The residential area on Tischendorfer Strasse in downtown Plauen was not one of the most popular in the past: prefabricated buildings dominated the scene; they were the last of their kind to be built in the city on the edge of the Vogtland region during the German Democratic Republic (GDR) era . The apartments were no longer in demand by tenants, even though living space in this central location of Plauen is actually in high demand. The Plauen housing association was faced with a decision: Demolish or renovate? It decided to preserve the old prefabricated buildings and began a comprehensive renovation, including the addition of two floors.

This had two positive effects. Additional living space was created in a desirable downtown location without having to seal off new areas. And the cityscape also benefits: The monotonous appearance of the prefabricated building was enhanced by the increase in height, and the redesigned block now blends harmoniously into its architectural surroundings. The tenants like it; suddenly there is a renewed interest and demand for living in a prefabricated building.

Larger apartments and additional floors

Before the construction, the complex consisted of one-, two- and three-bedroom apartments with kitchens and bathrooms, no balconies and no elevators. This no longer met the needs of today's tenants. Therefore, the floor plans of the former 76 apartments were fundamentally changed, and the units were gutted. The result was 36 more spacious apartments with bright bathrooms and kitchens, balconies and an elevator. The apartments are now barrier-free and wheelchair accessible. The loss of living space was at least partially offset by the addition of two floors. These two new floors now form the heart of the complex: they have been equipped with particularly large living rooms and roof terraces, from where the view over Plauen towards the Vogtland region is impressive.

Adding floors with autoclaved aerated concrete offers advantages

The addition was made possible by the use of Ytong autoclaved aerated concrete (AAC), which proved to be the optimal building material for the project. Initially, the client had planned to build a timber extension. However, this would have required a complete overhaul of the building's fire protection. AAC, on the other hand, is a mineral building material that is non-combustible and inherently fire-resistant. The requirements of fire protection class F90 were therefore immediately met.

In addition to the good fire protection properties, there are other advantages. Ytong AAC is lightweight. For an extension like the one in Plauen, the existing foundations did not need to be reinforced. That saves time and money. In addition, the solid building material has thermal insulation properties. Even without additional measures, the building meets the energetic specifications. The climate in the rooms is perceived as pleasant by the occupants because the cellular concrete compensates for temperature fluctuations. This is an advantage for the two new upper floors, especially on hot days.

New partition walls made of Silka calcium-silicate blocks

Ytong AAC was used for all the new floors, as well as for the intermediate ceilings, floor slabs and roof slabs. Another material, Silka calcium-silicate blocks, was used for the apartment partition walls, the walls facing the staircase, and the walls of the new elevator shafts. Both materials complement each other as they are both based on natural and mineral materials such as sand, lime and water. The structural design of the floor and roof slabs for the entire elevation project was carried out by Xella.