Cities of Flows : How construction and demolition shape building stocks, urban form, and material flows

Abstract

The construction sector is a major contributor to environmental degradation and the global climate crisis, driven by the extraction, processing, and disposal of vast quantities of materials. As hotspots of material turnover, urban areas are critical targets for reaching global sustainability goals. Finland, with one of the highest per capita material footprints globally, faces particular challenges amid urban growth predictions. The goal of this doctoral dissertation is to get a better understanding of two Finnish urban building stocks and their dynamics to inform decisionmakers in developing more resource-conscious urban development strategies.

The subjects of this dissertation are the two Finnish cities Tampere and Vantaa and how the cities’ building stocks have changed through construction and demolition between 2000 and 2018. Through a comprehensive bottom-up approach, this research dissects the target building stocks to identify building-type-specific patterns. These are further investigated in relation to population growth, economic development, and context-related factors, revealing how shifts in the demand for different building types influence the overall building stock composition and its dynamics.

This work builds on the premise that urban planning plays a pivotal role in shaping urban form which gives rise to construction and demolition. To explore this relationship, a novel spatiotemporal framework is introduced that links urban development patterns with construction, demolition, and building stocks. Leveraging Geographic Information System (GIS), the framework attributes building stock dynamics to four key urban developments: greenfield development, infill construction, replacement, and shrinkage.

A key contribution of this dissertation is the development of a new dataset of material intensity coefficients (MICs) for Finnish residential buildings. Enabling material estimations of buildings, these coefficients are essential for bottom-up assessments of material stocks and flows. The new MICs were applied to Vantaa to quantify material stocks and flows embedded in the city’s residential building stock and associated with their construction and demolition. By linking these findings to the spatiotemporal framework, this study unveils the material implications of the residential building stock dynamics in conjunction with the city’s morphological evolution.

The spatially refined approach suggests that land availability had a critical impact on urban planning decisions which led to distinct development patterns. The low availability of undeveloped land in Tampere, partially due geographical constraints, led to a replacement-oriented approach characterised by higher demolition rates. In consequence, non-residential buildings were often replaced with high-density blocks of flats to accommodate housing needs of the city’s growing population. In contrast, Vantaa’s more rural character allowed for greenfield development, resulting in lower-density developments with a higher share of detached houses. Such different local planning strategies not only shaped urban morphology but also led to distinct building and material stock dynamics.

Overall, this research visualizes how the diverse building types respond differently to various drivers and contextual factors. Understanding such building-type-specific dynamics is essential for formulating context-sensitive circular economy strategies. For example, residential buildings seem to be apt for design approaches that accommodate future extensions. In contrast, warehouses—often subject to relocation or replacement—may benefit from design-for-disassembly strategies. Urban planning plays a critical role in enabling such strategies by adopting a more building-life-cycle-oriented and flexibility-centred approach, ensuring that building stocks respond dynamically to various future changes in the demand for building services.