Deliveries to the site could only be made at the dead of night. This was only possible outside the hours the Düsseldorf streetcars run because the overhead power lines for the streetcars had to be taken down in some places to let the 15 m x 3.77 m prefabricated parts pass through the district of Benrath. The large turning clearance circle needed by the heavy haulage truck also required that bollards and sidewalk railings and guards had to be taken down and even that ramps and load-bearing covers had to be set-up for the sidewalks for the convoy to travel over.
The prefabricated construction was worthwhile despite all the extraordinary measures that were necessary. A surface finish of comparable smoothness and homogeneity would hardly have been possible from in-situ-placed concrete and it is these two properties that determine the character of the design in the long-term. These unusually large dimensions are because of the desire for a front to the building having as few joints as possible. In actual fact it proved possible to avoid any joints in the vertical visible to the eye by realizing these as mitre joints only in the corners of the building between the units. The windows have been constructed as storey-high units. These also separate individual units from one another. The lintel is set back in the form of a steel girder concealed in the plane of the timber window frame behind a panel of similar construction. In contrast to this, emphasis has been given to the two continuous horizontal joints by these being set back even further. The height of the floor of each storey can be seen here. The outside wall comprises a two-shell precast construction, the space in between the two halves has been filled with mineral wool. The surface of the inside wall is of fair-faced concrete quality as well, and is equally exposed. In the sequence of construction operations, the inside wall was first erected and a ring beam then placed to join with this. The prestressed concrete hollow filler block floor units for the second storey and for the roof were then placed on these. Since there is no basement to the extension, the base slab for the first floor was made by placing in-situ concrete together with the direct foundation.
The topmost prefabricated parts for the outside wall have a head that extends beyond the end of the inside shell. It was possible in this way to construct such a low and yet dependably sealed attic with only little effort required for the seal.
The building structure includes two vertical constructions. One is an open staircase made from steel in the interior; the other is an additional F90 stairwell, the steps for which are prefabricated parts as well. This stairwell to one side of the main entrance allows the option to rent out the two upper floors separately at a later point in time if so desired, though this is not the case at the moment as the owner intends to use the entire building himself. The space on the ground is occupied by the owner’s building contractor company. The company specializes in industrial sheds and these constructions preferentially use precast concrete units.
The simple cubic body exerts a certain formal reservation compared to the wealth of shapes and details of the original villa. The attempt has also been made here by the smooth concrete facades used in the extensions, to bring about a new interpretation for the homogeneity of the historical brick front from 1888 by applying modern construction techniques. And thus the extension can also be seen as being a continuation of the conceptual thoughts from 1888.
That this construction designed in line with classic Modern Age also meets the requirements of the construction principles of Feng- Shui from the Far East might at first seem a bit surprising since a principle of more unorthodox order would be presumed here for better harmonization with structures having a trace of anthroposophy. In fact this construction principle is based on a strict hierarchical arrangement of the individual functional areas of house. That in turn a strict and systematic order harmonizes with a rationally planned object, is, in contrast to this, comprehensible as well.
Interesting to know in this context is that the Chinese Kaiser passed a law regulating modular construction. This defines the permissible span widths according to the prosperity of the residents: A small pitch for poor people and a large span for the more wealthy. Against the background of this, the large span widths given by the precast parts can also be interpreted as congratulations from the architect hoping that the business activities of this property developer will continue to prosper.
Robert Mehl, Aachen