Joelho - Journal of Architectural Culture

The Ground Floor as Navigability Interface: Path Availability and the Architecture of Urban Thresholds

Gonçalo Melo

Architectural criticism possesses rich qualitative vocabularies for the ground floor—threshold, interface, in-between space, urban edge—yet no formal framework for evaluating whether a ground floor measurably expands or restricts the range of paths available to those who traverse it. This article proposes one. Drawing on space syntax (Hillier, 1996), ecological perception theory (Gibson, 1979), and information-theoretic principles (Shannon, 1948), it introduces a navigability framework in which the ground floor is understood as the architectural element where the structural availability of urban paths is most critically determined.

The article advances two formal distinctions. The first concerns the differentiation capacity a ground floor affords its users: the number of distinct continuation options perceptible at the threshold—entrances, passages, shopfronts, arcades, terraces, stairways, ramps—constituting what this framework terms Perception. The second concerns the structural resistance the ground floor imposes on traversal: setback, opacity, gradient, programmatic homogeneity, access control, and the conversion of collective ground into private enclosure—constituting what the framework terms Distortion. The ratio between differentiation and resistance defines a ground floor's navigability: the higher the perceptible alternatives relative to the encountered resistance, the freer the threshold.

This framework reinterprets the ground floor's historical and political significance. When the call for papers notes that economic crises, functional changes, and security lockdowns are felt first at the ground floor, it identifies a pattern the navigability framework formalises: each such mutation reduces differentiation (fewer active frontages, fewer programmatic alternatives) or increases resistance (gates, blank walls, privatised passages), compressing the navigability of the threshold. Conversely, the agora, the arcade, the bustling café terrace, and the porous colonnade are architectural configurations that maximise available paths at minimum resistance.

The argument is developed through three Portuguese case studies analysed at the scale of the ground floor. First, the medieval commercial fabric of Porto's Ribeira district, where narrow frontages, continuous shopfronts, and multi-directional stairways produce high navigability through spatial density and programmatic variety. Second, Álvaro Siza's Bouça Housing complex (SAAL, 1973–2006), where the ground floor mediates between individual dwelling and collective urban life through carefully calibrated thresholds—covered passages, raised pilotis, and permeable courtyards—that negotiate the public-private gradient without suppressing traversal. Third, a contemporary ground-floor conversion in Porto's historic centre, where the replacement of a traditional commercial rés-do-chão by a sealed tourism unit exemplifies navigability collapse through simultaneous reduction of differentiation and increase of resistance.

The contribution is twofold. Theoretically, the article offers architectural criticism a falsifiable criterion for ground floor quality: a design intervention succeeds if it measurably increases the navigability of the threshold by expanding perceptible alternatives or reducing traversal resistance, and fails if it does neither. Practically, the framework provides urban designers with a diagnostic tool for identifying where and why ground floors cease to function as thresholds—and how they might be restored. The article concludes that a city which enhances its ground floors is one that structurally expands the paths available to those who inhabit it.

Navigability as co-operative measure: how participatory housing amplifies spatial freedom

Gonçalo Melo

Architectural criticism of co-operative housing possesses rich qualitative vocabularies — participation, empowerment, community, spatial quality — but no falsifiable metric for evaluating whether a co-operative process produces measurably more navigable environments than top-down alternatives. This article proposes one.

The article introduces a formal framework in which a building's navigability is measured by the ratio F = P/D, where P (Perception) designates the number of distinct path-classes an inhabitant can differentiate and how many steps ahead they can plan, and D (Distortion) designates the structural resistance — spatial, procedural, informational, and temporal — that the built environment imposes on traversal. The framework draws on Shannon's information theory (1948) to quantify Perception as P = log₂(N) × T, where N is the number of distinguishable continuation classes and T is the predictive depth in processing cycles. Distortion is measured independently, following Hillier's configurational analysis (1996) extended to include bureaucratic, informational, and temporal resistance dimensions.

The article's central argument is that co-operative housing processes amplify P before construction begins. When future residents participate in site selection, unit layout, and communal space distribution, they acquire differentiation capacity — the ability to distinguish among available paths within their own environment — that non-participatory residents take months or years to develop, if they develop it at all. Participation is formalised as pre-construction Perception amplification: navigational education embedded in the design process itself.

Three Portuguese case studies are analysed as navigability fields with calculable F-values. Álvaro Siza's SAAL Bouça in Porto (1973–2006), a co-operative social housing project initiated under the participatory SAAL programme following the Carnation Revolution, is compared with a peripheral social housing estate of the type constructed through top-down allocation in the late 1990s, and with Siza's Faculdade de Arquitectura da Universidade do Porto (1987–1996) as a control case of non-residential architecture that rewards inhabitation. Each building's Distortion is estimated across spatial, procedural, informational, and temporal dimensions. Each population's Perception is calculated from observed continuation classes and anticipatory planning depth.

The results reveal a Freedom ratio of approximately 59:1 between Bouça and the peripheral estate — both publicly funded social housing for comparable populations. The article identifies precisely where the difference lies: Bouça's moderate Distortion (clear linear organisation, human scale, urban connectivity) and high Perception (participatory process, legible spatial logic, integration with metropolitan transport networks) versus the estate's extreme Distortion and structurally suppressed Perception. A distinction between destruction-based intervention (reducing D through demolition) and conversion-based intervention (amplifying P while transforming D) demonstrates that conversion achieves approximately fourteen times more navigability improvement at a fraction of the cost.

The article concludes that co-operative housing's measurable advantage lies not in ideological commitment but in structural mechanism: participation amplifies the inhabitants' capacity to perceive available paths within their own environment, producing navigability gains that persist and compound through stigmergic layering — the accumulation of navigational knowledge deposited by successive inhabitations without centralised control.

ACESSIBILIDADE ESPACIAL EM EDIFÍCIOS DE USO PÚBLICO E COLETIVO NO BRASIL

CAROLINA STOLF SILVEIRA

A acessibilidade espacial em edifícios públicos constitui condição essencial para a efetivação do direito à cidade e à cidadania, conforme preconiza a Lei Brasileira de Inclusão (Lei nº 13.146/2015). Este artigo apresenta os principais resultados da experiência em pesquisa desenvolvida entre 2023 e 2025, realizada em convênio com o Ministério Público de Santa Catarina - MPSC na avaliação das condições de acessibilidade espacial de 22 edificações públicas de Laguna/SC/Brasil, abrangendo equipamentos de saúde, institucionais e educacionais. Realizou-se vistorias in loco com aplicação de planilhas de verificação com estudantes de Arquitetura e Urbanismo, trazendo o conhecimento técnico e teórico abordado em sala de aula para a prática em situações reais. Os resultados evidenciaram recorrência de barreiras no meio urbano, nas circulações, sanitários e na comunicação e sinalização, comprometendo orientação, deslocamento, uso e comunicação de todos os usuários e de forma mais agravante àqueles com deficiência físico-motora e sensorial. A pesquisa evidenciou a necessidade urgente de adequações físico-espaciais e de políticas públicas que de fato façam valer as normativas e leis de acessibilidade vigentes.

Rethinking Domesticity

Marta Malinverni

In Belgium during the early 1970s, pioneer cohousing projects emerged advocating alternative living arrangements. These initiatives, typically comprising small communities of ten to twenty households, fostered collaborative ways of living and challenged dominant economic and housing paradigms. Beyond redefining residential models, they also played a key role in reshaping gender roles by promoting women's autonomy, redistributing domestic responsibilities, and expanding their role within their households, their communities, and society as a whole.

This study examines the extent to which cohousing initiatives genuinely contributed to women’s emancipation, adopting a two-generation retrospective perspective. A dual methodological approach is employed, combining architectural analysis of selected case studies with ethnographic research. It assesses whether these resident-driven initiatives effectively promoted gender equity and the redistribution of domestic labour. By evaluating both their successes and limitations, this research explores how collective living arrangements restructured family dynamics, supported feminist objectives, and contributed to enduring social transformations.

The findings reveal that cohousing projects enabled women to challenge traditional domestic roles, engage in more equitable communal living, and cultivate independent lives beyond the home through the structural and social dynamics of their dwellings. A feminist analytical lens highlights how shared spaces in Belgian cohousing projects of the 1970s and 1980s fostered a broader cultural shift toward gender equity and collective empowerment. However, sustaining these egalitarian ideals over time posed significant challenges. This study thus offers insights into the long-term impact of cohousing on gender roles and its continued relevance for contemporary debates on alternative living models.

9 de Julho Occupation: proposal for new housing paradigms

Claudio Valente

Este artigo integra a pesquisa desenvolvida no âmbito da tese de doutorado intitulada [identificação do título e escopo da tese omitida para fins de avaliação cega por pares]. O estudo visa contribuir para o debate sobre habitação urbana por meio da análise da ocupação de prédios vazios localizados na região central da cidade de São Paulo. Com foco na “Ocupação 9 de Julho”, o artigo investiga como essa forma de apropriação do espaço urbano opera como um contraponto à lógica mercadológica e segregacionista da produção e do uso da cidade, bem como seu potencial para a construção de novos paradigmas de habitação.