Abstract

Housing in Colombia, especially social housing, has been a priority issue for governments in recent years; however, it is necessary to consider building more sustainable homes with less environmental impact using local material as opposed to building with conventional materials. Based on these needs, this research aimed to evaluate the potential environmental impact of social housing by predominantly using local resources in the construction phase and surplus resources, such as rainwater and graywater, in the use phase. As a case study, a real social house in the city of Pereira (Colombia) was selected; this house was built by an institutional housing program 15 years ago. From the records of this housing project, it was possible to quantify the local resources used to build the house, which were mainly bamboo (Guadua angustifolia Kunth) and clay tile. Then, new social housing was modeled that used rainwater and reused graywater in non-potable uses during a life cycle of 50 years. In this scenario, we found that the use of local materials in the construction phase of housing and the combination and use of alternative water resources (rainwater, graywater) for domestic non-potable use can decrease the potential environmental impact of building and maintaining this type of housing. This decrease was equivalent to a decrease of 10.9% (Global Warming Potential [GWP] of 137 kg CO₂ eq./m² built) in the total potential greenhouse gas emissions for comparable conventional social housing. The use of local materials and surplus resources (rainwater and graywater) during the life cycle of low-density housing contributes to the emission of fewer greenhouse gases. Additionally, it was observed that the use of local materials for housing projects strengthens local employment options.

Key words: Life cycle analysis (LCA), graywater, rainwater, urban water, bamboo.