Renewal of a big high density housing block in Berlin Kreuzberg.

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1 Renewal of a big high density housing block in Berlin Kreuzberg. Stefano Giussani University of Genova, Faculty of Architecture, Italy ABSTRACT: This project is the renewal of a large high density-housing block built in West Berlin (Kreuzberg) in the 60, called Grey Louse. The plan had to deal in one hand with complex social issues and in the other with technical and economic constraints that this kind of profit mass housing gives. Kreuzberg is a multiethnic district and the most users living in this building are subsidy aided. The first step was to avoid the usual way of demolition/reconstruction (and so the gentryfication process), following a strategy to improve the high site potential the and keeping the actual users. The strategy applied in this project was: the fragmentation of the block in 4 parts, the involvment of users in the design and the low economic profile of tecnology in the proposed solutions. 1 THE HOUSING HERITAGE FROM THE 60 IN EUROPE. The condition of the greater part of the housing heritage built between the 60 and 80, seems to be in the urgent needs of refurbishment an renewal, concerning social, energetic, technological and infrastructural issues. The past vision of large social clusters with few collective scenarios crumbled with the end of the emergency of housing need after the war, the common rise of the life quality, and, above all, with the emerging of unexpected social situations, like immigration, that nowadays involves the whole Europe. These conditions have produced since the 80 a rise of the general renovation demand of the housing building stock. 2 THE GRAY LOUSE OF WASSERTORSTRASSE IN BERLIN. The project is a renewal of a big high density-housing block built in West Berlin (Kreuzberg) in the 60, ironically called Grey Louse by the district s inhabitants. The planned intervention had to deal in one hand with the complex social issues and in the other with structural and economic constraints that this kind of mass housing s architecture gives. Kreuzberg is a multiethnic district and in the building lives users that are in the greater part subsidy aided. The first step was to avoid the usual demolition/reconstruction attitude within the gentryfication process, elaborating strategies able to improve the high potential of the site and to keep the actual users in order to preserve the human landscape. This building was constructed at the end of the 60, by the GEWOBAG Company, as the most in the district, with a prefabricated concrete panels building system (15 cm of thickness), very dense (from 2.4 to 3.5 m of span). The building is 15 floors high, hosts 280 flats whose surface is mainly of 56 and 74 sqm and a few of 32 sqm, arranged in only one single standard floor.

2 The general degraded state of this building is due to the low quality of construction materials that gives also negatives performance in energy consumption and life quality, and to a social complexity condition, like overpopulation of inadequate size flats. figure 1. Overview of the project site and the building in Wassertorstrasse in Berlin Kreuzberg. 3 STRATEGY OF FRAGMENTATION. The whole solid building was divided into 4 unit houses (as load bering structure suggest) allowing in this way to consider progressive renewal intervention from unit to unit. A structural/functional building scheme has focused different layers of intervention corresponding to different floor position (ground, standard floor, upper floors) Fragmentation strategy correspond to the needs of a long term building cost management in order to guarantee the renewal reliability in this particular kind of social and economic context. fragmentation strategy means also to observe and to test the results of the intervention in any unit, having the opportunity to change and optimize solutions, always involving the users in the process. The fragmentation into 4 houses aims to better coagulate neighbourhood relationships, to ensure a good security level and to break the typical impersonality feeling of this kind of high-density building of the 60. The improving the sound insulation will provide a better privacy too. As told before, the actual range of flats is of 3 types ( sqm) arranged in one only standard floor. The fragmentation strategy allows a partial redistribution of the apartments in order to offer an adequate range of types to different users with different needs, setting a typological matrix of 26 types arranged on 4 floors, considering the partecipation of the users in the design process.

3 Figure 2. Fragmentation in 4 houses with new distribution and scheme of typological matrix on 4 floors. Figure 3. Virtual plan concerning the use of room for the composition of the external enclosure system. A façade scheme was compiled setting a virtual use plan of every room. On this base was elaborated a courtain wall, 1 meter deep, on a semi-indipendent external structure. This skin is composed by 4 basic enclosure systems and their variation, depending by environmental factors.

4 These systems were conceived to be an external interface that use only save/gain energy technology, combining many factors that comes from the environment and from the interior of the building. The opportunity to set the façade in relation with climatic and seasonal condition make this building (basically every single room) react continuosly where is worth to do it, and changing as a green façade do. Terrace, wide windows and the way to stare at them are conceived to enjoy the potential of the landscape. Figure 4. transformation of distribution and detail on the substitution of the facade.example of one type of modular closing system with bioclimatic solutions.

5 Figure 5. Other modular closing system of the facade and their derivation for the higher floors.

6 The external enclosure systems on higher floors are adaptions of some modular panel of the middle part to the relevant air turbolences. This need match with the intention to give a roof to the building and then to obtain a more reassuring visual impact with the context. In this way the enlargement of the street tunnel aims to turn off the barrier building in a district portal concerning the urban dynamics of the site. On the roof thermosolar panels are planned for water warming. On groundfloor passages are restored and unused rooms are redistribute to improve the Gallery (in the former commun laundry) as social cathalist. A light building site was planned in order to keep tenants in their flats and to make affordable the intervention discomforts, providing containers as forniture storage or room substitution. The building site is large as two flats and it can shift gradually by moving hits elements orizontally. Figure 6. Example of the light building site for incremental strategy and overview of the project.

7 4 CONCLUSIONS. First consideration must be about the context of the mangement of the existing building stock of the 60 speculation. It still remain an emergency situation related to this problem, expecially considering the renovated trend of total demolition promoted by politicians, clearly an unadequate answer to the dynamics that turned the existing social hardship into social emergency. In the former East Germany was recently planned the demolition of vacant lodgings, in France is promoted the complete demolition of the grands ensembles, that means to pull down about 6 millions of lodgings in wich lives about 10 millions peoples. This initiative looks quite ambiguous as far as seems loaded of postmodernist preconceptions with a paradoxical reproposition of a new tabula rasa. Is easy to think that this trend could be driven by the politic s interests about gaining general consensus and by the prospective of great economic results concerning the process of gentryfication of reconstructed areas. Here we wants to say how important is to keep the footprint of both urban and human landscape with their memory and meanings. In this we see the capability of an urban sustainability for the inhabitants out of triviality of gentryfication conceived as treatment. In such a context of heavy heritage, full of human matter, is hard to operate requalification following sustainability principles. In one hand having to deal with a complex social issue and in the other with structural and economic constraints. The goal of this kind of project is the implementation of the quality of life within the quality of spaces, joining the need to apply an adequate technology, in order to afford feasibility in the economic context. Following these principles all the design and all the intervention strategies were conceived to maximize performance and minimize costs. All the variations for the modular enclosure panels were designed to obtain difference with minimal change, always related to industrial production. In the same way the internal modifications where minimized within the costs. On the façade only energy saving/gain solutions were used (insulation, Trombe-wall, greenhouses, wide glasses), on the roof energetic gain with thermosolar panels integrates existing facilities. The guide lines of the design project where to avoid to design special components, to provide only manual setting systems, to employ only standard technology (easy to found in future and easy to replace), and to apply easy maintenance design. The LCA would be included in further material design for the solutions process. This use of standard conponents and save/gain-energy technology aims to partially absorb the cost of the new rent after the refurbishment, following the idea of keeping the actual users (that in the greater part are subsidy aided) after the refurbishment. Out of general considerations about typical problems of 60 mass housing, the project intends to turn off the concepts of Block-barrier-Dam-Plattenbau-Unity-Equality (that comes from social and urban analysis) into Complexity-Multiplicity-Variety-Difference-Identity. In this way the project act on different scales with an increasing strategy and the fundamental collaboration of the users (is important to remember the Kreuzberg experience on partecipated requalification in the 80). In conclusion the goal of this kind of requalification would be the offer to the district s people a scenario of opportunity of change, with the perspective of a better conditions where to live.