House refurbishment in Munich
The Munich-based architects, Stefan Krötsch and Ruth Klingelhöfer-Krötsch, came across a property advert on the Internet in 2007. They considered the find − a single-family house, completed in 1956, on the outskirts of Munich, which was on the market for a reasonable price − to be a rare stroke of good luck given the soaring property prices in the city. The house, with its three apartment units arranged on two full storeys and an attic level, was one of the larger properties in the street. The Krötsch family decided to retain the house and, with funding available both from the state and the city of Munich, to refurbish it to as close to Passive House Standard as possible. The aim of achieving maximum energy efficiency and a high quality of living on a tight budget set the parameters for the design. Furthermore, the specification of non-toxic materials was a prerequisite for the family with three small children. Thus, all plaster and paintwork in the building is mineral-based, the timber surfaces are oiled rather than sealed, and plastics were avoided wherever possible. There was one notable exception however: the architects chose a polyethylene textile to wrap around the building, which they screw-fixed to a substructure of timber studs and joists. As opposed to thermal compound insulation – which is still commonly used for refurbishments in Germany – if a piece of the PE fabric tears, it can simply be replaced and recycled. The new triple-glazed, larch framed windows are placed into the layer of insulation in front of the existing walls. The architects tried to find ways to save money here too, and used opening sashes only where they were absolutely necessary.
