A Quarter Sets its Course for the Future
Guiding Principle – Diversity:
Entries to competitions that form part of IBA 27 should combine high architectural quality, experimental building methods and social and ecological aspects.
This concept envisages a dynamic, socially-mixed urban quarter that offers high-quality design to a range of user groups while retaining the existing trees.
The design seeks to create a transition between the area of small-scale detached houses to the north and the large-scale, high-rise development to the south, while combining these two typologies with the help of an esplanade that crosses the district from east to west.
The urban quality of this esplanade enables it to act as both the entrance to the quarter and a place for meeting outside the buildings. It stretches from Schozacher Straße to the sports pitch and is lined with commercial buildings, social facilities and the kindergarten as well as open areas that can find specific uses at a later stage.
Hence, the esplanade connects a series of places that encourage diversity and exchange – which are essential components for a high quality of life and identification with the quarter.
Typology – a horizontal and vertical garden settlement.
The two typologies of small-scale detached houses and large-scale high-rise buildings make it possible to offer a wide range of types of home that are suitable for people at very different stages of their lives, while also encouraging coming together and a sense of community and ensuring high levels of both identification with and diversity in the quarter.
The design proposes a one to two-storey development in the form of private detached houses of varying sizes that are carefully positioned between the existing trees. Private, clearly enclosed gardens are consciously preferred to a large, inactive semi-public intermediate space.
These intimate, private spaces, into which families can retreat, ensure peace and relaxation, while the esplanade is a central place for coming together and communicating.
With their generous balconies and loggias, the towers, which taper upwards to optimise the natural watering of the planters, can be interpreted as a vertical garden city.
The quarter is accessible to pedestrians from every direction and crisscrossed by a dense network of paths. The east-west esplanade is the main axis of circulation. This is also closed to private cars, as a result of which the entire quarter can be described as car-free.
Cars enter the development via the two entrances to the underground garages from Schozacher Straße and Rotweg. This two-storey garage offers space for 200 vehicles and connects the towers and the small-scale part of the development below the esplanade.
Construction method: Innovation meets sustainability – 62% green space
The hard surfaces on the site are limited to the two towers, the commercial areas and the underground garage.
While the towers were planned using conventional building methods, the small-scale detached houses are designed as light timber structures built from prefabricated elements and placed on point foundations.
This means that much of the site has a very small footprint and large areas are drained by seepage. At the same time, the point-foundation method embodies a very sensitive approach to dealing with the complex roots of the existing trees.
There are many advantages to this timber building method: Firstly, it makes use of a natural material that is largely pollutant-free. Timber is also a renewable raw material with a good ecological footprint that can be recycled and removed without leaving dangerous residues. It also has a low level of thermal conductivity and excellent insulating qualities, which makes it ideal for energy-efficient building.
The roofs of the timber buildings also have simple greenhouses, which are similarly prefabricated and enhance the range of private open space. Hence, each house has a winter garden, which can be used all-year-round while also providing both a daily supply of fruit and vegetables and extra living space between the plants.
Urban climate input
Measurements show that the climate crisis is deepening every year. In order to maintain the quality of urban life in the face of this trend, the adaptation of urban planning and development to meet the challenge of climate change is unavoidable. This means that issues of comfort (in summer and against the wind) and overheating in the city, cold air flows and ventilation must be addressed from the very beginning of any design process.
The objective for the “Am Rotweg” Quarter is to create a forward-looking, climate-fit quarter that offers high quality open spaces and has no negative impact upon neighbouring residents and the urban climate of Stuttgart.
In order to achieve this, the following aspects are relevant:
Cold air flows: The brief addresses the urban climate aspects of the project. This suggests that, when there is a significant level of cold air, the microclimatic system of Feuerbacher Tal provides a flow of cold air from southwest to northeast. When levels are lower, a north-south flow should be expected. Hence, the design ensures that the layout of the buildings guarantees an adequate level of permeability. They form barriers to neither of the two cold air flows described above. This means that any flows of cold air should not be blocked.
Green roofs: Adequate greenery ensures that the roofs do not overheat and that they also retain water. The project envisages numerous roof gardens, open spaces that can also be used during a heatwave. In addition to this, the winter gardens also offer an agreeable open air feeling during spring and autumn as well as winter.
Green façades: Generous planters are incorporated into the two tall buildings. A special feature of these is that, thanks to the pyramidal form of the buildings, all these planters are watered naturally. This increases the probability that they will contain well-watered, healthy plants and have the resulting positive impact on the microclimate.
Seepage across large areas of the site: Thanks to the point foundations, the total area of hard surfaces is reduced as much as possible. This makes a further contribution to minimising any increase in the urban heat island (UHI) effect.
Encourage the growth of trees with large crowns: Only healthy trees with large crowns offer an optimum microclimatic effect in terms of shading, cooling and increasing the level of atmospheric humidity. In order to ensure that trees can mature properly and grow sufficiently, care is taken to ensure that their roots have enough space. Hence, below-ground building work is minimised. In addition to this, the shadows provided by trees with large crowns better counter the heat island effect. Because: the less sunshine that directly strikes the buildings and hard surfaces, the less heat these then give off during the night.
Protect old trees: The value of a large, healthy tree is incalculable. Decades of intense care are required in order to obtain the same positive effect in a new tree. Hence, as many old trees as possible are retained in order to ensure that, even on hot days, as much of the outdoor space offers pleasant conditions for relaxing as possible.