Smooth curves for the lace museum in Calais
Although the double skin point-fixed structural glazing structure is modest in size, many difficulties are concentrated in it. The biggest difficulty is manufacturing of double curved laminated glazing forming bubbles, with a liquefied appearance that seems to match the physical properties of the water in the canal running alongside the museum. Many different moulds were used, because every glass panel was different. Furthermore, the increase in the strength of glass by quenching was difficult to implement uniformly.
Jean-Pierre Tahay, Department Manager at Viry, the contract holder, explains that problems with the tolerance between the glazing and the secondary structure composed of Welded Built-up Sections created a second challenge to be solved: "An attachment system was specially developed for the operation. Glass panes forming part of the inner skin and the outer skin are clamped in pairs by means of fasteners welded onto PRS (welded Wide Flange – WWF) members. These fasteners resist the self weight of the glazing and wind forces, and include a vertical articulation system with inserts that allow movements of the member and glazing deformations."
The history of a craft and a town in a facade
The silk-screen printing was a third symbolic and technical challenge. The architects, Alain Moatti and Henri Rivière, asked lace-makers to produce punched cards similar to those used to make lace using cast iron leaver machines. The patterns of these punched cards were scaled and reproduced on the inner face of the outer skin of the double skin, by silk-screen printing using aluminium grey metallic components, for better reflection of light from the sky.
Finally, Jean-Louis Galéa, CSTB manager for the Technical Experimental Assessment, reports that a hygrometric study was carried out to calculate temperatures and to reduce risks of condensation in the air gap in the ventilated double skin. "Wind strength tests were also carried out, not only on the outer skin, but also on the inner skin, he says. Unlike what would be expected at first sight, the inner skin has to resist higher stresses due to wind forces than the outer skin, although the outer skin is the most highly exposed."
- Client: SEPAC, ADEVIA for the town of Calais
- Project management: MOATTI & RIVIERE, architecture agency
- Structural engineering design office: RFR
- Inspection office: SOCOTEC
- Manufacturing of plane and curved glass: SANXIN GLASS TECHNOLOGY
- Design and placement, secondary frame: VIRY
- Planned delivery: June 2009
Interview with Henri Rivière, architect
Henri Rivière, how can you define your work?
Architecture for us is the search for imaginary places. But it must be feasible to materialise these imaginary places to make them a reality …
But how can this imagination be fed and anchored to reality?
Through the link. By meetings between people, and particularly with the client. If the link is strong, the client and future users will carry the imagination and the dream. They will extend it and accept it. An understanding of the location at which we work is another important aspect of our work, both for retrofitting and for new construction. A place can be led towards the future by correctly understanding the social, economic and urban context, and its origin and history. This future is based on a poetic, almost phantasmagoric search derived from our convictions and our culture. Finally, we believe in places with a strong identity. We always return to the places that we have loved. We maintain them. But if we are to love and maintain them, they must trigger some emotion, and encourage us to travel. This is why I am talking about the imagination.
And for the Calais lace museum?
Lace was the economic driving force for the Town of Calais, and then the activity dwindled. There are now only 2 000 lace workers, while they were 60 000 during the 1960s. A visit to the last lace workshops conjures up visions of the middle of the 19th century: the noise of large 12-meter long cast iron machines lubricated with graphite fills the space at a maddening rhythm. The hands and faces of workers are black. The floor is black. But these machines produce the most beautiful lace in the world. The project was designed to render homage to the extent of this lace craft, for which training takes about 10 years. The best way of rendering homage was to work with contrasting materials and to create a strong relation between existing and modern buildings. It was important to identify a language between raw materials and other more highly worked and valuable materials. We superposed a very avant-garde architecture with a sensual façade constructed using a double curvature silk-screen printed glass, onto an existing dilapidated factory, to extend its life by a few more decades. This is a metaphoric way of talking about the lace industry and the desire that it incites.
Did you already have the bubbles idea at the competition stage?
Yes obviously, but glass did not spring to mind immediately. For the competition, we had hesitated between metal and very high performance concrete, but gradually we moved towards glass. But obviously, this was only possible if we had partners capable of merging the engineering and architecture: Philippe Bompas and Nicolas Prouvé, from RFR
How are the internal spaces organised?
The modern extension is reserved for temporary exhibitions and a 250-seat auditorium on the first floor. The ground floor of this extension includes the reception, cafeteria, the media library and educational spaces. In fact, we inverted the urban orientation of the building. After the extension, the back of the old factory became the front of the new building facing the canal. This participated in creating a new urban centre that could be provided by the canal. But inside the museum, the visitor has to pass along the contemporary extension before approaching the heart of the subject in the old factory that we have rehabilitated and that contains all the permanent exhibitions.
What is still left of the history of the old building after it has been rehabilitated?
The industrial character that we kept does not hide its scars and its origins. Its existing composite structure composed of brick walls and cast iron columns supporting softwood beams and pine block column supports, allowed some flexibility to absorb machine vibrations. Our work consisted of reinforcing this structure and bringing it up to modern standards without changing its character. Museographic research was based on the same principle. The objects and exhibits are presented in an industrial setting. The air treatment ducts, cableways and lighting systems are visible. Once again, there is a sort of contrast between what already exists and the elements that we have added on.
Is this enough for the building to maintain some sort of industrial truth?
Not really. The museography was designed as a living workshop in which the visitor walks between the running machines. There is a cultural and economic message for this old factory that was still working only eight years ago. We wanted to show that there is still a breath of life in the building's activity, and that a museum can also be a living place. There will be a functioning lace manufacturing workshop in the museum that will be capable of producing creations, with the assistance of designers, seamstresses and stylists.