The Sphere next to the main house represents an entirely different concept of living. A micro house contained within a 5m diameter concrete shell.
To create the sphere the Perugini used the same method they tested for the creation of the bathroom shells. The shape of the half-sphere was hollowed out in the sand next to the site. A wooden scribe was used to even the sides and using a plaster the shape was defined.
Then using a second scribe slightly smaller the concrete was spread evenly around the mould. A mesh reinforcement embedded in the cast.
The centre of the scribe can still be seen in the azimuth of the spehere.
After completion, the whole shell was extracted with a pulley system and placed on site.
The second half was then cast into the mould. This second half-shell was mounted on top of a separating ring structure onto the first shell. This ring now contains a perspex transparent strip.
Sketch by Perugini showing how the half spheres were cast into the ground.
The first bottom shell after it has been extracted from the mould. The wooden support stabilised the fragile concrete shell during the extraction and mounting process.
The top shell placed on the bottom half shell.
This drawing shows how the Peruginis planned to fit out the sphere. A suspended globe contained the bathroom and the bottom globe could be unfolded to form the bed.
(Al images copyright by the Perugini family archive. )
In hos book Casa Albero, Giuseppe Perugini writes this about the construction and the functions of the Sphere:
THE CONSTRUCTION OF THE BALL AND THE SERVICES
The inspiring principle of their construction is the system of potters. In fact, the first step is to carry out an excavation aimed at obtaining the space to make the initial mind the guiding form, which is also facilitated here by the sandy soil. A vertical pole is then fixed in the center with a welded iron sheet suitably shaped so that, by rotation, the desired shape can be obtained. After a first rotation of the shaped rod, which regulates the excavation, always rotating, plaster is thrown which, depositing itself on the walls, thickens and creates the real counter form. Then we proceed with the installation of a steel reinforcement made separately and fix a galvanized iron circle on the upper part of the resulting form. At this point the initial foil is replaced with one of reduced dimensions, determined by the thickness that is intended to be given to the element to be made and then the concrete is cast by still rotating the rod on itself until the cement has purchased a certain consistency. After the time necessary for the setting of the cement, it is necessary to dig around the counter form that is pining, thus releasing a perfectly finished object which is then removed with the crane and moved for laying. It is a substantially very simple system which, as in this case and if the conditions exist, it can also be carried out on site. The two half-caps that make up the Ball were also made in the same way but with further precautions. In fact, after having made the two parts that they constitute it, a particular COSTITU support structure was made up of a series of “U” beams – suitably pie gates – and large C in galvanized metal, while, as we have said, the choice to tilt the glass junction point made it possible to avoid a sense of static nature that a horizontal solution would have generated. The structure of the house and the ball under construction Scheme of the construction technique of the services and the ball.
Given the purposes that these short notes propose and the small space available, I think I will not have to go any further by recalling here the purposes and the “old-fashioned” method of the treaties whose purpose was to allow the dissemination of ideas, elements and their explanation. I understand perfectly well that Casa Albero can appear at first sight as an object in its own way eccentric, like the dream of a visionary architect, but I hope that whoever reads these lines will recognize its true meaning, its true role, which it is that of “mo of the experimental”, finding in the compositional choices made the concretization of all those values, even symbolic or unconscious, which have always been part of the very idea of Architecture.”
Giuseppe Perugini, Casa Albero