Schöck performance for world’s largest passivhaus scheme

The historic city of Heidelberg, in south-west Germany, is residentially very popular, with barely any property available in the city’s picturesque old town and little room for expansion.

The spectacular solution is to build a completely new district – the Bahnstadt – on a 286 acre area that was once Heidelberg’s rail freight and marshalling yards. The €2 billion initiative is claimed to be the largest single passivhaus development in the world and by 2022 will provide living space for around 5000 residents. All buildings, not just residential properties, will meet advanced passivhaus standards.

Balconies are an important feature in Bahnstadt, but with high insulation levels and the prevention of thermal bridging being critical in passivhaus design, balconies have not been a popular choice with designers. The Schöck Isokorb type XT structural thermal break unit has changed that perception. This latest generation product for concrete-to-concrete applications offers such a high level of insulation that the Passivhaus Institute in Darmstadt has awarded it with the “low thermal bridge construction” certificate and confirmed its suitability for passivhaus construction.

Thousands of type XT units are incorporated into the Bahnstadt development and the major reason for its suitability is the thickness of the insulation body. Now increased from the standard 80mm to 120mm, the thermal insulation performance is up by 30% when compared with the standard range and impact sound insulation is increased by around 50% as well.

The type XT offers architects and engineers a variety of design options, including the capability to construct stepped height balconies, with increased fire protection also taken into account. High quality stainless steel bars are an integral part of the unit and although the rod diameter is smaller, the tensile strength is improved and the same load-bearing capacity maintained. This means a reduction in the thermally conducting cross-section.

The Schöck Isokorb range allows connections to be made between concrete-to-concrete, concrete-to-steel and steel-to-steel – and in the UK, all units meet full compliance with all relevant building regulations, while also providing BBA Certification and LABC Registration.

For your free copy of the Schöck Specifiers Guide and / or the Technical Guide contact the company on 01865 290 890 or visit