Retrofit adaptive envelopes : a systematic series of strategies in informal settlements in Tshwane, South Africa

Abstract

Climate change risks have resulted in ambient temperatures in South Africa rising at close to double the global rate. South Africa has a significant proportion of its population residing in informal settlements with high vulnerability to heat stress conditions. The study assesses and addresses the effectiveness of retrofitted bioclimatic façade adaptation strategies to mitigate heat stress in informal dwellings in Tshwane, South Africa. The primary objective is to examine the synergy of these strategies in reducing indoor heat stress exposure. Climate-responsive buildings that adapt to changing conditions can significantly improve user comfort during extreme weather events. Adaptive façades, which reduce energy consumption and heat stress, are particularly relevant in urban informal settings where access to electricity and conventional methods is limited. An observational analysis of 23 informal dwellings identified and evaluated common heat amelioration strategies along with insights from existing literature, including cross-ventilation, overhangs, vegetative solar shading and cool coatings. Strategies are synergised and assessed based on their performance, considering the annual percentage of hours experiencing heat stress. Combining strategies of cool coating, cross-ventilation, and vegetative solar shading significantly lowers heat stress exposure under current climatic conditions by 82% as well as predicted 2100 Intergovernmental Panel on Climate Change (IPCC) climatic conditions by 51%. The study contributes to the discourse by highlighting the need for synergised adaptive strategies for informal settlements to improve thermal performance and climate resilience. As well as offering insight to future governmental policymakers.