Page 1


Redesign Studio I Facade fragment


September 2011-February 2012


Photo of the building complex


Redesign Studio I Facade fragment


September 2011-February 2012


THINKING INSIDE THE BOX Project: Redeisgn studio of a facade frgment _ Building Westravent in Utrecht Tutor: Hans Nout The Westraven building, designed by the architects Lucas & Niemijer, and then renovated by Cepezed Architects, accommodates the Dutch Department of Public Works. The program of the building includes office spaces, conference facilities, a national meeting centre, a communications centre, and the Future Center for the Department of Public Works This project deals with the redesign of the Westraven complex in Utrecht and especially with the ETFE façade of the entrance area, as it tries to improve the insulation of the building while maintaining at the same time it’s transparency. It cannot be denied that the redesign of the Westraven by the Cepezed architects is considered successful at a great degree. Nevertheless, there are still some features to be improved regarding the therml performance of the building.

Top left Plan of the Westraven complex Bottom left Plan of the Westraven building Top right Photo of the entrance fragment with the ETFE foil Bottom right Front facade of the low rise building of Westraven. The colour indicates the ETFE facade that is redesigned

THE ENTRANCE AREA Regarding the entrance area the materials used for the cladding of the façade and roof show low thermal insulation properties causing a green house effect. What is more, due to the fact that this area is also used as a presentation area, the façade often generates light control problems, as it does not include a sufficient shading system in order to control the amount of light entering into the building. The challenge of the project was the redesign of a sunshade system that could be easily adjusted to the existing building. Main intention of the redesign was the maintenance of the idea of transparency that this building stands for. Therefore the research question is formulated as following: “How a sufficient and simple sunshade system can be added to this already existing façade and roof structure in such a way so that the appearance of the building can stay intact. And how can the insulation of the building be easily improved while maintaining the transparency of the ETFE facade”.

Photo of the facade framgent

SIMPLE SOLUTIONS The proposal is about a double-skin façade that is consisted of a double ETFE cushion system at the exterior part of the façade and a single glazing at the interior. The ETFE cushion has imprinted overlapping shading patterns, acting as a sunshade system while the glazing will create a natural internal – external division to prevent the overheating of the building. The air trapped between the cavity of the ETFE cushions and the glass acts as an additional insulation for the building. Openings at the glass of the façade and roof construction achieve a better ventilation of the atrium during the summer and winter months. Regarding the cushions, the operating system is the same with the existing one. Air pumps hidden inside the columns of the structure supply the cushions with air. The same system alters the amount of air entering into the cushion, thus increasing or decreasing the opacity of the pillows. In this way, the overlapping shading patterns that are imprinted onto the ETFE foils can change the amount of sun entering into the building. This depends on the distance between the two ETFE layers as well as on the angle of the sun.

FOR DIFFICULT PROBLEMS the trapped hot air is not entering into the building but is released outside in order to help cooling down the building

the two layered ETFE membrane acts as a sunshade system preventing the sun from entering the building

the 3rd layer of glass acts as the internal-external division and operats according to the principles of a double-skin facade

REDESIGN PROPOSAL >> a double ETFE pillow system with overlapping sunshading patterns imprinted on their surface is proposed >> a single layer of glazing at the inside part of the facade will create a cavity where the hot air will be trapped >> controlled air pressure will adjust the opacity of the pillows thus adjusting the amount of sun that will enter the building

MATERIALIZATION & DETAILING Furthermore the shape of the patterns has been designed in a way so that it doesn’t alter much the basic design intention of the facade.


As for the internal part of the atrium, the additional glazing creates a cavity of trapped air, which is used for the insulation of the building according to the different external climatic conditions. In this way, there is created an interior shell made out of glass – a glass box inside the ETFE cushion box. These two structures when combined together, can lead to a better control of the inside climate of the fragment. Taking into consideration the glass weight that has been added to the structure after the redesign, a second load bearing system has been designed similar to the existing one that can strengthen the structure of the atrium. Slender beams and columns of similar dimension with the existing ones are added to the structure. in different levels of the structure.

Photo of the entrance area


[Kees Kaan & Henri van Bennekom]

main steel beam which holds the ETFE cushions additional beam for the glass frame

supporting structure: steel box column, 8x50cm, which also functions as the air supply for the ETFE air cushions additional steel column ETFE air cushions with imprinted sunshade patterns steel corridor from orsogril which is used for the cleaning of the facade 3D veiw of the current structural system 3D view of the redesign’s structure

3D veiw of the redesign proposal

Top left Detail of the vertical section between the already existing structure and the additional one. Bottom left Detail of the horizontal section where the new and the old structure is connected Vertical section of the facade


Exterior view of the facade

Interior view of the facade

Westraven project