Tennis is enjoying immense popularity. That holds true for Switzerland in particular. – Not only since the Swiss tennis star, Roger Federer, has been flying the flag for the Alpine nation throughout the world. The very good infrastructure is certainly one of the reasons for the prestige of tennis in Switzerland. Modern indoor tennis courts are springing up all over the country, allowing people to play all year round. One of them has just been finished, the Sports Core Belpmoos, near to Bern.
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Three-section roof structure
The new tennis complex is large enough to accommodate five tennis courts, guest commercial areas and conference rooms. Two tonne roofs with a total area of 5000 m2 protrude above the structure. They are supported by a solid wooden construction. An elastomer bitumen sheet was first tensioned as a vapor barrier on the wooden formwork mounted on this. 100 mm thick rock wool was then laid over it as heat insulation. To guarantee the tightness, a 1.8 mm thick plastic sealing sheet made from PVC was finally laid.
Everything from a single source
The laying company Gyger Flachdach AG was entrusted with the task of providing the roof structure on this complex building. Leister machines were used for all welding work. Mr. Heiniger, Gyger Flachdach AG: “Leister machines have proven exceptional once again. It is especially important for us to only need one device supplier for the various work and materials. That saves a lot of time and effort for providing training on the new machines while reducing the availability during service work on the devices. What is more: the Leister sales partner is also a real help for advice directly on the roof.”
The BITUMAT B2 from Leister was used for the lowermost layer of the triple layer roof structure. This is the only hot air welding machine to have been developed specially for machining elastomer bitumen. Processing the bitumen sheeting with a naked flame on the wooden base was not possible at the tennis center in Belp for reasons of safety. The BITUMAT B2 working with hot air was more than an alternative. It is the perfect solution in every respect when welding bitumen sheets and has really proven its merit on this roof.
Economic work and homogenous weld seams
The use of a hot-air welding machine is not only much safer than working with a naked flame, it is also more economical. Two work steps, heating and pressing, are necessary when welding with a naked flame. Only one work step is needed with the BITUMAT B2. That means its use pays off quickly, especially seeing that it provides a working power of maximum 12 m/min. However, the welding speed was only 5 m / min owing to the challenging nature of this steep roof.
The outlet temperature at the high-performance nozzle was 620°C. The welding result itself was significantly better than with a naked flame. The BITUMAT B2 produces homogenous, absolutely tight seams with a high weld strength. Even on the arched roof structure, the BITUMAT B2 did not pose any difficulties for "climbing" the inclines. The machine can be kept on course easily by gently correcting the height-adjustable and swiveling guide rod.
The ideal complement
Hot-air welding machines from Leister were also used for processing the plastic sealing sheets – the VARIMAT V2 and the UNIROOF E. The two complement each other perfectly and solve every problem when it comes to machining plastic sealing sheets. The powerful VARIMAT V2 is above all suitable for large roofing areas with its working speeds of up to 12 m/min. The small and handy UNIROOF E is useful for edge seams and poorly accessible areas for which the VARIMAT V2 is too large. The VARIMAT V2 was used for the flatter areas and the smaller UNIROOF E for the highly steep points and transverse seams on the roof of the tennis center. A reliable weld was also especially important here, because the two meter wide plastic sealing sheets are exposed to a high wind load on the bare roof.
With good reason, the tennis aces now playing in the indoor court expect to play under a dry roof all year round. For the laying company Gyger Flachdach AG, On the other hand, the use of a triple layer roof structure posed a real challenge. Mr. Heiniger again: “We’re more than satisfied with our work. The Leister machines allowed us to cover the 5000 m2 roof fully watertight in a short time and without interruption.”
Object: Sports Core Belpmoos AG, Belp, Schweiz www.sportscore.ch
Building owner: Renova 2000 AG
Laying company: Gyger Flachdachfirma AG, Heimberg, Switzerland www.gygerflachdach.ch
Machine supplier: Leister Process Technologies, Kägiswil, Switzerland www.leister.com
Leister sales and service partner: F. Jannone AG, Wabern, Switzerland www.jannone.ch
Author: Christophe von Arx, Leister Process Technologies
Photos: Jannone AG / Roland Beeler, Leister Process Technologies