keoto | Architecture, Sustainability, Spandau, D – Berlin

Architecture, Sustainability, Spandau, D – Berlin

Client:Berliner Bau- und Wohngenossenschaft von 1892 eG, Berlin
Project: Integral Retrofit, Sustainability Assessment
Date: 2013


“Large housing developments built in the 1960’s and 1970’s have increasingly become a topic of debate. They are remnants of optimistic visions of the future, in which modern living spaces would be available to all in the vicinity of the city. Due to the simple, standardized buildings with uniform, inflexible floor plans and the allocation policy, the residents of these projects mostly belong to the lower social classes. Years of wear and depreciation of the housing stock aggravated the situation and turned the developments into focal points in the cities.”

While the area does not fully correspond to this gloomy analysis, the “Westplatte” is no prominent building monument, either. However, the neighborhood is representative of its time and is still architectonically important as well as socially necessary. The floor plans are reasonably conceived and the residential mix still corresponds to the current social requirements.

This feasibility study should discern the economic and ecological potential and apply it to the construction, systems and design of the project. In addition to accomplishing zero-CO2 operation, the goal of this development process was achieving a balance between economics and ecology. In order to capture the complexity of the task at hand, an analysis strategy was first developed.


In everyday conversations and discussions between architects and HVAC engineers, the question often comes up, how can one find the best solution for a project from both an economic and an ecological perspective? Does a sustainable solution cost more than a conventional one? What does the concept of sustainability entail and how can this concept be defined in the context of a project?

These broad questions came up during the development of our strategy. KEOTO has devoted itself to the topic and has split the task into to working areas:

  • Working area: “Architecture, building envelope, tenant comfort”
  • Working area: “Sustainability, energy/exergy, heat supply”

The complexity of the task requires a flexible planning system with which the various parameters can be compared to each other. For this purpose, a BIM model of the existing buildings was created. Coupling this model with KEOTO’s tools, it is possible to compare a variety of scenarios regarding energy demand and system deployment.

In the decision-making process, different construction measures as well as various systems were compared to one another, starting from the lowest level of intervention (no additional insulation) to a maximum amount of insulation (addition of 18 cm). In addition to a CO2-free operation, the comparison was based on the contemplation of the total costs over a 35 year period. In total, 5 different systems and 4 different façade variants were examined. It is worth noting that only viable combinations of systems and façade variants were included in this comparison.

This feasibility study compared different solutions so that the most efficient alternative was identified.


The favorable groundwater situation in the area, the proximity to the Havel River and the good architecture in the area favor a renovation based on LowEx criteria. Therefore, the building was fitted with new windows, the roofs and basement ceilings were insulated, while the façades were unmodified. Implementing a new heat pump system combined with hybrid solar collectors is both the most sustainable as well as most economically-favorable solution.

The neighborhood could then be paradigmatic for a new strategy on how to deal with existing buildings. Furthermore, it could become a flagship project to enhance Berliner Bau- und Wohnungsgenossenschaft von 1992 eG’s profile and improve the quality of housing for the residents of the development.