In 1969 Miguel Fisac set out his ideas on the size and form of the city in a book titled ‘La molecula Urbana’, in which he expressed his reflections on urban planning after twenty years in the profession. In the same year, the magazine ‘Nueva Forma’ dedicated two issues solely to his work (Nºs 39 & 41), which included all his works up to that time, and with a critique by its director Juan Daniel Fullaondo, they make up a document that is fundamental to the understanding of the reach and the importance of the work of Fisac at the height of his career. It was also the moment when one of his other concerns started to manifest itself, that of the forms that enclose an architecture that was already determined by its use of reinforced concrete, but was still searching for its own nature, how could it attain a real expression of this material? In his roofs he was already achieving this using a functional and tectonic moulding of the concrete creating the ‘bones’ as an all-embracing solution in just one material to all of the constructive and expressive problems, but on the façades he still depended on wood, which along with plaster is the most versatile material, for the formwork. This is what he had been using up to that time for solid surfaces of varying degrees of elaboration. Wood gave rise to a grained texture, agreeably reminiscent of the warm tones of carpentry, but that did not stop it from being inappropriate as a resource.
This doubt led Fisac to try out a technique which would clearly show that concrete was a material that was poured in a liquid state, more closely approximating a stream of volcanic lava than a sedimentary fossil, and with his customary eagerness to put on his workboots, along with his assistants, he set to work improvising a mould made of wire and a fine sheet of flexible polythene, which would make evident the concrete’s genetic imprint as a soft, doughy material with no particular texture of its own. It was, perhaps, the last great discovery by this born inventor, and it became the identifying mark of all his works from that time onwards. The first example built, in 1970, was at the Clinica Mupag, a building with volumetrically complex façades, completely covered in concrete with a smooth, shining finish which still continues to surprise passers-by in that area of Madrid. His next project, in 1971, was the construction of his own studio –which he was moving from Calle Villanueva to beside his house at Cerro del Aire, and in which he used his various systems of posttensioned beams, and also the flexible formwork used to make walls ‘in situ’, rather than the prefabricated panels used in the Clinica Mupag. Fisac himself said that he used this work as a construction testing ground for other later works. The Tres Islas hotel on Fuerteventura (1973), a luxury house in La Moraleja (1973), or the building for the Editorial Dolar in Madrid (1974), in which the formwork is irregularly sectioned vertical bags, all display this smooth architecture in which even the cavities and ridges are rounded, giving the buildings a capsular, industrial appearance contrasting to the brutalist randomness of the epithelial texture.
Around this time the projects became less frequent, and the interesting project for the Centre for Hydrographic Studies of the Eastern Pyrenees, in 1977, never progressed beyond the drawing board, and although he constructed a large housing block in Daimiel using the same system of soft façades in vertical in 1978, he was forced to close his studio. The grand projects gave way to another type of works, like that of his own house in Almagro, which was a renovation of an old olive oil mill done with that special ability of his for integrating two very different expressive worlds in a totally natural way; the whitewashed syncretism of the small agricultural constructions of La Mancha, and the modern experience of flexible formwork. A different activity filled the extra leisure time that the architect suddenly had on his hands, the resumption of his artistic endeavours, now using techniques of soil and latex, more complex than sketching and watercolours. In the same city of Almagro he carried out an exemplary restoration of the tower of Santo Domingo in 1980, and in the same year he constructed a mausoleum in the cemetery at Burgos for Doctor Rodriguez de la Fuente. Three years later he constructed another church in Madrid, beside the parish complex of Nuestra Señora de Altamira, where he employed a completely different arrangement of religious space, the nave having a homogenous form with the zenithal light falling on the congregation rather than the altar. The architecture was more hybrid with a mixing of flexible formwork panels in a geometric pattern, with visible steel beams and concrete eaves. Whereas, in 1984, when he received the commission to re-construct the church of Pumarejo de Tera, in Zamora, he returned to the model used in the church in Vitoria, with lateral illumination directed at the altar, but using very simple uncut stone so that the villagers themselves could erect the building as a collective endeavour.