« How do we pile up dwellings without sacrificing their independence ? » Nicolas John Habraken asks the question in those terms in the book he first published in Dutch in 1961 then in English in 1972, Supports: An Alternative to Mass Housing, as an introduction to the research work he led during a long part of his career. The theory of supports, which framed the work of the SAR (Stichting Architecten Research, the Dutch foundation for the architectural research) headed by Habraken since its creation in 1965, establishes the basis of an architecture for which the progress in the industrial construction area enables a high urban density while it allows its inhabitants a personal recognition of the needs and necessity at the domestic scale. If this questioning was expressed in reaction to the massive construction projects of the 50¿s and 60¿s in Europe, it still remains unanswered nowadays. Through the concept of this support architecture, the research work of Protostructure, archéologie et hypothèse d¿une architecture-support tends to take a contemporary glance at the problematic stated by Habraken. The term of support hold in French a double meaning: physically supporting someone or something, and simultaneously, to bring a moral support, with forgiving and benevolent values. The idea of support architecture relies on this double definition designating both the object and the action of supporting individuality of users, adapting to their own practices of living. The transposition of this notion of support architecture to density and urban diversity bring forth in the research to the use of hybrid objects, able to answer systematically both at the collective scale and at the level of the user as an individual. The concept of protostructure tends to define this peculiar duality that. Neologism formed by the prefix proto-, which means first, and the substantive structure, from the Latin verb struere, constructing, it designates a structure or a system at a primary state, devoid of the artefact it supports. Protostructure applied to the architectural project proceed as a rule of the game: it creates the general basis of a process of individual appropriation. Protostructure is the starting point and the guideline of this research. The definition of this transverse notion allows in a first part to elaborate a case study which has the particularity to implement a collective support dedicated to the active participation of its inhabitants individually. The analysis of those cases, collected inductively by analogy to the conception of support architecture, establishes the first part of this work under the form of Archaeology. The second part of this research, comes back in the form of a Hypothesis. It has been experimented with a collaborative construction in the frame of the teaching of the first year design studio at EPFL. The story of this work, singular in many ways, provided an fruitful insight on the primary definition of protostructure. Through this twofold inquiry, the research Protostructure, archéologie et hypothèse d¿une architecture-support enunciates a critical and efficient analysis of architectural conception processes concerted between architects and inhabitants, offering new perspectives on the architecture project practice.