The notion of limit in architectural theory . Two case studies in Portugal

Modern Portuguese architecture has been seen as the result of an eminently empirical and intuitive practice, dissociated from any effort of theoretical structuring. This paper intends to contradict that predominant view, presenting the notion of spatial limit as a subject that earned particular consideration from a younger, more critical and intellectually demanding generation of architects. Firstly, it introduces two notions directly related to limit ‘extensions of the dwelling’ and ‘transition-space’ presented in theses by Nuno Portas (b. 1934) and Pedro Vieira de Almeida (1933-2011) respectively, two highly innovative works in the academic panorama of early 1960s. Next, it focuses on the fundamental role each of the notions taken in investigative works that are parallel in time but substantially different. The first, Habitação evolutiva, is a typological study reflecting the spirit of its time by claiming the ‘right to the city’ as the founding principle of a model critical of CIAM urbanism. The second is an essay stemming from a critical reflexion on the work of an eclectic architect that eludes categorization (Raul Lino, 1879-1974) which sheds light on the need for a critical approach to the history of modern architecture.

The rediscovery of spontaneous architecture, be it anonymous or without architects, 5 constituted a widespread reaction to the post-war crisis of modern architecture, attracting northern and southern European architects. The most influential publications of Italy, Spain, and Portugal, issued articles and, sometimes, [Fig.1]. Scheme by Alison and Peter Smithson on the streets of Bethnal Green: the street as social 'arena'. Source: Smithson, Alison, ed. 1967. Urban structuring. London-New York: Studio Vista-Reinhold Pub. Functionally, the 'transition-space' also constitutes a criticism of a stricter functionalism. Vieira de Almeida distinguishes it from other spatial elements by associating it with an ambiguity of action, that is, an unprescripted and open use that is not connected to the programme: 'Admitting the existence and need for nuclei, and therefore of action-defining areas, it is precisely where that action is undefined, unguided, that the feeling of ambiguity automatically appears'. 20 Although he defended a theoretical approach based on the generic characteristics of architectural space, Vieira de Almeida also admitted the usefulness of determining some spatial characteristics within a specific cultural context, namely, the  In that sense, the limit between inside and outside is presumed as provisory, 29 to be modelled by the inhabitants themselves according the family's growth and aspirations.
Typological definition considers not only the relation between built area and free area (essential to the evolution of the house), but also the relation between the lot area and the access areas, and rules for lot association, an instrumental aspect of the evolution of these ensembles to satisfactory levels of public equipment and free  of a limited group that shares a space that is adjacent to their houses [ Fig. 7]. In this case, they admitted that once 'certain stages of adaptation were surpassed', the free spaces initially allocated for neighbour communities would be occupied by facilities of interest for the urban community, 'contributing for the integration of neighbour nucleus within the ensemble of the city'. 33 By considering that the urban fabric to be created in a relocation should establish relations of continuity to its surroundings and foresee facilities in a broader network of services, Portas and Silva Dias alluded to the creation of wider spaces of conviviality, associated with favoured social classes and more urban behaviours of use of the city as a whole. 34 Although the study of evolutive housing is part of a broader picture of critical studies within modern architecture and CIAM urbanism and is a reflection of a paradigm shift in housing that marked the 1960s, 35 it is also the product of a specific cultural reality. In fact, the document established a determined type of social organization that was connected to Mediterranean culture. The authors made this very clear by stating that the solutions presented tended 'to compact ensembles around concentrated public spaces, closer to the tradition of a "system of streets" than to "dispersive free space between building blocks"'. 36 By recovering this model, The 'transition-space', a key to interpreting the work of Raul Lino  Vieira de Almeida assigns to these two elements -atriums and porches -a fundamental role for a feeling of 'welcoming' and 'shelter', values which he highlights in the work of Raul Lino and which relate directly to the notion of limit.
However, this limit is not defined as an unequivocal confrontation between two opposing realities (a hostile outside and an inside that greets and protects, in the [ Fig.9]. Raul Lino: Monsalvat House, 1901. Source: França, José-Augusto;Pimentel, Diogo Lino;Rio-Carvalho, Manuel, coord. 1970 thickness and of column profiles completely changed the notion of limit between inside and outside. The revaluation of 'transition spaces' in the work of Raul Lino enhanced the timeless qualities of an architecture that assimilated from popular tradition the distinct gradations and shades of light and temperature introduced between the interior and the exterior through the creation of semi-open living spaces with no functional separation.
Pedro Vieira de Almeida acknowledged that, in the work of Raul Lino, the expressive strength of syntax had obfuscated latent semantic concerns. Concerns that were set on ecological bases not so much on the terms of adaption of houses to the climate as on the way of life they fostered: to inhabit the diffuse limit between inside and outside, architecture and nature, shelter and adventure.

Conclusion
The in this research process, which opened the way for Portas' interest in urbanism.
As for Pedro Vieira de Almeida, the 'transition-space' is a part of the conceptual tools he used in his critical analysis of 20 th -century architecture. In the essay on Raul Lino, it is the key to assigning a whole new meaning to his disparate work.
This was the first in a series of critical essays on relevant Portuguese architects of the 20 th century (Carlos Ramos and Viana de Lima would be studied respectively in 1986 and 1991, also within the context of monographic exhibitions) in which Vieira