estates. This let the municipalities to start demolishing the buildings easier since they did not have to move the tenants away and build new houses straight afterwards, something which should be done in other countries and cities in order to demolish the panelaks. Every of these houses are homes to thousands of people, generations have lived there since 60’s and most of the people do not even have where to move. If the governments would agree to start demolishing the buildings, they first should build new housing estates for the families to move in to, and this would be a huge investment which Eastern European countries cannot afford. Another problem is that during those 25 years a lot of these houses managed to fix the buildings partially, renovating roofs, adding new elevators and renovating the apartments, which was a huge investment for the tenants. Therefore most of the neighborhoods are partially broken, partially fixed. The last problem involving demolition is the owners’ rights. Some of the buildings have a building administration and board to take decisions for the whole housing estate, but most of them don’t and every apartment belongs to a different person, not a company or association. Therefore if these buildings would start to get demolished, the governments would most probably have to re-buy every single apartment from its owner and that would be, again, not affordable for the country, and of one person would not agree to sell the apartment- the building would have to stay.

The Guardian, ‘Cut down to size’, 2005

GABIJA KALTENYTE 3.2.2. Full renovation

Since demolition or external renovation is not always the best answer to the issues found in prefabricated concrete element buildings, many architects have been trying to create projects dedicated to full renovation of such buildings while keeping the existing corechanging the apartments, installing new ventilation systems, adding penthouses or even green roofs, renewing the building envelope. Master re-planning. When planning to change the master planning of a mass housing building, the surroundings should be adapted to the needs of nowadays families. When it comes to parking, it is very obvious that the parking lots are insufficient, and each apartment should get minimum two spots for cars in the parking area, considering the cars per capita statistics in Lithuania, Slovakia and Bulgaria: Country Bulgaria

Cars per capita, per 1000 people 393

Lithuania

560

Slovakia

364

Figure 2. Cars per capita in LT, SK and BG6

The chart shows that the situation is worst in Lithuania, where most of the parking lots in mass housing neighborhoods looks overcrowded, and a lot of people are forced to park on the grass, children playgrounds or somewhere far from their home.

Image 12. Parking in Lithuania, Kotryna Malikenaite, 2015

World Bank Data, 2010

GABIJA KALTENYTE Re-planning of the apartments. Since 49% of people who participated in the survey agreed that the apartments are too small and badly planned, it would be very sufficient to change the layout of the apartments, and if possible to build extensions for bigger apartments. Most of the flats are homes for families, which means there are multiple children living together with parents, yet the flats have a maximum number of three rooms per apartment so children usually grow up while sharing a room. While a lot of psychologists and sociologists has an opinion that it is very advantageous to share a room with a siblings while growing up and it helps to develop greater social skills, most of the children want and Image 13. Regular bathroom in Lithuania, need their personal space by the time of teenage Tomas Sviokla, 2015 years while developing their personality. 7

Re-planning the layouts of the apartments should definitely include changing the positioning and areas dedicated to kitchen and bathroom together with the entrance

Image 14. Common apartment layout in Eastern Europe, 9 floor building, not changed

Katherine Salant, 2013

GABIJA KALTENYTE hallway, since most of them are very small, as it is possible to see in this plan of a 3 room apartment in Vilnius, Lithuania (Image 14).

Image 15. Same apartment after a common renovation done

When the buildings were constructed, even being equipped with a toilet and a bathtub in the apartment was seen as very high-class and the size of the rooms for tenants did not matter much. But nowadays, when after all the crisis that Eastern Europe has been through, more and more families and people owning apartments seek not only a roof on top of their heads, but also started to look for more beautiful and comfortable ways to live, including having more fancy and more spacious bathrooms. Also as interior design has unwrapped dramatically in this part of Europe after the communism times, the design and cheap materials used back then do not satisfy tenants anymore. As shown in the picture above, where a typical bathroom in Eastern Europe is captured (no renovation in the apartment has been made, Picture 15). Therefore re-making the apartments in more modern places to live has become a common practice, where apartments as shown above can be changed to more spacy and comfortable flats: Other issues. If a full renovation is being done, it is possible to solve most of the problems in the buildings. In order to make the construction better and more sustainable, houses can be insulated from the outside or inside, and ventilation systems installed to avoid mold growth inside of the apartments. Ventilation systems would also help with thermal loss in kitchens and bathrooms, where there are pipes going straight to outside with no regulation 16

GABIJA KALTENYTE of it. Since thermal loss is a big issue in prefabricated concrete mass housing, good renovation can not only make the living more comfortable, it can reduce bills dramatically and help the country to move to more sustainable housing model. When adding the insulation, adding an extra layer between the apartmentâ&#x20AC;&#x2122;s floor and wall wise would increase the sound conditions in the apartments, helping to lower the surrounding noises. In order to create better conditions for handicap people, installing ramps or adding an extra opening at the ground floor could help, as well as equaling the floors inside the apartments for a better access and living conditions. 3.2.3. Re-usage of concrete panels.

During the last 25 years a lot of architects and engineers have come up with different solutions for re-using or recycling the concrete panels, such as using the concrete for roads, pavements or recycling it while mixing it with new concrete and building houses out of it. A new and very innovative solutions for this has been recently found by Herve Biele- an architect based in Berlin, Germany while researching the subject sponsored by Institute for Building Preservation and Modernization at Berlinâ&#x20AC;&#x2122;s Technical University 8 . As an architect interested in sustainability and recycling, he prepared a project and managed to get it built just outside of Berlin in Mehrow- recycled house. H. Biele, while working closely with Claus Asam, used prefabricated concrete panels which used to be a part of mass housing estate block to create new two storey single family houses, which according to the architect cost around 30% less than designing a new building the same size. In an interview taken by The Guardian in 2005, the architects stated that the biggest advantage of such housing solutions is panels which his company can take for free from the demolition sites, and all he has to do is to rip off the existing wallpapers and prepare the panels for the next life as a new single family house.

Image 16. Re-used panel building in construction and after walls have been rendered, conclus.de, 2005

http://architecturemag.typepad.com/my_weblog/2006/07/cut_and_paste.html

GABIJA KALTENYTE In order to make sure that the panels are safe to use, H. Biele is taking samples of each panel for certification, and new bolds and ties are used to keep them together once they are re-assembled to a new site. In his research, the architect states that the concrete used in the panels not only became weaker during the years, but in fact stronger after all this time it had to dry out well. The innovative architect has put a lot of insulation on the exteriors of the panels to create a warm and more sustainable housing solution, and by his calculations, the single family houses needs to be heated only 20% of the year. The only problem the architect has encountered is a high price for lifting the panels, transporting them to the site and assembling them into houses, because of big size and weight of the elements. But even while constructing his first house, which was a flat roof two storey building, of 215 square meters and it took his company only 7 days to construct the house. As for tenants, the only problem with living in such houses is hanging painting or lamps on walls- because of all the time concrete had to dry, now it takes quite a hard work in order to put a nail in the panel. The whole project would be very easy to complete if it was executed in bigger scale, such as dismembering whole neighborhoods and testing, transporting and assembling the panels at once- that would cut the costs of construction dramatically. This is an absolutely astonishing example of re-usage of prefabricated concrete panel buildings, which in a lot of countries has become headache to the government, tenants and the architects. Once highly desirable, nowadays the houses are considered to be a scar on cities skylines. It is also a very sustainable solution in comparison even to new panels made out of recycled concrete, considering the fuel and energy needed to recycle the concrete. All in all, the solution is still in his first stages as the very first families are finding their homes in such structures, but hopefully more and more architects and governments will find interest in such sustainable and thoughtful way of re-using the prefabricated concrete panels. Image 17. Time lapse, Jan Otakar Fischer, 2006

GABIJA KALTENYTE

4. Implementing sustainability The last 25 years in the construction field have been concentrating a lot on sustainability, from clients to project developers trying to find better and better ways to implement different solutions, from green facades and roofs to renewable energy sources. Sustainability is divided into three main areas9 (Figure 3). A lot of different certification programs have been developed, two biggest ones being used in Europe incudes: LEED- Leadership in Energy and Environmental Design, based and developed in the United States by U.S. Green Building Council, a non-profit organization founded in 1993. LEED has a certification program, where a building can receive a certain level of reached sustainability once the project satisfies certain criteria. There are different rating requirements created for different areas- building design and construction, interior design and construction, building operations and maintenance, neighborhood development and homes. The certification system goes from certified to silver, gold and platinum10. DGNB- The German Sustainable Building Council (English for DGNB- Deutsche Gesellschaft f端r Nachhaltiges Bauen e.v.) based and developed in Germany, is aimed to promote sustainability and economically efficient buildings. The organization has been found in 2007 by 16 initiators from different building sectors. DGNB works as a non-profit organization and aims to widen the societies and companies knowledge in sustainability in more holistic point of view11. If renovated properly, even old panel buildings could reach the standards for the LEEDS certification. While LEEDS considers a lot of very different aspects of the building which can be found in LEED v4 for Building Design and Construction, most of them are great guidelines on how to create a better home which would be not only economically sufficient, but also protecting environment and build the foundation for social ECONOMICAL DEVELOPMENT

SUSTAINABILITY

SOCIAL DEVELOPMENT

ENVIRONMENTAL PROTECTION

Figure 3. Sustainability areas

United Nations, 2005 http://www.usgbc.org/leed 11 http://www.dgnb-system.de/en/ 10

GABIJA KALTENYTE sustainability. LEEDS also has guidance on renovation of the building, including material disposal, maintenance and so on. While LEEDS is something to show to the clients and municipalities as a proof that all the work done is really sustainable and satisfies all requirements needed to be called one, DGNB sustainability system is more of a guidance for architects developing the projects.

CORE CATALOG

Sociocultural and functional quality

Environmental quality

Economic quality

Technical quality

Process quality

Site quality

Figure 4. DGNB Core Catalog topics used in comparison

DGNB has prepared a Core Catalog for Urban Districts, including the guidance for specific areas which should be considered while carrying out a project, nevertheless if it is a new building or a renovation project. DGNB consists of certain areas (Figure 4). These areas can be used as needed, including or excluding different points for a specific project. If all renovation projects included at least half of points these two sustainability standards are offering, the building industry would be changed drastically, as well as the way we live- to our advantage. Sustainability in demolition. If decided to demolished, panel buildings can be recycled and used as an aggregate in road, bridge and new building construction. This is a very advantageous solution, considering that most of the materials are re-used. The only issue when it comes to sustainability is the energy needed to demolish the buildings and recycle the elements. External renovation. Implementation of sustainability in external renovation project completely depends on the client and the architect. Using this method the buildings can be left unsustainable if wrong and toxic materials are used, no attention is given to details and adapting green roofs, sealing the building envelope. Since the sustainability is not only energy demands, external renovation also usually excludes the social part of it- while installing the insulation no extra spaces and areas are created for social development of the society.

GABIJA KALTENYTE Full renovation. Just as previous, the extent of sustainability completely depends on the project. If taken at the best and most innovative, the panel building can be converted into sustainability oasis- well insulated building, green roof with social area, common areas in the building for activities, recreational parks and areas outside of the building. It is possible to include all points from LEED or DGNB criteria and get certified fully, if the project is carried out correctly. Re-usage of panels. While demolition and recycling is only half-way sustainable, re-usage of panels is one of the best sustainable methods of renovation and re-usage of panel buildings. While the transportation costs are still expensive, re-usage of elements saves a lot of work, energy and fuel needed to produce new concrete elements.

5. Comparison of methods There are very many ways renovation methods could be compared. In order to get the best results from the comparison towards sustainability, DGNB criteria will be used because of its coverage of all topics and areas. 5.1.1. Environmental quality

Full renovation and re-usage of panels were the only methods which could implement all 6 different tasks in this area, external renovation could only succeed in 4 tasks and only partially, and the buildings as they are today cannot satisfy any of the requirements. As expected, the two last methods are the best to use if the project wants to be as environmentally sustainable as possible- it is the only way to change most of the materials used to more environmentally friendly ones, adapt life cycle assessment and other methods used for improving the environmental quality of the building. All three renovation methods are capable of reducing the used energy, but only last two can reduce the water usage and increase the land use. Environmental Quality

Nowadays Building

External Full Re-usage renovation renovation of panels

Life cycle impact assessment

Partial

Yes

Local environmental impact

Partial

Yes

Responsible procurement

Partial

Yes

Primary energy demand

Yes

Drinking , waste water

Yes

Land use

Yes

Total out of 6

Figure 5. DGNB guidance used in criteria for Environmental Quality to compare different methods of renovation

GABIJA KALTENYTE

5.1.2. Economic quality

Economy is one of the three main areas in sustainability, therefore it is very important to consider when carrying out any project. When evaluating the methods of renovation economically wise, nowadays building shows no advantages over any method. The next method, external renovation is only partially improving the commercial viability and life cycle costs can also be done only partially. Both full renovation and re-usage of the panels can fully satisfy the economic quality criteria. Economic Quality

Nowadays Building

Building-related lifecycle costs Flexibility, adaptability

Commercial viability

Total out of 3

External Full Re-usage renovation renovation of panels Partial No Partial 2

Yes

Figure 6. Economic quality in DGNB criteria

5.1.3. Sociocultural and functional quality Sociocultural and functional criteria has 16 different points- from thermal and indoor air quality to public art and handicap accessibility. Most of these point are extremely important to satisfy the tenants of the building, and without them the building is unsafe, uncomfortable and unpleasant to live in. Full renovation can achieve all 16 tasks given, reusage of the panels- 15 (without the public art), and external renovation can only succeed in maximum 6 of the tasks. The buildings as they are now, can only comply with 3 criteria points already, but in order to reach the maximum sociocultural and functional quality of the building full renovation is the best method to use. While renewing the building envelope and ensuring the quality of interior conditions, full renovation can also cover master re-planning which could improve the quality of parking, outside spaces and cycling pathways, as well as ensuring that handicap people can also comfortably live in the estate (Figure 7).

GABIJA KALTENYTE

Sociocultural and Functional Quality Thermal comfort

Nowadays Building

External Full Re-usage renovation renovation of panels

Yes

Indoor air quality

Yes

Acoustic comfort

Yes

Visual comfort

Yes

User Influence on building operation Quality of outdoor spaces

Yes

Safety and security

Yes

Handicapped accessibility

Yes

Efficient use of floor area

Yes

Suitability for conversion

Yes

Cycling convenience

Yes

Design and urban planning quality competition Integration of public art

Yes

Site features

Yes

Public access

Total out of 16

Figure 7. Sociocultural and functional DGNB criteria.

GABIJA KALTENYTE

5.1.4. Technical quality Technical quality of the building is very important for existing and new tenants of the building, especially fire prevention, building envelope quality, sound insulation. Only full renovation and re-usage of the panels can satisfy the tenantâ&#x20AC;&#x2122;s needs, even though external renovation can fix the building envelope, it does not include fire prevention, sound insulation and ease of cleaning and maintenance. Panel buildings as they are today are only good for dismantling and recycling in this criteria. Technical Quality

Nowadays Building

External Full Re-usage renovation renovation of panels

Fire prevention

Yes

Indoor acoustics and sound insulation Building envelope quality

Yes

Adaptability of technical building systems Ease of cleaning and maint.

Yes

Resistance to hail, storms, flooding Ease of dismantling and recycling

Yes

Partially

Yes

Total out of 7

Figure 8. Technical quality criteria by DGNB.

5.1.5. Process quality Process quality includes building management from the project start to maintenance and commissioning. No matter how sustainable and efficient the renovation plan could be, without a comprehensive project brief, good tender phase and documentation all efforts can be wasted. Not surprisingly, the panel building got 0 points from the process quality, no work has been done in this area starting from project brief to quality assurance and commissioning. All other renovation methods can satisfy all the criteria, if the project is handled correctly and responsively.

GABIJA KALTENYTE

Process quality

Nowadays Building

External Full Re-usage renovation renovation of panels

Comprehensive project definition Integrated design

Yes

Design concept

Partial

Yes

Sustainability aspects in tender

Yes

Documentation for facility management Environmental impact of constr. site and process Construction quality assurance, quality control measures Systematic commissioning

Partial

Yes

Total out of 8 Figure 9. Process quality criteria by DGNB.

5.1.6. Site quality As important it is to have a comfortable and sustainable building, it is also extremely crucial to invest the money and time during the project into the surroundings. While external renovation can only fix the building itself, full renovation and re-usage of the panels can change everything- from parking lots to public transport routes. Re-usage of the panel building cannot change one thing though- access to the amenities. However, most of the mass housing neighborhoods have quite a good public transport planning and infrastructure- therefore the buildings have got 1 point in the table. Social sustainability is crucial when it comes to the building environment, therefore more renovation projects should concentrate on developing recreational areas to improve the atmosphere and safety.

GABIJA KALTENYTE Site quality

Nowadays Building

Local environment

Public image and social conditions Transport access

Access to amenities Total out of 4

External Full Re-usage renovation renovation of panels No

Yes

Partially

Yes

Figure 10. Site quality criteria by DGNB.

5.1.7. Conclusion After evaluating each renovation method by DGNB certification criteria, the final results can be seen in the chart (Figure 11):

Final results of DGNB comparison Sample building

External renovation

Full renovation

Re-usage of panels

0 Site

2 Process

4 Technical

Social and functional

12 Econom

Environment

Figure 11. Final comparison of DGNB criteria

It is rather easy to analyze the results of the comparison- full renovation and re-usage of the concrete panels can be the most sufficient in sustainable re-development and renovation, with total scores of 44 and 42. External renovation can satisfy only half of the conditions for sustainable certification of DGNB with a score of 24, and the buildings as they are now, panelaks could only satisfy 5 criteria.

GABIJA KALTENYTE

6. Conclusion Rapid evolution in technology in the past 25 years has let us to improve our houses significantly, making them more comfortable, healthy and sustainable. Yet, most of the houses in the Eastern Europe are built during the Soviet Union or communist times, when quantity and low price was more important than quantity and healthy and humane living conditions. The most common method used to improve the lives of these families is external renovation, which was already proven to be not completely efficient due to concentration and mold growth, or unimproved living conditions except heating bills. There are a lot of different possibilities already on the market, and therefore I have raised myself a questionwhat would be the most efficient way to renovate or re-use the panel buildings? In order to answer the main question, I first had to find the most common ways of renovation and alternatives for it. After researching on projects executed, I found out that the most common ways to renovate such buildings are (as follows): -

External renovation Demolition Re-usage of panels Full renovation

However, the most used method is not the most sustainable, as I have found out. In my last chapter I have compared all methods to DGNB sustainability certificate criteria, and external renovation was in the 3rd place out of 4. Since DGNB criteria considers a lot of different aspects such as site conditions, technical solutions, social, economic and environmental sustainability, external renovation could not offer much more rather than economic and environmental improvement. In contrast, full renovation seems to be the most sustainable and efficient way to renovate such buildings- it has absolutely no limits on the improvement and solutions of design. Re-usage of panels is the second best method, also letting the families to have separate houses for themselves, not 9 storey concrete box. As we found out there are so many ways to renovate these buildings and free the tenants from dirty and unmaintained environment, and architects and participants in the survey agreed that the buildings has no value whatsoever, so why are there thousands and thousands of panel buildings still standing, serving as homes to millions of people, you might ask? Sadly, there are a lot of barriers in the way, Eastern European countries underwent several serious economic crisis, and there are still bigger issues to solve, as well as most of the people have already accepted these houses to be their home, no matter the conditions, realizing that nothing is going to change in the next 20 or even 50 years.

GABIJA KALTENYTE In conclusion, renovation is becoming bigger and bigger building sector as we move along our way to improve the houses we already have, not only build new ones. More and more alternatives are being found and used in renovation, and more are yet to come, changing and improving the lives of tenants in communistic mass housing. As we are moving towards as sustainable society and cities as possible, we realize that without finding an effective way to solve this issue we are getting stuck, leaving these concrete boxes to use twice or even three times more energy than a same size house would. After all, there can be no evolution without a challenge, and this is a good reason for everyone in the building sector to keep developing the renovation and find a way to solve this issue, concerning millions of people from Sofia, Bulgaria in the south-east to Tallinn, Estonia in the North.

GABIJA KALTENYTE

Bibliography 1. Dluhosch, Eric. The minimum dwelling. Prague : Vaclav Petr, 1932. 2. Nations, United. Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat, World Population Prospects: The 2010 Revision and World Urbanization Prospects: The 2011 Revision. Country Profile: Czech Republic. New York City, US : United Nations, 2012. 3. Association, Building Modernisation. http://renovacija.lt. Renovacija. [Online] 20142015. http://www.renovacija.lt/statybu-sprendimas/fasado-apdaila/. 4. Cut down to size. Anonymous. 2005, The Guardian, p. 5. 5. Nations, United. World Summit Outcome. New York City : United Nations, 2005. 6. Data, World Bank. Motor Vehicles (per 1,000 people). Washington, D.C. : World Bank Data, 2010. 7. Salant, Katherine. Emotional Intelligence: Katherine Salant. Katherine Salant. [Online] 2013. http://www.katherinesalant.com/columns/column011.html. 8. Cut and Paste. Fischer, Jan Otakar. 2006, Architecture, p. 3. 9. LEED. Overwiev of LEED. Leadership in Energy and Environmental Design. [Online] 2012/2015. http://www.usgbc.org/leed. 10. DGNB. The DGNB Certification System. DGNB System. http://www.dgnb-system.de/en/system/certification_system/.

[Online]

2015.

11. â&#x20AC;&#x201D;. Core Catalog for Buildings. DGNB System. [Online] 2015. http://www.dgnbsystem.de/fileadmin/de/dgnb_system/_system/core_catalog_700.png.

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Used literature Hard copy books: Kimberley Elman Zarecor. Manufacturing a social modernity. Housing in Czechoslovakia 1945-1960. 2011 Henrieta Morancikova. Bratislava: Atlas of Mass Housing. 2012

Other literature: Kimberley Elman Zarecor. The rainbow edges: the legacy of communist mass housing and the colorful future of Czech cities. 2008. [Architecture conference papers, paper 26, PDF] Frits Meijer, Laure Itard, Minna Sunikka-Blank. Comparing European residential building stocks: performance, renovation and policy opportunities. 2010 [Online] Sonia Hirt and Kiril Stanilov. Revisiting urban planning in the transitional countries. 2009. [PDF] Sonia Hirt. Post- socialist urban forms: notes from Sofia. 2006. [Published in Urban Geography, 2006, p. 464-488, PDF] Paul Waide. High-rise refurbishment. The energy-efficient upgrade of multi-story residences in the European Union. 2006. [PDF] Roeleveld-Sikkes Architects. How we really live in panel blocks. Case study on the conditions and potentials. 2006 [PDF] Yelena Zubova. St. Pete leaves Khrushchev houses to investors. 2004. [Article in The Moscow Times, PDF]