An old watchmaker’s mansion, built in 1915, is the core of the new KSTA residence. The first step to fulfil the new needs was to liberate the mansion from the previous additions back to a single cube of 9 by 9 meters. Then a prefabricated two storey wooden annex was added on the West side, facing the lake, and a two storey wooden addition on top of the building. The new villa is three times as big as its original and turns to a landmark. The interior transformation plays with the keynote of the original substance of the old house and interferes gently with the predominant atmosphere of its core. The original substance dictates the new space organization, which leads from the core to the prefabricated additions and reaches out to the subtly defined exteriors. The rooftop terrace offers a new breathtaking view of Lake Zurich and the Alps.