Decarbonization possibilities for affordable wood-framed houses in the south of the US. Comparison of conventional, circular, and regenerative options

Abstract

The transition to more circular practices in the construction sector offers an alternative path to the predominant linear, high-polluting, and wasteful processes. To better understand the full impact of building materials and buildings over their lifespan and beyond, life cycle assessment (LCA) studies have been a field of interest and a growing body of knowledge over the past three decades. Moreover, recent studies stress the critical relevance of the end-of-life (EoL) scenario, particularly for wood-based construction, highlighting its potential for further decarbonization through circular strategies such as design for adaptability, disassembly, and reuse. However, there is a significant knowledge gap in the LCA literature related to environmental impact mitigation strategies specific to affordable housing options, despite the pressing and undeniable need for these typologies. This study contributes to filling this gap by performing a detailed whole-building LCA of an affordable single-family house prototype built in the south of the USA using a standard light wood frame construction method. Besides the standard as-built scenario, this study developed five hypothetical scenarios that evaluated the influence of different EoL options (recycling or energy recovery), increased circular strategies (reuse), and substitution of non-renewable materials with regenerative materials for insulation (wood fiber) and finishing (clay plaster), aiming to identify further possibilities and limitations for decarbonization of such typology and construction method. The results of this study consistently pointed out that priorities should be to (1) guarantee proper end-of-life of metals and wood-based materials. (2) To replace non-renewable materials with regenerative wood or earth-based ones. (3) To improve material reuse and construction waste diversion rates. The results of this study support the development and implementation of policies and regulations for affordable housing, aiming toward increased environmental justice and a more equitable and sustainable built environment for all.