• Housing associations can de-risk projects and assist smaller groups who want to design and commission their own homes
  • Building groups can form part of a wider social housing project alongside other tenures – such as assisted living and social housing – and can address the specific social needs of some groups (larger families, the elderly, etc.)
  • Small building groups can pool their resources with other groups (or partner with a housing provider) if they are struggling to afford a site
  • Building groups can access alternative finance streams – this can turn projects that are not stacking up into ones that are viable
  • People who ‘drop out’ are commonplace on group projects, as the time between founding a group and moving in is often quite long
  • Umbrella groups – like Arche Nora – can ‘feed’ their members into individual development projects, effectively ensuring that a large pool of candidates exists as a waiting list


This project was led by the Altoba cooperative – or Altonaer Spar-und-Bauverein eG (‘Altona savings-and-building society’) – founded in 1892 and based in the Altona district of Hamburg. The cooperative builds two or three new projects each year and currently manages around 6,500 homes. It is controlled by its tenants, who are cooperative members, and currently employs around 100 people. The Kleine Bergstra?e site was released by the city of Hamburg as part of a wider initiative to support the city’s social housing providers. The city has an established programme of support for building groups, which it sees as vibrant contributors to the city’s housing market. When land is released to developers they are often required to work with groups on specific sites. Further information on how Hamburg encourages groups this is available in Briefing Note Help and support for groups. Altoba responded as the enabling developer for the site and managed the construction, finance and the integration of various partners, including two building groups – Baugemeinschaft Arche Nora (the ’Nora’s Ark’ Building Cooperative), which wanted to create a mutually supportive community for single, older women); and Baugemeinschaft Neuhaus (the ‘New House’ Building Cooperative), organised around the concept or intergenerational family living. The project also includes subsidised rental apartments for Altoba’s usual beneficiaries, as well as a residential care community for people with dementia and other cognitive diseases. For Altoba, the project was an experiment with the idea of ‘different homes under one roof’ – a concept that fits with its social objectives, but which it had not tried before on such a scale. Altoba owns the land and buildings – and the building groups and special care unit are its tenants. From a housing and public policy perspective, it is the mix of accommodation that makes the project special, making inter-generational living almost inevitable.  


Completed in 2012, this project contains 55 rented apartments delivered by an enabling housing provider and includes two building groups as part of a wider concept of ‘different kinds of living under one roof’. One group is for older women who want to live in a mutually supportive environment and the other group is organised around the concept of intergenerational living. The housing provider also incorporated subsidised rental apartments and a residential care community, as well as shared outside space and common rooms.   cs-community-icon Initiator: Housing Provider cs-medium-scale-icon Scale: Medium cs-suburban-rural-icon Site: Urban low-intermediate-cost Affordability: Low Cost cs-individual-collective-icon Opportunity: Collective cs-detached-terraced-apartments-icon Built Form: Apartments cs-uk-icon Country: Germany  

Key Statistics

Completed  2012 No. Units   55 Total Floor Area  4,400 sq m Construction Cost €13.7million


The project was constructed on a former car park in the Altona district of Hamburg, close to the pedestrianised shopping street of Gro?e Bergstra?e (which features the world’s first town-centre IKEA) and to the Altona railway station. It is also close to the green banks of the River Elbe, and as such, has high recreational amenity value. The project represents a moderate densification of the area, but without increase in the original built footprint. A children’s playground is located to the north and the new homes are grouped around a landscaped courtyard garden. The end result is a socially ambitious housing project in a central location, within a city of high land values.


For the purposes of this Toolkit we have made the following definitions:
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  • ‘self and custom built homes’ as properties commissioned by people from a builder, contractor or package company (this is known as ‘custom build’ housing). When people physically build themselves, sometimes with help from sub-contractors, this is known as ‘self build’ housing. We call all these people ‘private homebuilders’.
  • ‘serviced building plots’ are shovel-ready parcels of land with planning permission, laid out and ready for construction with access and utilities/services provided to the plot boundary. Some private homebuilders just purchase a plot; others opt for a ‘shell’ home (that they then finish off), or they select from an extensive menu of options offered by developers/builders.
  • ‘group projects’ mean homes built by private homebuilders who work as a collective.

Number of units and types of people 

The project provides 55 units and 35 underground car-parking spaces to replace those formerly on the site. The homes are organised into five ‘houses’ that share a large communal garden.  Altoba directly manages three of the ‘houses’ including the assisted living accommodation, while each building group has its own ‘house’. Plan showing the relative arrangement of five ‘houses’ (Haus 1, 2 and 3 managed by Altoba, Arche Nora and Neuhaus) in one block (or ‘under one roof’). The project has a shared garden and vehicular access to the south, and borders a small park/playground to the north Each building group (called a ‘Baugemeinschaft’) came together around a particular idea about how they wanted to live. For example the Baugemeinschaft Arche Nora group, commissioned a set of homes where elderly women could support each other as they aged, but where each had their own flat. The neighbouring group – called Baugemeinschaft Neuhaus – formed around a more general concept of inter-generational living. Both groups were interested in the opportunity to customise their homes to suit these living concepts.

Arche Nora

Arche Nora was founded by three women in 1995 as a ‘club’ to support and pursue alternative food and housing initiatives for women in old age. Since then its interest has broadened to include inter-generational living. Its aims are to enable older women to live largely independent lives in a familiar social environment through mutual support. The goal is the removal of the negative effects of single living – such as isolation and exclusion. The organisation has developed a strong relationship with a specific architect, who understands the needs of its members. Kleine Bergstra?e is its third project in Hamburg (with a fourth at planning stage) and the residents are selected for each project from a wider Arche Nora waiting list. In the Kleine Bergstra?e project, the majority of participants were aged between 56 and 73. As with all Arche Nora members, the members did not want be a burden to their children, or be moved into a retirement home – and they wanted to ‘tackle the adventure of ageing with their peers’. Residents are not required to put in any equity, but must take shares in Altoba as members of the cooperative. They then rent their apartments at rates agreed with the City and in-line with their incomes. The Arche Nora umbrella group has a contract with Altoba which allows it to nominate new residents to fill any vacancies at Kleine Bergstra?e. The right is time-limited, after which – to guard against significant voids – Altoba can nominate residents from its own lists. For further information see (in German).   Baugemeinschaft Arche Nora commissioned 13 one-bedroom, ‘age-appropriate’ flats of 48 , 54  or 57 sq m, as well as a common room and communal roof terrace. As most group members were widowed or had never married, single-occupancy was a condition of residence – and one group member even had to leave the group before completion, as she’d found a new partner. Demand for this kind of living was strong so the group was able to draw from the larger Arche Nora pool to replace her. The homes were designed in collaboration with the nominated residents, who could choose their interior finishes and layout within a pre-defined set of variables, controlled by Altoba and the architect. Baugemeinschaft Neuhaus provides 17 apartments of varying sizes from one to four bedrooms, designed around the group’s preference for inter-generational, family-oriented living. The group’s residents are a mix of singles, couples (with or without children), and single-parent families. A large community room is also provided, along with a shared roof terrace. The group also chose to link some of the external balconies on the apartments to provide larger shared external spaces. The assisted-living apartment for the Dementen-Wohngruppe (‘dementia residential group’) is about 380 sq m in total and has ten single, residential care rooms with ensuite showers, round-the-clock care and lots of shared space, including a spacious kitchen. A large private garden area is designed to match the needs of people with dementia. The architects aimed for a “normal” and familiar living environment, disguising the fact that the whole apartment is designed for disabled guests. Altoba also rents 24 dwellings directly to its usual beneficiaries, which are between 57 and 119 sq m in size and designed to be ‘family-friendly’. Each has between one and four bedrooms. All the homes are equipped with a kitchen, a full bath and a balcony or terrace.

Shared spaces

AThe Arche Nora house also contains space for meetings and joint activities, including a 26 sq m common room equipped with a kitchenette, a separate toilet and a terrace with direct access to the shared garden. The common room can also be used as a guest room for overnight stays. The group also has access to its own shared roof terrace with a unique view of the rapidly developing district of Altona. The Baugemeinschaft Neuhaus house has a slightly larger common room – which it shares with Arche Nora residents on the odd occasion – for example, when Arche Nora’s music group wanted to put on a small concert. It is possible to read the different approaches each group has taken when looking at the façades – the Neuhaus group has linked the balconies of the individual apartments, so their children (and adults!) can roam freely across these common areas. By contrast, Arche Nora has individual balconies to provide private outdoor space for sitting. A view from an Arche Nora apartment towards the Neuhaus ‘house’. Most balconies at Neuhaus are linked allowing children (and adults) to freely interact, while Arche Nora resident’s each have their own private realm to arrange as they wish The shared courtyard garden includes play space and direct access to the common rooms Common rooms are provided at a ratio of 2 sq m per apartment and are light, airy and have direct access to the shared courtyard garden. Arche Nora’s common room can also be used for temporary overnight accommodation The roof terrace is simple but is well used by residents for barbecues and for private gatherings when people do not want to use the more public shared garden Easy access to the outside is possible from every apartment

Land and Planning

The site is located in the heart of Altona Altstadt with good infrastructure and a high recreational value due to the surrounding green areas and the nearby river Elbe. The bus stops almost on the doorstep, and there is easy access by foot to nearby shops, which particularly suits the elderly members of Baugemeinshaft Arche Nora. The site was a former car park, and needed to be officially re-designated for housing, after which the sales contract was agreed. The city of Hamburg signed a cooperation agreement in 2008 with two large, regional housing associations, agreeing to make land available for their members’ at a 20 per cent discount on the market value and with Anhandgabe (“option periods”). The land release also came with the condition that those taking up some plots had to work with building groups, which the city wanted to encourage in recognition of the contribution they continue to make to the city’s urban development. Maximum rents were set for the apartments built on the land. Altoba responded to this opportunity and, although it was required to cooperate with building groups, it was free to choose which groups to work with. The organisation arranged appointments with interested groups, so it could screen out the ones it didn’t feel were stable enough. Arche Nora was selected because its umbrella organisation had completed two previous projects, including one with Altoba and because its membership pool meant it could replace any drop-outs easily. The group is currently working on a third project with Altoba. The site would have been too expensive for either building group to purchase on its own and so the involvement of the Altoba cooperative has opened up the opportunity for them.

The German planning system in use at Kleine Bergstraße

The site was released through the II. Wohnungsbau offenisve (‘2nd residential building offensive’), a municipal initiative that seeks to accommodate Hamburg’s growth. The accompanying Zukunftsplan Altona (‘Future Altona’) initiative set out a mission statement for the area, describing possible uses for buildings. This identified areas that could be turned over to housing as part of a neighbourhood densification plan. The site is within a redevelopment zone defined by the Zukunftsplan, called Altona-Altstadt S5- ‘Große Bergstraße/ Nobistor’. This sought to consolidate the historic Altona district for residential purposes, so casinos, betting shops, nightclubs and ‘sex shops’ were excluded from the area’s redevelopment. Altoba developed the project within the rules set by the Bebauungsplan ‘zoning plan’) for the block (Altona-Altstadt Nummer 58). This was developed by the City to reflect the neighbourhood principles of the Zukunftsplan and it specifically defines the planning rules for any new construction on the block. The Bebauungsplan also sets out the envelope within which the project has to be designed. Provided Altoba kept within this envelope, it knew it did not have to go back for planning permission. The planning law for this city block is defined by a Bebauungsplan (‘building plan’) – which sets out building lines, and broad uses for different parts of the site. The intention in Alte Altona was to restore the city structure of perimeter blocks (blue outline)

Design and Construction

The whole scheme has been designed by Huke Schubert Berge Architekten, a Hamburg firm with extensive experience of working with building groups. The 55 units are collected into five ‘houses’ that share a common courtyard, as prescribed by the Bebauungsplan. The blocks are four-storeys high, with a penthouse level and roof terraces, giving a total floor space of approximately 4,400 sq on a plot of approximately 3,200 sq m. An existing park to the north of the site was modernised as part of the project using City funds and to designs produced by Altoba. The former car park/garage that stood on the site was removed and a new underground garage has been built beneath the buildings. Design drawing showing the five ‘houses’ combined into one block, sheltering a shared courtyard garden – courtesy of Huke-Schubert-Berge Architekten All apartments benefit from good daylighting, with open floor plans and their own balcony or terrace. There is also a shared lift to the underground parking. Each flat has its own fully-equipped kitchen, and a bathroom with a bathtub. The architect accommodated the different preferences of the four tenant organisations, within limits set by Altoba and based upon the cost and viability of the development. The apartments are also built to the KfW-Effizienzhaus-70 (‘Efficient House’) standard, including heat recovery, which means they use 70 per cent of the energy typically required by a new building at the time. The new buildings reinstate the ‘perimeter block’ typology for the area Access is maintained at the rear of the block and the shared garden is separated from it Altoba acted as client for the project and took on responsibility for representing the views of residents in discussion with project consultants. Residents were able to influence the distribution of the apartments and bath and kitchen equipment within their apartments, during the initial design process. At later stages, they were able to choose paints, tiles and flooring, specify an open-plan or closed kitchen, choose where internal walls were and which way doors swung. Other specific requests were accommodated at the design stage. For example, the Neuhaus group requested that partitions between their balconies be omitted on one level (although one partition has since been added back). The group also asked that a second staircase be removed from their part of the building; they argued that a single common, portico-style entrance, connecting all residents on one level would stimulate conversation between them. The Arche Nora group was able to stipulate a focus on barrier-free design for its apartments. Two typical flat plans in the Arche Nora building group; 53 sq m (left) and 56 sq m (right) – courtesy of Huke-Schubert-Berge Architekten Plan of the ten-room assisted-living unit at the western end of the bock – courtesy of Huke-Schubert-Berge Architekten


Because the site became available through a special release of land for building groups, rent levels have been set as a condition of finance from the city’s IFB bank and relate to income ranges. The initial monthly rents for general apartments was set at €5.70 per sq m per month and at between €6.30 and €6.90 per sq m per month for the building group apartments, as these residents tended to be better off than Altoba’s usual clients. The average rent across the scheme is currently €6.36 per sq m per month (as of May 2015). The smallest flat (42 sq m) therefore costs around €240 per month, whilst the largest apartment (108m sq m) costs around €615 per month. Altoba also receives a subsidy from the city council of €1 per sq m per month for its standard apartments, and €1.50 for the building group apartments.


The total construction cost was about €13.7m. Altoba secured approximately €6.9m in development finance provided by the city’s housing credit institution (“Hamburgische Wohnungsbaukreditanstalt”), which consolidates several finance streams administered by IFB Hamburg – a bank owned and controlled by the City of Hamburg. The special funds include: –
  • Mietwohnungsbau 2010 (“rental housing 2010”) programme for the units retained by Altoba
  • Baugemeinschaften 2010 (“building cooperatives 2010”) for units taken by the two building cooperatives, and
  • Besondere Wohnformen 2010 (“special housing 2010”) for the dementia-oriented units
Additional funds of €2.5m came from a special funding programme to support energy-efficient construction (the “Energieeffizient Bauen” programme) administered by Germany’s national development bank (the “Kreditanstalt für Wiederaufbau” – or KfW). The remaining €4.3m came from Altoba’s own equity and a further loan from Altoba’s internal loans department (“Sparabteilung”), which draws on savings deposited with the cooperative.

Decision-making process and collaborative working

CS16---Img10---Collaboration Diagram of the collaborative working process employed by Altoba and its partners on this kind of project. Baugenossenschaft BVE + altoba (top; blue) are two large cooperatives who commonly develop projects together. On the Kleine Bergstra?e project, only Altoba was involved. The cooperatives contract directly with Huke-Schubert-Berge Architekten (bottom; purple) who provides ‘planning participation’ services to the building groups, alongside traditional architectural services. BG ‘Flickwerk’ (left; green) refers to the building groups. These are considered as a single group for the purposes of a structured decision-making process. They have a contract with Altoba that details the participation of the group members in the development process (a requirement of the land release). This comes with a right to occupy the homes that are produced. The groups also have a direct relationship with the architects for the purposes of design. The building groups are contractually linked to a ‘Baubetreuer’ (construction supervisor) whose job it is to help them make decisions by the deadlines set by the development programme. The Baubetreuer also helps the groups form a legal entity and they act as the groups’ nominated representative in the development team for any decisions that must be made as a group. For further information on this role, refer to Briefing Note Help and support for groups. The blue box on the right refers to other people involved in the development process, including planners, engineers (structure, environment, etc.), contractors, lenders, building inspectors, neighbours (within the block defined by the Bebauungsplan) and the city’s housing department, through whom the land-release was made. What kinds of decisions does each partner make? The lead development team makes high-level, strategic decisions concerning the overall financial health of the development. This team also defines the parameters within which detailed decisions can be made about design and specification. These more detailed decisions – within defined choices – can be made by the future residents and were split into two types. For example, the building groups had to collectively decide on the design of the community spaces, entrances and stair-wells within their block and could participate in the selection of standards, materials and equipment. Groups are assisted in this process by the architect and by the Baubetreuer, who feed their views into the development process and budget. Individual building group members were then able to specify the layout and material finishes for their own homes within the parameters voted on by the group. They worked directly with the architect to do this and had to confirm their choices by signatures at key deadlines. This prevented endless changing of minds, and kept the development process on track.


  • 2006 Hamburg city council begins a residential development programme – which it calls ‘Metropolis Hamburg – The Growing City’
  • 2007 The city signs a cooperation agreement with local and regional housing providers to make land available to them with option periods (“Anhandgabe”). There is a strong development brief and – for some plots – a condition attached meaning developers have to work with building groups
  • 2008 Altoba tenders for the site at Kleine Bergstra?e and the first ideas are formed in collaboration with the building groups
  • 2009 City finalises the detailed planning brief (“Bebauungsplan”) for the site, within which Altoba submit an application for a building permit on behalf of all the project participants
  • 2010 Altoba receives a conditional permit, and outstanding issues relating to access and land-use classification are resolved in late 2009 and throughout 2010
  • September 2010 Altoba receives a revised permit and is able to proceed
  • November 2010 Construction begins on site
  • July 2012 Practical Completion; residents move in – first apartment handed over on17th July 2012 at a ceremony with Hamburg Senator Jutta Blankau
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Further Reading

Duneland Ecovillage, Scotland   Projekthaus, Potsdam   Cohousing Vinderhoute and other Cohousing projects   Spreefeld Genossenschaft, Berlin   Kalkbreite, Zurich   Group Projects in Strasbourg   Elf Freunde, Berlin   Alte Weberei, Tübingen   Nieuw Leyden, Leiden   Aspern Seestadt, Vienna  


The NaCSBA Research & Development Programme is funded by the Nationwide Foundation and aims to promote the self-build and custom build sector as an affordable route into housing for a greater number of people in the UK. For further information, please or
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