Three windows in Paris

PAN architecture is delivering an extension to a 4-star hotel in Paris. The project rounds off a mixed-use scheme, designed by the architectural office Nicolas Reymond Architecture & Urbanisme, that combines social housing and a police station in the ZAC Beaujon business park. While modest in size, the project is ambitious and determined to be special. The independent vertical volume is quietly expressive and fully respectful of the surrounding architecture.
The strict order whichcharacterisesthis neighbourhood creates a strong urban force with its many interpretations of a common theme. Our project seeks to be part of this dynamic harmony through the rhythm, thickness and mineral character of the façade which responds in multiple ways to the architectural heritage around it, while the avantgarde tripartite composition allows for a strong presence, setting the building slightly apart from the others. Throughout the project we have been committed to seeking the best solutions. The highly sophisticated façade is a result of this commitment and lends elegance and refinement.
Apparent simplicity
The project had to meet various challenges. To begin with, there were particular site-conditions to be dealt with. The building was to sit recessed between the existing residential complex and the new social housing complex/police-station, but also above an enormous underground telephone exchange spreading over several floors. It was therefore designed as an independent rigid structure, placed on top. The points of support were predefined and only able to take vertical loads. An ingenious solution was found thanks to the structural engineers from EVP, the loads being distributed evenly using shell beams.
Another challenge was the existing, and still operating transformer on the site that had to be incorporated into the ground floor layout. Ambitious and dedicated to creating attractive public spaces, we successfully made these technical issues vanish into the design.
To connect the new part with the existing hotel we utilised the courtyard in the back, but the floor levels were not the same. An adaptive grid compensating these many variations in height and inherent technical issues assures the harmonious appearance of the facade.
To accommodate the narrow dimensions of rue Laure Diebold, the top two floors are set back (fourth and fifth floors), which is a common way to shape building volumes in this neighbourhood. Thus, outdoor spaces are created, and these balconies and terraces offer a great view. On the other floors, the rooms take their distance from the street by means of a loggia.
Clear distribution and flexible spaces
The layout of the floors is simple. Three rooms line up towards the road joined by a fourth that gives onto the courtyard. Rooms on the top floors are organized as two-storey-spaces. To round off the spatial composition, a multipurpose space has been created on the rooftop. The interiors were not part of the brief.
The notion of tripartition can be found throughout the design. It defines the facade grid, the stepped building volume (one face on the building line plus two recessed faces), the partition of the sash windows and the sliding windows as well as the composition of the ventilation screens.
At the heart of this design exercise was the desire to make a harmonious statement. It hints at a well-known theme in the south of France: the so called “trois fenêtres” (three windows), which was a popular type of tenement in 19th century Marseille. We fancied bringing it to Paris. As it is a tune that comes naturally to southern architects, we decided to play it to the underlying rhythm of the 8th arrondissement.
The simple way in which the rooms are organized goes hand in hand with flexible spaces. Facades and party walls work together to allow for a free plan. Although exceeding the legally permitted building height, the project does so for a good reason: the roof garden with 60 cm topsoil retains water and contributes to biodiversity.
Materiality
As most of the neighbourhood is clad with the local Saint Maximin limestone, we chose black polished concrete in response. Extensive studies and onsite testing were necessary to determine the appropriate dimensions, type of aggregate, shading of the pigmented concrete (pigments, sand and cement), finishing and protection. The contractor in charge (Jousselin) revealed an amazing expertise during this period.
The result is a stone-like material with the mineral, silky texture that only concrete can have. We chose a large format for the precast concrete elements; especially those used on the terraces and balconies of the upper floors. These monolithic seamless concrete plates, that direct all regards towards the roof-scape of Paris and the Eiffel Tower are masterpieces in themselves.
Apart from the concrete, the only materials visible to the eye are glass and aluminium and the common theme for their assembly is the hollow joint.
“Hollow joints draw a fine, distinguished pattern and illustrate clearly how the material is put together. It’s a revelation of the chosen working method and becomes an ornamental element in itself.”
A smart building envelope
The project does not waver under pressure: despite the demand for maximum rentable space (room space) the rooms facing the road all have a loggia. These balcony spaces are conceived as wintergardens, waiting to be seized for different sorts of activities. They serve as a thermal and acoustic buffer zone and improve the room conditions as well as the spatial experience. Enclosed by glass walls with double glazing, these multifunctional spaces in-between become part of the building as the seasons change. They stage a play that accentuate well the dancing rhythm of the façade
We think of these elements as an extension of the interior space into the public realm. Inside these rooms one has the sensation of being projected into the city and particularly so because the frames are hidden and the casements extremely thin. The wish to open up to the city has generated a permeable facade. As the glazing is stacked, the many resulting reflections blur the lines and dissimulate the limits of the building.
Since we wanted to give the building a dreamy expression, we specified minimalist sash windows. This is a common window-type in Anglo-Saxon countries, but rarely used in France. Sash windows are not designed to meet French building regulations and their reputation in France is such that it was quite daring to bring them onto a French building site. We had to obtain several waivers from the local authorities and only succeeded in getting these windows approved – one row on top of the other – due to the support of our very capable client and by working closely with a well-meaning control office. The resulting façade, despite being very modern, plays with traditional design principles and the interstitial spaces are there to be used in innovative ways. It is a showy, jaunty window revealing a high degree of industrial craftsmanship and it was a fascinating endeavour to detail and execute the works. On each side of the window rollers and counterweights are concealed behind the concrete cladding. Only one finger is needed to open these 4 m large glass panes framed by aluminium profiles with a visible width of 2 cm.
As a joint commitment the project proved to be a success as it brought together contractor, architect and client in the quest for quality and the wish to contribute to urban density and variety. The architectural concept is simple: Designed as a plain building in terms of volume, its refinement lies in the details; they tell of craftsmanship and attention to users’ needs and urban surroundings. A delicate piece of “urban jewellery”.

Jean-Luc Fugier, architect