Identification on the part of some members of RBTA with certain ideas of the Archigram movement, and enthusiasm for experimentation with geometry and its application possibilities to housing, are two factors that give tangible form to Kafka’s Castle, on a hill overlooking the bay of Sitges.

The concept of the castle –a spiral plug-in – is related interestingly to the Archigram School. The major similarities are the use of a separately expressed living and circulation structure. Here the capsule expresses new potentials, the only admission that these, of course, are not real capsules in the sense of being structurally self-sufficient, but could be built more easily.

This 90-apartment building is fruit of the clustering of cubes around nuclei of vertical circulation. Each staircase core is made of structural brick which extends to support half of each mother unit, the other half being supported on two steel columns, one on each corner. A two-way ceramic slab cantilevers in one, two, or three directions to form the floors of the plug-ins above, and the roof of the other plug-ins below.  The plug-ins are then built up in lightweight materials; road drainage pipes are used as window openings and simple wood carpentry is added. The whole is stuccoed and painted.

Each cube contains a minimalist environment: living-dining room or bathroom-bedroom, articulated on different levels. These “unités d’habitation”, despite their small size, are efficient and spacious, with flexible partitions inside, including shifting mirrors and open kitchen.

The color of the façades, chosen from a range of blues, expresses the intention to merge the building with its natural background, the sky.

A representational model was made of the solution and RBTA set about thinking how to solve the paper information so clearly that traditional presentation could be dispensed with. The fact that each stair core was fixed at more or less 0 m, that four units spiraled 360 degrees, and that each level changed 70 cms up the flight of stairs, produced all the relevant information necessary to build the project on one sheet of paper, with the aid of two secondary drawings clarifying the variations of the plug-ins, and so forth. Thus the project was built with the information deduced from the five sheets of paper. All detailing over and above the basics was determined directly on site.