Purpose: The adverse impacts of climate change coupled with rapid informal urbanization in the Southern African region are increasing the vulnerability of already sensitive population groups. Consequently, these urban regions are highly vulnerable to urban heat island effects and heatwaves due to exogenous and endogenous factors. While the dynamic interplay between the built environment, climate and response strategies is known, this paper highlights the lived experience of informal settlement residents. It presents work from a project undertaken in Melusi, an informal settlement in Tshwane, South Africa, as a multi-disciplinary project focusing on improving the local resilience to climate change associated heat stress.Design/methodology/approach: Following a mixed method approach, a semi-structured observational analysis of the spatial layout and material articulation of selected dwellings along with the continuous monitoring and recording of their indoor environments were undertaken.Findings: The paper presents the research results in terms of the dwelling characteristics, as spatial and material-use strategies and documented heat stress exposure in these structures. The findings highlight that informal dwellings perform poorly in all cases due to endogenous factors and that inhabitants experience extreme heat stress conditions for between 6 and 10 h daily during the peak summer period.Originality/value: Currently, there are little empirical data on the heat stress residents living in informal settlements in Southern Africa are experiencing. This article provides insight into the indoor environments of informal dwellings and hopes to contribute future guidelines or heat health policies.

Globally urbanization is accelerating, especially within developing countries. This often results in vulnerable urban conditions with limited adaptive capacity to respond to climate change-induced hazards. In response, employing innovative solutions that lever existing unused and underutilized interstitial spaces within the urban fabric for climate change adaptation and mitigation purposes are needed. Essential to this strategy is a better understanding of the quantity and type of potentially available interstitial space. Using a mixed-method approach, this paper analysed the spatial and material condition of unused and underutilized interstitial spaces within a Southern African city. This study organizes these interstitial spaces according to programme, zoning, access, spatial definition, microclimatic characteristics and material use. It undertakes a quantitative assessment identifying seven specific interstitial space types, found in the total study area. Underutilized parking spaces and rooftop spaces are identified as the most prevalent space types with significant climate change adaptation and mitigation potential if appropriately retrofitted. Retrofitting these spaces are relatively effortless, and can ultimately improve the climate change resilience of these cities.

While climate change represents a universal threat to the sustainable growth efforts globally, its impacts are not experienced equally with marginalised population groups, especially informal settlement residents, being highly exposed to its negative effects. Despite being widely acknowledged that the built environment is a major driver of inhabitants’ exposure to climate change-related hazards, limited research has been undertaken on developing heat stress adaptation measures for informal settlements in Southern Africa. Furthermore, Africa’s projected rapid urbanisation and limited adequate housing provision point to a significant growth of informal settlements, particularly within the Southern African context. The dearth of available information on household level climate change adaptation in informal settlements prompted this study to investigate the efficacy of roof-based adaptation strategies to lower heat stress exposure in informal dwellings in Tshwane, South Africa. As an explorative study with a quantitative focus, the study uses a digital simulation research design to assess the efficacy of four climate change adaptation strategies to lower heat stress exposure in two typical informal dwellings as case studies. While informal settlements have diverse building typologies, informal dwellings – frame structures cladded with steel sheeting without any thermal insulation – are widely used and highly vulnerable. In contrast to typical adaptation measures proposed for informal dwellings, the main findings highlight the benefit of high thermal mass coupled with shading strategies to lower thermal amplitudes and lower excessive heat stress exposure. Consequently, the article contributes to the current climate change adaptation discourse, in particular its application in informal settlements.

Since low-income and social housing are among the most vulnerable built environments to climate change, this article evaluates the energy performance of social housing in the context of enabling net-zero carbon social housing in South Africa (SA). It seeks to investigate how improved and conscious energy-efficient design in the context of social housing contributes toward a climate change mitigation response in SA. The article analyses energy use and indoor comfort, based on ASHRAE 55-2004 Standard, of two social housing case studies to review the potential of the social housing sector to contribute to the national climate mitigating agenda. The findings highlight that the housing provision itself is not an adequate response, but that bio-climatic design solutions with appropriate spatial and material choices, along with efficient envelope articulation, play a critical role in lowering energy use and improving user comfort. There is, however, a need to challenge the growing advent of (energy-) inefficient and carbon-intensive social housing in SA and simultaneously address the parallel crisis of homelessness, to enable a sustainable future for the built environment.