On the construction site of the highest residential building far and wide is worked diligently. It is barely visible from the outside. Currently, the interior fittings are removed. Nevertheless, the build version is out – an expert opinion is missing.
Fellbach – The Fellbacher tower is progressing, even if you do not see much progress in construction on the outside. According to his boss, Christoph Gröner, investor CG Group is about to lease this 164-room hotel located at the foot of the 107-meter-high tower. "We have a clear commitment from a well-known hotel chain," said the project's chief developer. He does not want to give the name yet.
The old building in ruins is actually another construction site
Even otherwise, the exterior impression of an abandoned construction site is misleading. This is no longer the case for several months, according to George Moutoulis, governor of Gröner in Stuttgart. The sloping roof on the 34th floor was sawn, which was particularly worrying for the energetic Christoph Gröner for visual reasons, but also for the creation of two other apartments. Some citizens may not have noticed this deconstruction as clearly.
The old building in ruins is in fact another construction site: inside, works diligently, declares George Moutoulis. Thus, it confirms that, due to the transformation of the apartments, all lines already installed by the previous owner, partitions and sanitary facilities, up to the 18th floor, have been removed. Finally, instead of being initially planned, two or three future apartments will be installed on one floor. To achieve this, and nevertheless to offer each tenant a "living environment", according to Mutoulis, all the skyscraper must become what it is already in the upper floors: a construction in shell.
Teams made up of 40 specialist engineers were occupied for months
To corry construction is also permitted without the final agreement for the kidnapping and conversion, confirms a spokesman for the city administration Fellbach. The coveted red dot of the Baufreigabe is still missing because the report of the expert asked about the planned conversion is still missing. A Stuttgart office is working on it. The evaluation and publication of the construction works will be further delayed, according to the administration of the city. After all, the members of the CG group have rethought planning before 2012. The skyscraper has been optimized over the past year in ideas, reflections, drafts and negotiations. "In recent months, we have had to deal with static insulation, fire safety and soundproofing of the tower," says Christoph Gröner. This was the beginning of a redesign of the tower in its entirety, even though the building permit of the city of Fellbach had been granted to him. Apartments instead of 66 before. Teams made up of 40 specialist engineers had been busy for months, explains Mutoulis.
Floor by floor, the state was scanned
The new customer specification was to meet the KfW 55 energy standard, which is almost half the energy consumption of comparable buildings. In the national average of its construction projects, Gröner even aspires to a standard that manages one fifth of primary energy needs, a KfW 20, if this standard is already defined. In the old half-finished Gewa tower, with its glass facade, it was difficult: "We have not been able to cope with the most astonishing glasses," says Gröner.
Step by step, the condition was scanned to document it and also to look for a list of references from former general contractor Baresel, which had caused a stir during the insolvency proceedings and deterred a prospective buyer ruins. "We wanted to know what was being built – it was to eradicate every problem of what was a structural flaw in the speech," says architect Jörg Wolf. Because of the 3D data now available, planners could also completely exclude the fact that after converting to smaller apartments, a door might not open or something like that. "We are on a very safe path," said Christoph Gröner.
But the required cooling performance proved to be significant
Transparency helps to plan the construction process. Other construction costs must also be calculated exactly. Among other things, the cooling caused headaches: "If it does not work in high-rise buildings, you can unpack the bath trunks of your apartment in summer," says the subcontractor with a tendency to drastic. However, the required cooling capacity proved to be important and added to the critical energy balance of the building. Thus, regeneration facilities, such as rooftop turbines, had to use the thermal and photovoltaic systems installed on the tower and roof of the hotel. In the future, their electricity will cause cooling from geothermal systems: with the constant coolness of the underground parking, a liquid will be cooled and pumped through pipes to lower the temperature of each floor, if necessary – inverted floor heating therefore, to say. Finally, reflections on the recently announced plan have led to the replacement of the facade next year.
In the second quarter of 2021, the tower is now ready
To remove existing façade elements such as windows and move a little outward, we even tried to do it on two floors. Barely anyone noticed. However, this proved to be vulnerable because of their anchorage, says George Moutoulis. The new facade, with less glass and balconies, but the windows replaced – the old ones are recycled – dramatically reduces the area for heating and cooling from the outside. The entire project, including the installation of new renewable energy plants, will make the extension of the skyscraper more expensive by about 10 million euros, and it will take another six months to build it. In the second quarter of 2021, the tower is now ready. Jörg Wolf from Backnang, architect of the large building largely visible on the western outskirts of Fellbach, does not disturb the planned rescheduling. He even admits that it makes him proud to present the current design of the "reinvented" residential tower. He admires his employer, who takes the necessary funds to "anticipate all the possible technical conditions to fulfill".