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Royal Museum of Fine Arts in Antwerp

The waterproofing works on the roof top of the Royal Museum of Fine Arts in Antwerp (KMSKA), Belgium have been completed. 1,665 m2 of white single-ply waterproofing membrane, perfectly cut to size to be installed around 198 different-sized triangular skylights. A complex task with a magnificent result: a roof that is a true masterpiece and allows natural light to enter the museum’s rooms.

The restoration work on the roof of the Royal Museum of Fine Arts in Antwerp (KMSKA), Belgium, has been completed with single-ply waterproofing membranes. The result could only be a masterpiece of architecture and design for this 19th century neoclassical building, where about 7600 works of Flemish art are housed, including paintings, sculptures, drawings and prints. It can be said that today the roof of the museum is already a work of art in itself, thanks to the 198 triangular skylights fully waterproofed with 1,665 m2 of white waterproofing membrane, cut to size to perfectly cover every surface. The Antwerp Royal Museum of Fine Arts is scheduled to re-open in 2021.

The ambitious project to renovate and expand the Royal Museum of Fine Arts was conceived to transform the former internal courtyards into a new vertical museum area. Thanks to the construction of an area dedicated to contemporary art within the ancient walls of the building, the museum now houses two artistic worlds that are distant from each other yet equally fascinating.

It was to protect these precious masterpieces that a solution was sought that could offer the exhibition rooms as much indirect and northern light as possible. So, the Claus en Kaan firm of architects thought up an ingenious design for the roof. In addition to being of great aesthetic impact, the 198 triangular roof skylights are built to allow the northern light to enter the museum's rooms. In fact, the north facing windows allow indirect lighting, thus avoiding any compromise between visual experience and conservation of the art on display.

Hence, the architects' choice of the entirely white single-ply waterproofing material. These characteristics allow the sun’s rays to be reflected to the maximum, an effective way of improving the quantity of indirect light coming through the windows and provide additional internal lighting. The membrane also helps to reduce excessive heat in the building during the summer and, as a result, energy consumption due to air conditioning.

Another advantage of single-ply waterproofing material is, without a doubt, its flexibility. It was a difficult task for the ADCO team of installers who were responsible for renovating the roof of this new building. It took time and considerable technical skills. All 198 skylights were prefabricated off-site, one by one. Then the 198 triangular wooden constructions were covered with single-ply waterproofing material, and to assure a perfectly waterproof and neat finish, metal sheet profiles were secured to the edges. Lastly, each triangle was covered with the single-ply waterproofing membrane. 1,665 m2 of membrane cut to size into different small sections, to perfectly fit the skylights, which are also of different sizes.

A flat roof always slopes slightly to allow rainwater to drain off. That is why three different sizes of skylight were used. Even a slight slope would have interrupted the optical effect of a straight line formed by all the peaks of the skylights.

Project participants

Owner: Koninklijk Museum voor Schone Kunsten Antwerpen Lead Architect: Claus en Kaan, Amsterdam, The Netherlands

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