Two residential towers in the De Caai project in Eindhoven are getting special facades. The most striking feature is a large facade with a bar at the bottom. Reynaers Aluminum constructed this unique facade and demonstrated that it meets the high requirements for air tightness, water tightness and wind resistance.
The first two residential towers of the De Caai project differ in design and height. Both were designed by Mei architects and planners and built by Huybregts Relou and Van Oorschot Aluminum as facade builders. The two towers of 18 and 24 floors each have their own challenge in the facades. The facade of the lower tower is built in the flat system ConceptSystem 77 (CS77) from Reynaers Aluminium, whereby a large window will also serve as access to the balcony. It will have an adapted low ground profile for this purpose. The taller residential tower will have a facade in the SlimLine 38 (SL38) steel look system. In this facade, there are large fronts with a pole at the bottom.
It had to be demonstrated for both special solutions that they met the requirements for water tightness, air tightness and resistance to wind load for the classes of 60 and 75 meters respectively in an unbuilt area. To this end, Van Oorschot Aluminum built test models that were tested and certified at the Reynaers Aluminum test center in Duffel, Belgium.
Water to a point
Reynaers Aluminum could theoretically demonstrate in advance that the window in SlimLine 38 with the bar at the bottom complied with the test values. But the shape of the window was so unique that Reynaers built a test model together with Van Oorschot Aluminum to optimize it, says development expert Mike Snoeijen. He first asked if Reynaers had international experience with such a facade, but it turned out that there was none.
Making the bar itself wasn’t the problem. The curved shape is more common, but usually always at the top. The big challenge with a curved frame is that the water will drain to one point. “Based on our knowledge and experience, we constructed this element on paper and made production drawings. Van Oorschot Aluminum has made a test model which we have tested and optimized. Normally the spaces between the posts are separated from each other for drainage. We have now completed those courses. We have adapted the drainage scheme to the different shape of the bottom rail.” With these adjustments, the facade met the requirements for use in the residential tower.
For the second tower, the window with lowered bottom profile was tested. With this profile, access to the balcony is simplified, while the window still retains the appearance and fittings of a window. The ground profile had been used before, but had not yet been tested for use at height.
Due to the height of the towers, there were strict requirements for water and air tightness and resistance to wind load. For air tightness it was class 4 (600 Pa). Requirements were made for watertightness of 310 and 330 Pa, respectively, and for resistance to wind load of 1200 and 1260 Pa.
These requirements partly differ from the usual certification classes, says Snoeijen. “For waterproofness you have class 7A up to 300 Pa. The next class, 8A, is up to 450 Pa. For resistance to wind load you have class 3B: class 3 is up to 1200 Pa and B a deflection of 1/200. To next class, for example, you have to use heavier profiles, with additional costs. The requirements in this case were only just above the class limit. Therefore, we have chosen to test up to the requirements. You test the waterproofness in steps. You start with 15 minutes of watering without pressure and then one step higher every five minutes. After achieving class 7A for water resistance, we tested for another five minutes at 310 and 330 Pa respectively. The same applies to resistance to wind load. For the lowest tower, class 3B – 1200 Pa – was sufficient. For that highest tower, we went one step further to 1260 Pa.”
These test results are certified by SKG-IKOB. With which Van Oorschot Aluminum can demonstrate to the client that the facades also meet the requirements with these project-specific solutions.
Location: De Caai, Eindhoven
Builder: BPD Area Development
Design: Mei Architects and Planners
Main contractor: Huybregts Relou
Facade builder: Van Oorschot Aluminium
Systems used: ConceptSystem 77 and SlimLine 38
Construction start: 6 July 2022
The Practical case section is a collaboration between a manufacturer and Bouwwereld. On these pages, the manufacturer shows how a product or service is used in a project and how he can collaborate with construction engineers, constructors and/or architects.
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