Urban building

Our challenge was to create social housing that provided a good quality of life in an urban area with rather unfavourable living conditions. The plot is located in a semi-industrial neighbourhood, near one of the major access points to the city of Luxembourg. The side that faces the street suffers from this north-facing orientation, as well as from the noise and pollution caused by traffic. The back of the building, on the other hand, is well lit and enjoys a considerable amount of space.

This compact building stretches along approximately 70 m of city pavement. Its six floors fit in well with the city of Luxembourg’s general urban development plan in terms of size, and the building helps unite its urban surroundings in a way that is well-adapted to a major city access point such as Rue de Hollerich.

It becomes possible to live well on Rue de Hollerich if a large back garden facing south is available, if the flats are double-oriented, and if the first flat to face the street is on the third floor.

In terms of where the different functions to be carried out in our urban building are to take place, therefore, the ground floor will be occupied by shops with well-established street access and by offices with windows overlooking the courtyard. On the first floor, offices will overlook the street, while the first floor of flats will face the garden.

The depth of the plot is 75 m, with a gradient of nearly a story from front to back. By maintaining a horizontal layout from the highest point, we are able to offer not only a large garden and to bring the flats closer to it, made accessible via two footbridges from the first floor of the main building, but also a secondary one-story building, thus creating an inner courtyard which will be enjoyed by the office workers. The car park is located behind the secondary building and under the garden.

We chose to raise the city pavement so that along the side facing the street, it was at the level of our second story. Five stairways lit from the north will provide access to the 40 flats, and will be accessible from the public area just inside the second floor street entrance.

We chose to have the bedrooms face the street, so as to provide large, well-lit living areas fully facing the garden to the south. The rooms overlooking the street have a mechanical ventilation system as well as sound-proof windows, in order to reduce the annoyances due to the location as far as possible.

Two passages with access from two levels lead to the main entrances and the interior courtyard. These match the building’s urban setting and the fact that it is co‑owned, with 40% of flats to be rented out and 60% to be sold.

The façade that overlooks the street is lined with windows and red folded metal cladding. This will be the filter between the public area and the vertical overlay of city life in this urban building (shops, offices, traffic, housing). The façade is simple, aligned with the city pavement because there is no reason, architectural or otherwise, for it not to be.

The metal was chosen for its “self-cleaning” properties and because it will not degrade due to pollution. Architecturally, it is also a strong fit for its surrounding environment. The colour red was chosen partly because many of the traffic lights and signs in the neighbourhood are often red, but also so as to provide a bit of colour in an otherwise somewhat drab neighbourhood.

The façade that faces the garden is covered in natural cedar cladding. Its more formal beauty represents the relationship of the life in the flats located within to the garden: its shadows and its light, the warmth of the sun. This side is not a reflection of its urban role as an entry point into the city, but rather creates a dialogue with the secondary building and garden, thus making room for the courtyard. The geometry of the façade and the large windows also compensate for the lack of balconies, which were not to be included, according to the owner specifications.

The metal structure left us with a lot of freedom to switch between different dimensions and layouts. While carefully focusing on equal distribution, we were therefore able to offer the client flats from one bedroom for one person up to three bedrooms for six people. The metal columns are much thinner than concrete ones would have been, and the fact that the beams were incorporated directly into the thickness of the slabs means that there are no visible lintels as such in the rooms. This is important, considering the somewhat small size of the bedrooms, which are set by the standards governing social housing. High windows that reach the ceiling provide the rooms with a lot of light and also make them feel bigger.

Fire safety was calculated on the basis of natural fire, which means that in strategic places we were able to place metal columns that were not filled with concrete, thus allowing them to maintain their natural elegance.