Description

As part of a joint initiative to investigate construction methods with greater potential for prefabrication than the usual parallel wall and concrete slab method, the two Viennese architectural offices ARTEC and Wimmer und Partner came up with the idea of leveraging the construction system used for multi-storey car parks as a basis for housing. The multi-storey open structures offer a high degree of flexibility that in conjunction with modular insertions offers potential for housing, especially in the context of the current trend towards small apartments. Should this trend change in future, the system is flexible enough to allow apartments to be joined together at a later date. In Vienna, for example, there has been a rise in so-called Smart Dwellings that have three rooms and a floor area of no more than 65 m².

Together with Klaus Bollinger structural engineers in Frankfurt, the two offices developed their idea and produced a joint design for a building system based on the multi-storey car park system by Peikko. The parking decks are 16 metres wide: two strips of 5-metre-deep parking bays with a 6-metre driveway between them. The schematic section shows clearly how the architects have adapted this principle to meet the needs of housing. The base of each unit is a layer of hollow-core slabs resting on the steel beams of the structure with prefabricated ventilated timber-panel elements placed behind the reinforced concrete columns of the structure. The sanitary areas have prefabricated timber panel cores with thermally isolated ceilings and floors. The depth of each thermal unit is 10.6 metres and the open cantilevered slabs on each side act as a fire barrier between the floors, making it possible to use timber facades: as lightweight non-loadbearing elements, they contribute to minimising the structural dimensions of the construction and together with the steel structure and lightweight hollow-core elements enable a smaller column-grid and wider spans. For the apartments, the simple garage construction has some noteworthy spatial advantages: In the pilot project in St. Pölten, an almost luxuriously deep 2.8-metre strip was created on either side for outdoor use, as a balcony on one side and as access gallery on the other. This effective construction system can also be adapted to meet local building regulations.

The two offices proposed this system for three separate property developer competitions without success before being awarded a direct commission in St. Pölten together with the BWS (Gemeinnützige Allgemeine Bau-, Wohn- und Siedlungsgesellschaft) from Vienna, which was courageous enough, along with the project developer Robert Korab, to realise this pilot project.

On a rectangular site with a protruding section off to one side at its north end, four north-south oriented housing blocks with a length of 75 metres and a width of 16.2 metres were erected from 2015 to 2017, supplemented by a half row at the north-west corner. This special block features a roof terrace open to all residents. The four housing blocks are connected to this terrace by bridges at the same height. The two buildings to the east, on Praterstrasse, have four decks of housing while those on the west have one storey less. The top decks have two-storey apartments with gable roofs. The two blocks facing the street were designed by Wimmer und Partner, those to the east by ARTEC.

Originally published in Bauwelt 28-29.2016, pp. 30-33, abridged and edited for Building Types online, translated by Julian Reisenberger

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