SWISSPACER Viennese muntins ensure that both energy requirements and conservation recommendations are met
Work to restore and modernize the window frames at the New Palace in Stuttgart continued until the end of 2021. The company involved in the project, Holzmanufaktur Rottweil, attaches great importance to traditional craftsmanship in harmony with modern requirements for building energy efficiency. For this reason, it has opted for a stylistic element in the form of SWISSPACER's Viennese muntins, which additionally affect the UW value of the windows.
The new Stuttgart Palace, located in the heart of the Baden-Württemberg capital, boasts a long history. Construction of the building lasted in several phases from 1746 and was not completed until 1806. As a result of air raids carried out in the spring of 1944, the palace was almost completely destroyed, with essentially only the facade surviving. Since its reconstruction after the war in 1958-1964, the building has been used by, among others, the Baden-Württemberg government and other state institutions.
The new Palace in Stuttgart
© Swisspacer
The palace consists of two stories and a mezzanine - partly in the form of a mezzanine behind a uniform facade, and partly in the form of a mansard covered by a sloping roof. The classical facade with strings of window openings includes rectangular windows, windows finished with semicircles and sharp arches, as well as round windows in dormers. In 2019, the state of Baden-Württemberg, represented by the "Vermögen und Bau Baden-Württemberg" office in Stuttgart, issued a tender for the renovation of the wooden window elements and replacement of the glazing in the sashes facing Planie Street and the rose garden. The scope of the project included upgrading some 530 windows. The glazing area of the windows, some of which have up to four sashes each, is about 1,700 sq. m.
The art of conservation
Holzmanufaktur Rottweil was chosen as the contractor for the work. The company, headquartered in Baden-Württemberg's oldest city, has been involved in woodworking for historic and legacy preservation and architectural projects for more than 30 years.
The New Palace in Stuttgart
© Swisspacer
We restore and repair historic furnishings such as windows, doors, floors and paneling. Historic quality gets a contemporary twist, whether it's restoration, repair or restoration," is how Adelina Bytyci-Dodolli, the company's attorney, talks about its philosophy.
Holzmanufaktur Rottweil, founded in 1988 by two general managers Hermann Klos and Günther Seitz, today employs more than 100 people in carpentry, glazing, painting and administration.
Since, in many cases, windows, doors, stairs or floors that are not fully operational require improvements in terms of thermal and acoustic insulation, as well as safety, satisfactory compromises had to be found in terms of the craftsmanship techniques used, emphasizes sales manager Karsten Braun. - If the scope of the changes is too extensive or the task is approached with insufficient sensitivity, renovated elements can easily lose their historical character. Preservation and restoration must not mean stopping at a certain stage, let alone technical regression.
This statement also applies to the extensive repair and restoration of wooden windows at the Stuttgart Palace, which Holzmanufaktur Rottweil began in 2019 and completed in 2021. The extensive project consisted of upgrading the wooden elements and hardware of the historic windows.
Our tasks were very diverse," explains Karsten Braun. - The primary goal was to meet the energy requirements for a building used as the headquarters of administrative bodies, while at the same time taking into account conditions arising from historic preservation.
Accordingly, the investor decided to retrofit the existing single-glazed windows with insulating double-glazed units from the outside.
Also important was the fact that the work could only be carried out from the outside and without the use of staggered scaffolding, which would have involved advanced logistics, Braun stresses. - The restoration included careful machining and painting, as well as repairing the window frames, and replacing gaskets, glazing beads, etc.
The new Palace in Stuttgart
© Swisspacer
Aesthetic appearance of Viennese muntin bars
A special feature of the project was the installation of special insulating or solar control double-glazed units in the mansard windows. These were fitted with Vienna muntins.
Our choice was Vienna muntins from SWISSPACER," says Karsten Braun. - Their appearance is in line with our concept, and an additional advantage is the availability of many colors. At the same time, they allow us to meet all energy requirements. The investor wants the warm frames to be installed in a way that is practically invisible - that's why it was so important for us to choose the right colors. In addition, with SWISSPACER elements it was possible to maintain the required restrictive aesthetics of perfect corners.
Another important criterion for the Holzmanufaktur Rottweil team was the seamless fit of the muntins to the building's windows. SWISSPACER now offers 13 different sizes of Viennese muntins, complemented by a cross connection with an integrated spreading plug. In the case of the mansard windows in the Stuttgart Palace, the required element width is 10 mm. SWISSPACER Vienna muntins are made of the same highly insulating plastic as the manufacturer's spacers, which were also used in this project (SWISSPACER Advance model). They make it possible to minimize the occurrence of thermal bridges at the edge of the glass. For the palace in Stuttgart, it was possible to achieve a glazing Ug value of 0.9 to 1.0 W/m²K.
The new Palace in Stuttgart
© Swisspacer
The renovation work carried out at the building by Holzmanufaktur Rottweil proceeded on schedule. The use of Viennese muntin bars made it possible to reconcile conservation requirements with exceptional energy efficiency, so that the investor, designers and the contracting company were fully satisfied with the results.
For more information, visit the company's SWISSPACER page on the A&B portal.
