Wiedikon Residential Building - Zürich - Switzerland
This multi-unit dwelling, located on a busy road in Zürich, was completed in 1938 as part of a block development. Its location close to the city centre provided the motivation to enlarge the building up to allowed limit.
The intervention involved to move the north façade, facing the courtyard, out by one meter.
Formerly exclusively residential, the building has now a mixed use: offices on the ground floor and two flats for each of the four levels above and a maisonette apartment in the converted loft.
The most serious shortcomings of the existing building fabric included uninsulated walls, protruding balconies without thermal breaks and a lack of impact sound insulation in floors.
A survey revealed that windows alone were the cause of more that half of the heat loss transmission. The façade facing the road has been upgraded with a composite thermal insulation system with the result that the building still appears as part of the block development. The arrangement and size of apertures was not changed except for the larger openings on the ground floor.
The north façade and the roof were mainly made by timber elements, whereby the new, load-bearing façade has been set on new separate foundations.
On street facing façade (south), special attention was paid to thermal bridges: four of the eight balconies have been converted into alcoves and insulated without leaving any thermal bridges.
In addition to that, vacuum insulation panels have been added to the upper side of the balconies in order to avoid any possible step thermal between inside and outside.
The installation of a mechanical ventilation unit not only provides energy benefits but also blocks out traffic noise.
By moving the façade out on the courtyard side of the building, space was created to accommodate the service ducts. The technical concept also includes thermal solar collectors for the provision of hot water and space heating, as well as roof-integrated photovoltaic system.
The renewal of floors was taken as a chance to install underfloor heating system.
[project selected by Costanza La Greca]