Schöck has supplied its Isokorb type KXT products for a Berlin-based contemporary inner-city housing complex called Paragon Apartments.

The project centres on the historic Prenzlauer Berg Hospital building, originally built as a school in 1912, but defunct in recent years as a hospital. Two new upper storeys have been added to the original building, three further existing buildings have been modified and there are two new structures. The ‘cube theme’ design framework comprises 217 high specification plus a kindergarten, a café and a supermarket.

All are formed as a three-dimensional façade involving terraces and a shifting stacked balcony pattern. The balconies, made of prefabricated concrete elements with glazed surfaces, are of varying depths, giving the apartments a spacious quality.

The Paragon building envelope and balcony construction is complex and it was important to address any possible thermal bridging problems. To meet the challenge, Schöck has supplied its Isokorb type KXT products, for concrete-to-concrete applications. With the balcony design, the plate and the canopy element for the balcony below act structurally on the same floor.

So it was necessary to connect the two free-cantilevered reinforced concrete plates using the appropriate Isokorb types in an alternating pattern.

The standard Schöck Isokorb type KXT element with straight shear and tension rods, was alternated with the Isokorb type KXT-HV. This has off-centre shear and tension rods on one side of the unit to enable connection to a downstand beam, where the balcony lies lower than the floor slab.

Both units meet the most demanding concrete-to-concrete specifications and transfer both negative moments and positive shear forces

In addition to the type KXT, the Isokorb types EXT and KS are also incorported. The EXT normally complements the type KXT in bearing high loads involving cantilevered external corner balconies, but on this occasion it is used to support the side wall loads.

The Paragon Apartments project provides an interesting example of how a variety of differing project specification challenges can be met, by designing-in a combination of Schöck Isokorb types.