Brief technical and architectural history

Carlos Machado e Moura
Pedro Borges Araújo 


Toute l’histoire de l’architecture tourne autour de la fenêtre pour donner de la lumière.
Le Corbusier / Pierre Jeanneret, Cinq points vers une nouvelle architecture (1926)


Windows constitute a more important element in modern architecture than they have in any architecture since that of the Gothic cathedrals. They are the most conspicuous features of modern exterior design. Their handling is therefore an aesthetic problem of the greatest importance. (…) Light simple frames, preferably of durable non-corroding metal in standardized units, are to be desired as much aesthetically as practically. (…) the general development in this direction is undeniable and one of happy augury for the contemporary style.
Henry-Russel Hitchcock / Philip Johnson, The International Style: Architecture since 1922, New York/London: W. W. Norton & Company, 1996, p. 61 (originally published 1932)


Here is the value of a wide sliding door opening pleasantly onto a garden. It cannot be measured by counting how often and how steadily the door is used or how many hours it stays open. The decisive thing may be a first deep breath of liberation when one is in the almost ritual act of opening it before breakfast or on the first warm and scented spring day. The memories of one’s youth and of the landscape in which it was spent seem composed, to a considerable degree, of this sort of vital recollection. There are in each life certain scattered quanta of experience that may have been of small number or dimension statistically but were so intense as to provide impacts, forever essential.
Richard Neutra, Survival Through Design, New York: Oxford University Press, 1954, p. 229.


Although their name refers to a formal achievement, minimalist doors and windows result mainly from a technical prowess. (1)1. For precision, it is necessary to clarify that the use of the term ‘minimalist’ is associated with the purity ethos of modern design and architecture, summarised in Mies van der Rohe’s ‘Less is More’.  It corresponds, therefore, to the reduction of each element to its minimum expression, eliminating redundancy through technical refinement. On the contrary, ‘Minimalism’ or ‘Minimal Art’ corresponds to an abstract artistic movement of the 1960s that promoted the reduction of the work to its essence, without any relationship to another reality. As the painter Frank Stella put it about his work, “What you see is what you see”. It is, therefore, an eminently conceptual achievement. It consists of the optimisation of a series of raw materials and manufacturing processes, which maximise glass surfaces and reduce the frames to the bare minimum.

The main innovation is that the glass, instead of simply filling the frame, becomes the structural element of the door or window, thereby becoming load-bearing. The frame – composed of aluminium profiles with thermal break section – is thus restricted to the function of sliding guide and ensuring the tightness of the window. This new expression for the frame enables the peripheral elements of the frame to be embedded into the floor, the ceiling and the walls, taking to the extreme the notion of transparency and immateriality that modern and contemporary architecture advocate and that was given great expression in the designs of Tadao Ando,​ John Pawson and Souto de Moura during the 1980s.

This text is composed of four chapters, which can be read sequentially or independently, and seek to revisit the technical and architectural history of this type of doors and windows. In the first part, we define what is meant by structural glass – a fundamental element of the minimalist window – and briefly describe the technical processes of its manufacture. In the second, much more extensive part, we give an historical overview of horizontal sliding doors and windows throughout the 20th century, identifying the main stages of their technological and architectural development from the Modern Movement to the present day. In the third, we trace the history of the minimalist window, through a brief journey through the projects and processes that have driven the wide variety of solutions currently available, tailored to the specific needs of customers. Finally, we point out the technical developments achieved in the 21st century and outline some perspectives for the future.