High density, low energy project in Vienna demands proven performance values

This is certainly reflected in their approach to a high density project in Tokyo Street, Vienna; which has been nominated for the European Prize for Contemporary Architecture – Mies van der Rohe Award, 2011.

The original concept was for terraced housing, but to optimise space utilisation it was decided to stack different types of housing on top of each other. There is an elevated tract of 'Casablanca' apartments (single-storey apartments with a two-storey high loggia space) placed along the length of the Tokyo Street construction block.  All units are the same size, made possible by rotating the living room 45° and adding triangular loggias with a balcony docked on. The balustrades, alternatively set back and protruding, are made from expanded metal linked by trellises and have already been christened 'spiders' by the neighbours.

On the courtyard side, single-roomed apartments form the counterpart to the street arcade and on top of these units, there are maisonettes arranged in an L-shape around a two-storey atrium with an earth box and a covered patio. The third layer is made up of a row of two-storey terraced homes with gardens and a children's play area in the middle. At the very top, the typical and very popular, Viennese small garden house has been incorporated into a tight structure, lit from the south and narrowing conically towards the courtyard.  The develoment is formally known as the "The Town Musicians of Bremen" – a reference to a folk story by the Brothers Grimm, where at one point a donkey, dog, cat and cockerel stand on each others backs to gain height.

Designer Richard Manahl explains: "Our aim was to achieve as differentiated a range of spaces as possible, with all of the 100 apartments having plenty of exterior space and daylight from at least two sides.  Thanks to the complex cofiguration of the construction resulting from the stacking concept, there is an extremely large surface area compared to an ordinary apartment block.  However, it remains a low-energy house".

Legislation, along with the need for energy conservation and a reduction in CO2 emissions, demand that preventing thermal bridging is now a critical consideration in the construction process.  In a building as complex as this, thermal partitioning at the cross-over points – for example the access balconies – is a crucial element if condensation and mould growth are to be avoided. One of the most effective solutions is the Isokorb® range of thermal break modules from Schöck, which offers outstanding thermal insulation properties and dramatically reduces thermal energy loss in connective areas, by guaranteeing the homogeneity of the thermal envelope between cantilever structures and the internal floor.

The Isokorb® also transfers load and maintains full structural integrity, while at the same time enabling inner surface area temperatures to remain well in excess of those likely to cause mould formation and condensation.  The products in the Schöck range are unique on two counts. They are the only thermal break solutions to allow connections to be made between concrete-to-concrete, concrete-to-steel and steel-to-steel – and also provide BBA Certification and LABC Registration.

In total, 720 Isokorb® units are incorporated into the Tokyo Street project and Anton Harrer, the geotechnical engineer responsible comments: "We always recommend installation of the Schöck Isokorb® because we know it has proven performance values, also the contractors wanted to use Schöck components as well".

In addition to the Isokorb® units, 134 Schöck Tronsole® units have also been used in the staircase construction as soundproofing.  Today, good sound proofing is an increasingly important characteristic, particularly in the stairwells of apartment buildings.  The Schöck Tronsole® is a complete, dependable, ready to build impact sound insulation system that is quick and cost-effective to install and meets compliance with the necessary building stairway regulations.  All the stair connections and joints are completely sealed for cleanliness, avoiding any possible sonic bridges being formed by stones or brick chips becoming lodged.

Architect:

ARTEC Architekten, Vienna, Bettina Götz and Richard Manahl
www.artec-architekten.at

Project leader:

Michael Ivancsics

Support structure planning:

D. I. Anton Harrer, Krems

Building Physics:

Ing Rainer Stepan, Wien

Developers:

New Life, Non-construction, residential and municipal cooperative Reg.Gen. mbH