Eight-storey record

As cities continue to grow, the demand for high-quality and affordable housing in dense urban environments increases. Vienna is no exception. In fact, the biggest city in Austria is in dire need of affordable housing. In Vienna’s 12th district, a residential area of almost 11 hectares was completed in 2024. Called the Wildgarten, the land is filled with buildings and projects of all scales: from two-family homes to multi-storey apartment buildings. Today, 2,300 people inhabit the 1,100 housing units.
 
Marking the end of the multi-stage construction phase, the last 14 residential buildings were erected between 2023 and 2024 and all 14 of them were planned in monolithic clay block construction. Two of these buildings are eight storeys high, setting a record – the world’s first high-rise monolithic clay block building with integrated thermal insulation, where the entire load-bearing structure is made of ceramic masonry.

For these 14 buildings, a total of over 205,000 clay blocks were used. The architect’s aim was to treat the material with the utmost respect: architects and developers designed the buildings in a way to minimize cutting. “In the vertical direction, the distance between the top and bottom edges of the raw ceiling is 2.77 m for all houses – this corresponds exactly to 11 blocks heights”, says Gerd Pichler, Head of ARE Project Development. The two eight-storey residential buildings in Wildgarten impressively demonstrate how versatile and efficient clay blocks are, even at lofty heights. Apart from its innovative aspects, Porotherm W.i creates the pleasant indoor climate of familiar clay block walls, reduces energy consumption, and contributes to a healthy living environment.
 
The two eight-storey residential buildings prove that clay blocks are a robust material that meets modern demands and is convincingly practical in constructing the sophisticated high-rise buildings of our time. To check the load-bearing structure in advance, a special software was developed: Based on a program for calculating reinforced concrete and timber structures, it was adapted to perform complex calculations for ceramic masonry.

“An acoustic screen of 45 m height and 22 m length has – to our knowledge – never been realised before. Two large concrete columns were fixed to the buildings with a steel structure. One building serves as a fixed point, and the other as a hinged point to accommodate the movement between the two buildings,” says Bert Lenaerts, CEO of Groep Vanhout.
 
A special challenge lay in completing the façades, exterior finishes, and the screen simultaneously on a limited work surface. “Building this unique design presented some complex technical challenges, culminating in the acoustic glass screen. Thanks to our engineering and good coordination with all parties involved, we certainly succeeded.” Surrounding both towers is an undulating, atmospheric park garden with low planting and multi-stemmed trees, designed by landscape architect Dirk Vandekerckhove.