Codes and Conventions for Future Zurich: A Propositional Planning Approach to Qualitative Densification

Prof. Tom Avermaete (ETH Zurich) and Prof. Jonathan Sergison (AAM)

Codes and Conventions for Future Zurich:
A Propositional Planning Approach to Qualitative Densification

September 2021-August 2025
Funded by Swiss National Science Fund

A research proposal by Prof. Jonathan Sergison (AAM) and Prof. Tom Avermaete (ETH Zurich) has recently received funding from the Swiss National Science Fund. This 4-year project uniquely combines historical and design-led research to explore urban strategies for housing the anticipated 25% population increase that Zurich is facing in the next 20 years. A ‘retroactive analysis’ of the historical evolution of building codes, as well as of the specific urban types and morphologies they have generated, will offer the basis for ‘propositional planning’ investigations of their required future adjustment to allow for a process of densification to occur while maintaining urban quality.

This project is undertaken collaboratively with ISUP, AAM and gta, ETH Zurich. Prof. Sergison and Prof. Avermaete will be working with Dr Irina Davidovici as project partner, and with two doctoral students and a postdoctoral project coordinator.

Background and rationale
In the next decades, the city of Zurich anticipates a population increase of 25% over current numbers. Finding the means of housing, collective services, public facilities, recreational spaces etc. to accommodate the growing population is only one of the city’s future challenges. Alongside it, engaging with changing dwelling patterns, altering mobility practices and mitigating climate change all require a new integrated perspective on urban development. The Spatial Planning Law that came into force in 2014 prioritises densification over expansion, but how can Zurich’s densification be realized without a loss of urban quality?

The main hypothesis of this research is that predicted growth can be absorbed within Zurich’s territorial limits within pre-developed urban scenarios for qualitative densification. We hold that the investigation of such scenarios requires:
a) a refined understanding of the relation between ‘urban codes’ and ‘urban tissues’ and
b) should proceed through an architectural methodology, which addresses the concrete spatial characteristics of the urban tissue as the expression of social, environmental, economic and mobility concerns.

Taking as point of departure the current Zurich Richtplan (Stadt Zürich 2018), the central focus of this project will be on the relation between urban tissues and urban codes. We understand ‘urban codes’ as the various building regulations, plans and policies generated at several levels of urban governance (state, canton, city). We hold that these urban codes not only determine the formal characteristics of the urban tissue, but also implicitly define a project for the city: in the various definitions of the urban codes a large set of assumptions are embedded that ‘speak’ of specific cultural ideals of living, environment, recreation, working and mobility. Hence, though these urban codes are very often extremely technical in character, their implications reach far beyond.

This project has two goals. Firstly, we aim to reveal the hidden project for the city that is embedded in urban codes. We aim to understand how the different assumptions (social, environmental, economic, concerning mobility) implied in the urban codes have affected Zürich’s urban fabric since the 19th century until today, namely the reciprocal relation between the form of the current city and the definition of the urban codes. Secondly, we aim to explore – through design-led research – innovative models of qualitative densification, and identify the revisions to urban codes necessary to obtain this qualitative densification.

The project will examine the relation between urban codes and urban tissue both from a retrospective vantage point and from a future-oriented perspective, through the unique combination of historical (ETH) and designerly (AAM) research. What we coin respectively ‘retroactive analysis’ and ‘propositional planning’ are interrelated through a set of common research foci. The ETH team will undertake the retroactive analysis of Zurich’s urban tissue, starting from the current condition to understand the generating logics of its codes. At AAM, propositional planning scenarios will be developed through urban design projects related to the critical analysis of urban codes. Retroactive analysis focuses on how cultural patterns have influenced the definition of urban codes, while propositional planning explores the limits of the existing urban codes and the urban tissues they might lead to.

In addition to the envisaged doctoral theses and scientific articles, the ETH and AAM teams will each produce a substantial synthetic outcome, respectively the historical Zurich Retroactive Atlas and the prospective Propositional Planning Primer, both addressing policy makers, planning experts and architectural practitioners, as well as stakeholders and the wider public.

Dr. Irina Davidovici