Embodied life cycle impacts of lightweight building methods for affordable houses in the USA: Comparison of conventional, circular, and regenerative strategies

Abstract

The transition to more circular practices in the construction sector offers an alternative to linear processes that are highly polluting and wasteful. Recent life cycle assessment (LCA) studies emphasize the relevance of the end-of-life scenario, highlighting its potential for impact reduction through circular strategies. There is an urgent need to fill the knowledge gap in the LCA literature on reducing the environmental impacts of affordable housing. Whole-building LCAs of three affordable homes built using a variety of lightweight construction methods in the southern United States were conducted to examine the environmental impacts of commonly used construction solutions for single-family affordable housing in the southern US and assess the extent to potential environmental impact mitigation through the introduction of additional circular strategies or the use of regenerative materials. In addition to the conventional as-built scenario, five hypothetical scenarios were considered in this study to evaluate the influence of different end-of-life options, namely, reduced recycling rates, increased recycling or reuse rates, and substitution of conventional insulation or finish materials with equivalent options from regenerative sources. The study aims to identify further opportunities for and limits to impact mitigation. The results show that the design and construction priorities should be (1) promoting proper end-of-life strategies for metals and wood-based materials, (2) replacing non-renewable materials with renewable wood or earth materials, and (3) increasing the reuse rate of materials and diverting construction waste. The study findings will support decision-making processes concerning the design and construction of low-impact affordable single-family homes and the development and implementation of affordable housing policies and regulations, resulting in greater environmental justice and a more equitable and sustainable built environment.