The former fire station is a listed building, which was built in 1926 by architect Franz Baumgartner in the style of the architecture at the lake Wörther See. It is now used as a music school. The building is characterised by its strongly articulated gates on the main street façade. The large roof area is broken up by an enormous front gable. The building comprises two full floors, an attic, a partial basement and a turret room. The market town of Velden am Wörthersee implemented a comprehensive thermal-energetic renovation of the building. This renovation was carried out within the framework of the demonstration programme “Mustersanierung”. The innovative measures and the project documentation were funded by the Austrian Climate and Energy Fund. The building achieved the klimaaktiv GOLD standard, an Austrian rating system for the sustainability of buildings.
The box-type windows, the façade and (partly) the standing construction were worthy of preservation, as well as ceilings, stairs, floors and the interior decoration (wooden ceiling, windows and doors, terrazzo floor). - The wooden ceiling was removed at the edge in order to guide the interior insulation upwards without thermal bridges. The ceiling was then shortened and fitted. - The profiles of the windows were partially copied in order to achieve the technical standard. - For the terrazzo, an optical compromise (width of the border reduced) was necessary due to the interior insulation. - The ventilation was integrated into the historic wooden ceilings (only existing openings were used). - The ceiling doubling for room acoustic separation was carried out in a way that was clearly readable in terms of design.
Aim of retrofit: The aim of the renovation was to ensure that the building meets the contemporary standards of a music school and can be used multifunctionally for various events, seminars and associations. As an e5 community (program for energy-efficient communities in Austria), Velden has a great awareness of sustainability. As a result, the planners were asked from the beginning to think comprehensively about sustainability and to optimize energy efficiency. The logical conclusion was to take part in the funding program "Mustersanierung" (model renovation). The financial support was facilitating but not decisive. The objectives of the renovation were the ecological use of materials (80 % eco-label products), reaching the klimaaktiv Gold certification and a chemical management ("healthy learning spaces for our children").
The façade was restored on the outside and adapted to the original colour scheme for reasons of monument protection. On the inside, the thermal renovation was executed with an internal insulation in the form of 8 cm calcium silicate boards, whereby care had to be taken that the existing construction would not suffer any damage in the long term.
The adaptation of the façade to its original condition and the choice of thin insulating panels on the inside of the exterior walls ensured to preserve the original character of the building. Also, Calcium silicate boards were selected as insulation material with regards to protection of historical monuments, ecology and summer overheating protection.
- U-value (pre-intervention) [W/m2K]: 1,18 W/m²K
- U-value (post-intervention) [W/m2K]: 0,38 W/m²K
HVAC: It was the conversion to 100% renewable district heating, for which proof of delivery was requested. The heat delivery system consists of underfloor heating on the ground floor in the area where the floor structure was redone, and radiators on the upper floors. In addition, a comfort ventilation system (2 units, 1x for the hall and 1x for the classrooms) with heat recovery was implemented.
For the comfort ventilation system, the fresh air intake and exhaust air discharge was carried out via the historic chimneys, as this was not possible on the facade.
Renewable energy systems: The new PV is situated on a part of the buiding with a flat roof. The average yield of the PV system is about 10,000 kWh per year, of which about 40% is consumed in the renovated building and the remaining electricity is passed on to the neighboring doctor's office.
The PV was installed on the part of the building, which is not under conservation.
Further information on the case can be found here.