Renovation of the Old Royal Palace and the exhibition The Story of Prague Castle

The subject of the project was the modification of the Old Royal Palace (SKP) at Prague Castle in connection with the preparation for the installation of the long-term exhibition "The Story of Prague Castle." Given the exceptional significance of the complex, the modifications described below are not a reconstruction - there was virtually no intervention in the original construction substance and the restoration of the palace's interior (flooring, plaster, stone elements, windows, and doors) was carried out by the same contractor in parallel with the construction modifications - but rather an addition of new elements necessary for the operation of the new exhibition. However, the construction interventions are intended to be a permanent adjustment regardless of the (non)existence of "The Story of Prague Castle."

Concept and Materialization
The proposed modifications can be characterized as insertions. In the structural sense, this means removable placement on existing structures. Similarly in the architectural sense: by choosing such materialization and shape of complemented elements, which consciously refer to modern origins, it does not overshadow the quality of preserved spaces and also allows these interventions to be "read" and separated from the structures that have lasted for centuries. Steel was chosen as the basic construction material for the newly inserted elements (floors, staircases, leveling ramps, infill panels). Steel is presented in visible parts of the structures in two forms:
all horizontal, i.e., walkable structures (walking layers of floors, leveling ramps, staircase treads) are designed from stainless perforated sheet metal (expanded metal) with a surface treatment of staining and shot blasting. In contrast, vertical structures are made from smooth steel sheet with a surface treatment of gray-black metallic paint.
Where the operation of the exhibition requires it (infill panels, railings), steel is then combined with clear safety glass.

Newly Inserted Horizontal Structures in the Interior of SKP
The most visible intervention in the interior of the palace aimed not only to make some spaces accessible and connect them but also to maximize the possible exhibition areas and protect the spaces located under the structures (e.g., archaeological terrains).
The load-bearing steel structures are placed on foundation strips or directly on historical structures through separating layers - they are therefore not anchored to the historical constructions. Given the uniqueness of the interior spaces of SKP, it was not permitted to join structures on-site by welding. The load-bearing structure composed of hot-dip galvanized closed profiles was therefore divided into individual parts and equipped with bolted connections (the size of the individual parts was limited by the size of door openings on transport routes and the weight of the elements, which had to be transported manually). All new floors consist of a walking layer made of stainless expanded metal with a thickness of 3 mm. The floors also include two glazed openings in the Duke's chamber and fully glazed railings allowing a view of the Romanesque wall or the earthen structure.

Staircases
Due to the needs of the exhibition, the historicizing staircases made of solid wood from the second half of the 20th century were replaced by steel staircases (with tread expanded metal and smooth sheet railings; without risers) of a more delicate shaping that corresponds to the overall spirit of all inserted elements. The only staircase without a "predecessor" is the connection between the Duke's chamber and the Theresian wing. These doubled "trouser" straight stairs are inserted into the neck next to the spiral staircase designed by architect O. Rothmayer.
The main load-bearing element of the staircases is generally a solid railing made of a strong plate and a truss structure from closed profiles. The entire railing is covered with thin sheets.