How can we invite children and young people into the design of their everyday environments in a meaningful way? How can we facilitate real collaborative decision-making processes that simultaneously are manageable and produce actual physical built results? Involving children in the design and planning of their everyday environment is a practice that has been explored and experimented with in various setups. Challenges arise when actual design-based decision-making is integrated into a real live building process with its complexities and extensive procedures. They often fall short when translating thoughts and ideas into tangible physical space. Either children’s contributions end up as sketches on a post-it note or the time gap between the design workshop and the completed built space is so extensive that it no longer seems relevant for the involved children and partners. This case study practice review presents a co-design process with a group of children that took place in the social housing estate Hørgården, Copenhagen, during spring of 2021. The paper unpacks our method testing how design decisions can be negotiated and lead to the collective design and construction of three social urban furniture. A key element is to discover if and how children felt a sense of ownership of the process and the outcome. For this, we use field notes and photo documentation along with interviews with stakeholders and children. The topics touched upon in this paper illustrate relationships between the different SDGs and their targets in a concrete community-driven co-design partnership.