This paper contributes to the understanding of how critical reflection can be applied to sustainability. This was accomplished by tracing the progression of a tiny-house project over time and the associated activities, which involved sourcing secondhand and discarded materials. We are a group of researchers and practitioners who worked together to explore and challenge the established norms of sustainability in housing practices: who is building, what is being built, with what materials, and through which processes. The use of discarded materials as resources for building a tiny house came to be decisive in shaping a platform for inclusion and sustainable practices. While the most common practice of building involves buying the materials needed at a lumber yard, working with discarded and secondhand materials requires time and flexibility. Tools play a central role in adapting random waste to specific purposes, a process that also demands skills in handling tools creatively. Additionally, gathering, organizing, and cleaning are activities that should be given special attention when working with these types of materials. In this paper, we explain how we reinjected waste materials into the production chain and how our work contributes to sustainable development from environmental and social perspectives. The argument for sustainability in our research revolves around exploring processes that include more groups in society and alternative ways of organizing the resources available.