From a designer’s point of view, the architectural design of the building was defined by three criteria. The first one follows from the history of the house. Only few valuable elements of architecture history remained intact in the house, which had been completely rebuilt and reorganised over time. These values are manifested with different tones in the two masses of the building. The other major aspect is the diversity and plasticity of the move-in function, which mainly defined the system of interior spaces. The third feature is the extensive system of walkways located under the building.  The building includes a cellar and walkway system of ~1850 m2, with two main levels. A tortuous corridor and hall system at the level of Lovas street and a 40-meter-long, 8-meter-wide and 9-meter-high space, which includes three floors with two dividing ceilings, at a depth of -30 m below the ground level of the building.
Extensive research was carried out into how this underground world could be integrated in the life of the building, and at last only conservation was performed in the cellar spaces, and the world below only appeared indicatively in the house. Thus, the other two architectural organiser principles were given greater emphasis, with the underground corridor system being indicated by the staircase leading from the reception area.
A major challenge in organising these functions was the fact that, despite the small scale of the building, the client had visioned a wide range of usage. In addition to the undisturbed research work, space had to be allocated to informal meetings, seminars, private negotiations and inspiring collaborations. During the design contest phase and the finalisation of the conceptual design, various environmental psychological methods were used to assess [1,2] the expected use. We tried to strengthen, emphasise and integrate initial client goals with spatial management into the future life of the building. The goal was to create a stimulating work environment that inspires users of the building with the possibility of accidental encounters and diverse usage through a mix of functions and the meeting of users with different motivations (guests, visitors, researchers).
These assessments influenced the design indirectly, rather than directly, serving as inspiration, and mainly forming the building's internal organisation. The architectural intention was to establish a space that can be “circumwalked” at all levels, and to avoid the creation of dead end situations. The vertical circulating areas located at three different points, the two staircases and the elevator provide flexibility and thus bring the courtyard with the glass roof into focus. This circulating system with two stairways and circular corridors was already in place in the late Baroque period, but was completely terminated during the transformations and from then on, the two building wings were operated as separate units, without direct access. Coverage of the court on the ground floor allows the free use of the court. On the first floor, a new architectural element, a bridge connects the two wings of the building. In the attic area, the original roof shape would not allow the two building wings to be connected, so the glass roof layout was removed from the contour of the inner court and raised to create a cloister around the court. These circular corridors at each level are joined vertically by two stairways of different characters.
Besides the usage of the house, the other fundamental organising principle was the architectural treatment of the historic elements of the building. The renewed exterior appearance of the house was determined by the double character that accompanied the history of the building. The wing on Úri street is the oldest part of the building, and several credible photographs and surveys of its original Baroque facade are available. We therefore decided to carry out an authentic recovery here, reconstructing the original mouldings and restoring the late Baroque facade. After the removal of the outer facade plaster, the recognition of the visible wall structure confirmed our suspicion that the opening elements had originally been framed by stone in this part of the building. We restored the original stone frames for these windows and opened the wings in and out, in line with the original Baroque design.
The wing overlooking Tóth Arpád promenade was given a more puritan architectural appearance since the birth of the building. This part was completely retailored between the two world wars, with the addition of new elements. In the post-war recovery process, the building part was once again given a completely new opening system, but some elements were kept from the previous conversion. Such are the corner balcony and the roof extension. In this part of the building, we found another doorway on the archive maps, which led us to plan a new opening to Kapisztrán square. There remained no credible photographs of this wing of the building, so we decided here to keep the impressions of the various eras. These historic elements were complemented by contemporary architectural elements: the bridge between the building parts, the glass roof and unique metal shutters on the facade. The exterior appearance of the building is dominated by this duality, that is the historical restoration of the Baroque age and the existing facades enriched with modern elements.
The construction of the building required continuous site inspection, as the monument building provided numerous new surprises, despite thorough excavation and preparation work. In addition to the technical issues, there were three professional areas which, in their appearance, essentially defined the architectural character of the building. The design inspection of these components had a fundamental influence on the final design.
In case of the glass roof covering the court, the primary goal was to make the structural steelwork as lean as possible. The roof geometry is a parametric leaf surface made up of triangles, composed mainly of fixed-glazed triangular fields and RWA windows opening at the indicated locations. Due to the membrane structure, the height of the “V” girders of the rib structure is 22 cm. The glazing was made 15 cm apart from the support structure, forming a separate surface. The geometry of the glass roof was determined by the building's features. The lowest ridge on the Kapisztrán square side marked the lower plane of the roof, and the height was determined by the view from the square. The shape superimposed on the court with the irregular floor plan was inserted between the two elevation points.
In the interior of the building, the unique terrazzo covering represents the more marked architectural intervention points, adding a consistent character to the building. Previously and locally made terrazzo was also built in within the building. The large grains were mixed with a medium-to-dark grey marble and yellow marble, and for the base mixture, limestone from the Pilis mountains was used. In the attic, for the spandrel around the courtyard, yellow marble was combined with the base mixture of white-cement Carrara marble. At the two stairways and the bridge, we encountered various challenges with the use of terrazzo. The difficulty in the main stairway was to coordinate the reinforced concrete stair structure, the steel balustrade structure, the pre-fabricated terrazzo and the plasterboard installations. The balustrade of the staircase on the stairwell side was fitted with terrazzo finishing from inside, the support structure of which was fixed to the reinforced concrete structure of the staircase. The different inclination angles resulting from different arm widths were brought into line by the suspended ceiling planes below the stairs. Due to the geometrical complexity of the smaller curved stairs, both vertical and horizontal terrazzo surfaces were made on the site. The large grains had to be evenly mixed on the site into the vertical panels and the curved recessed skirting in such a way that they are compatible with the grain distribution of the horizontal surfaces.
In the steel bridge, the movements caused major challenges. The bridge structure had to be assembled from three parts. Due to structural bouts and movements, a synthetic resin-based terrazzo was created here.
The two key architectural structures, i.e. the metal structures and the terrazzo finish meet the most strongly at the bridge. In addition to handling movements, the floor covering also required paying attention to the fixing of the bridge railing. The rod railing elements were placed in the receiver sleeves located on the bridge support, and the bronze collars are in the plane of the terrazzo finish at the reception part. The bronze railing on the bridge reappears at several points in the building. At the cellar entrance, the rod solution appears, while the steps were also equipped with railing made of bronze.
Besides the railings and the bridge, the other articulated metalwork elements are the new steel gate and the top-floor steel shutters. The metal surfaces on the outer facade were perforated individually. The concept of motorised movement of the shutters was discarded during the construction phase, and therefore a unique mechanical opening and locking method had to be developed.