Ecological restoration of a listed building with passive house technologies

Status

completed

Summary

The building of the Haidenhof was originally constructed as a coaching inn. In the year 1870 it was adapted to a residential building and after some modifications in the 1930s it became its today appearance. After the death of the last owners the building and the site became property of the community Bad Ischl. Despite of some minor restoration works the state of the listed building deteriorates noticeably.

A comprehensive renovation and revitalisation of the building structure are as urgently necessary as a sustainable concept for developing the site. The present research study therefore provides the basis for an ecological exemplary renovation using passive house technologies.

The special challenge lies in the restoration of a listed building with passive house technologies on one side and the architectural implementation on the other side. The implementation is based on the development of a sustainable and forward-looking concept for the site.

In a first step the concept for the site, that takes into account a floor area of the building of 2.500 m² and a green area of app. 40.000 m² in favourable location, was developed. A local, multifunctional centre for art and cultural oriented, supraregional institutions shall arise which is used also for education and training. The institutionalisation of an art and culture academy is intended for the inner "Salzkammergut" which includes besides painting, operetta, play and cabaret also the option cookery or wine culture.

Based on extensive preparatory studies different renovation variants for the Haidenhof were finally defined and assessed by a thermal building simulation.

The following three main variants were selected for the renovation of the solid building parts:

1. In the variant "existing building" it is assumed that only the not utilisable components like the decayed roof truss and the lightweight walls of the building are replaced by constructions that fulfil the building regulations.
2. In the renovation variant "exterior insulation" the limestone walls in the ground floor and upper floor are covered with 20 cm insulation at the outside and with a thin insulation at the inside of the ground floor. The roof truss and the lightweight walls are carried out in constructions that are suitable for passive houses.
3. In the renovation variant "interior insulation" the limestone walls in the ground floor and upper floor are covered with 8 cm vapour-tight insulation at the inside. There is no insulation on the outside of the wall. The roof truss and the lightweight walls are carried out in constructions that are suitable for passive houses.

In the thermal building simulation a heating demand of 150 kWh/m²a was determined for the existing building.

For the thermal and technical optimal renovation with exterior insulation the heating demand was reduced to approximately 24 kWh/m²a by using a high efficient air heat recovery.

In the case of the renovation with inside insulation that the monument protection authority prefers the heating demand can be reduced to approximately 38 kWh/m²a with a high efficient air heat recovery.

To supply the renovated building with renewable energy we suggest a wood-pellet heating. One boiler should be equipped with a stirling motor for the production of electric energy. We did not continue to pursue a planned solar thermal system because the monument protection authority objected to it.

The very low cooling demand which was calculated in the thermal building simulation is covered largely by ground heat probes.

Project management

DI Wilhelm Hofbauer
Arbeitsgemeinschaft Hofbauer Mühling

Project collaborator

Arch. DI Friedrich Mühling, DI Fritz Zierfuß, Hans Zelenka, DI Roman Smutny
Arbeitsgemeinschaft Hofbauer Mühling

Project or cooperation partner

• Univ.Prof. DI Dr.rer.nat. Jürgen Dreyer, Ao.Univ.Prof. DI Dr. Thomas Bednar, DI Dr. Clemens Hecht, Tanja Höfer
  TU Wien, Institut für Hochbau und Technologie
• DI Dr. Thomas Mach, DI Markus Michlmair, DI Dr. Hermann Schranzhofer, Ao.Univ.Prof. DI Dr. Wolfgang Streicher
  TU Graz, Inst. für Wärmetechnik, Arbeitsber. Energieeffiziente Gebäude
• Ao.Univ.Prof. Mag. Dr. Philipp Weih
  Universität für Bodenkultur Wien, Institut für Meteorologie
• DI Markus Brandl
  architektur bau projekt gmbH, Salzburg + Bad Ischl

Dipl.-Ing. Wilhelm Hofbauer
Penzinger Straße 58, A-1140 Wien
Tel.: +43 (1) 8943191-13
Fax: +43 (1) 8943191-15
E-Mail: technisches.buero.hofbauer@utanet.at