Link between old and new with elegant floors made of Dyckerhoff TERRAPLAN

The parliament of Lower Saxony has its domicile in the castle Leineschloss in Hanover, a classicistic palace complex in which the kings of Hanover resided until 1866. When it was rebuilt after the Second World War in 1962, it was extended to include an annex for a plenary hall designed by the architect Dieter Oesterlen. A modernisation and extension of the listed annex was urgently needed. However, the client, the State of Lower Saxony, wanted to deal with what had already been there with dignity.

The Stuttgart architectural office blocher partners succeeded in the balancing act between old and new, contemporary transparency and sophisticated spatial planning, monument and copyright protection as well as professional renovation. The former inner courtyard is now the foyer which is open to the public. The generous 400 m² glass roof of the new Portikus Hall, which provides natural lighting, the surrounding white columns and the likewise white, elegantly shiny floor give the newly created interior an impressive yet functional appearance. The historic Lower Saxony staircase (Niedersachsentreppe), also in a bright design, is now in direct view. After a good three years of construction, the building has been available to the state parliament again as a conference venue since autumn 2017.

The floors of the Portikus Hall and all other public areas are made of Dyckerhoff TERRAPLAN. In total, the company R. Bayer Betonsteinwerk from Blaubeuren laid 3,500 m² of the polished concrete floor system with a terrazzo look, manufactured on the basis of Dyckerhoff WEISS. The light appearance was also achieved by using pearl white aggregate (maximum grain size 8 mm). The installation height is 8 cm plus insulation or underfloor heating (on 50 % of the surface). In order to enable blind and visually impaired people to move around the building without danger, the walkways were implemented with a tactile floor guidance system in brass. In contrast to the noble, white TERRAPLAN floors, the floor of the cafeteria has a functional modern appearance. The basis for this concrete floor, which is also polished, is white cement. The addition of concrete gravel created the granular structure. 

When the jury decided in 2019 on the awarding of the BDA Prize of the Lower Saxony Federal Association of the Association of German Architects, it judged the conversion of the Lower Saxony State Parliament as an exemplary architectural achievement. It is a "successful example of the comprehensive adaptation of a historically significant and listed ensemble to the changed requirements in function, aesthetics, atmosphere and comfort of today". This is the second time that the building in Hanover has received the coveted prize, as the original building was also awarded this distinction in 1976.

(Photos 1,2 and 10: Joachim Grothus for the architectural office blocher partners)