Through the 1987 Brundtland report “Our Common Future”, the UN popularised the concept of sustainability as, “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (WCED, 1987). This definition emerged from the pairing of ecological and social critiques of economic development, elaborating on the previous term “eco-development”, coined in 1975 as a merging of economic development with environmental integrity (Purvis, 2018).  

Indicators of Sustainable Development: Guidelines and Methodologies (2001) definition of sustainability divided the issue into three main categories: economy, society and environment; the original draft included the category institutional – incorporating societal and legal norms, cultural determinants of development, and procedures (Spangenberg et al, 2002).

Since then, a number of UN initiatives have been developed to encourage global cooperation of sustainable development: the declaration of a climate emergency (2016), the 17 Sustainable Development Goals (SDG) (2015) and the Paris Agreement (2016). 

When investigating affordable and sustainable housing, the issue must be approached holistically to satisfy the multiple facets of sustainability. Sustainability goes beyond the terms and goals pre-defined by the UN; the SDGs have been designed to provide a solid framework to justify and organise policy and action, and therefore have political agenda (Le Blanc, 2015).

In order to continually strive towards (and surpass) the SDG’s, sustainability should be considered throughout every stage of design, planning and building interventions and renovations. This should also include multiple scales, from material choice to construction methods and processes, and energy consumption (Berardi, 2012). Worldwide retrofit schemes, such as RetrofitWorks and EnerPHit, encourage sustainable and affordable housing through improving building performance, decreasing energy consumption and reducing fuel poverty. A further vital consideration in sustainable design is a reduction in Greenhouse Gas emissions; in developed countries, the construction industry accounts for 40% of total emissions (ibid).