When designing space, architects and designers reproduce contradictions of activity into contradictions of space. The opposite can also be said; that people using and transforming space reproduce contradictions of space into contradictions of activity. The thesis reports on observations and experiments in designing and using spaces with contradictions included, for example, by playing games that make contradictions present to the senses. These studies were conducted in the context of architectural and service design projects from both academia and industry. The conclusion is that contradictions included pushes design beyond what was thought to be possible, effectively creating new possibilities for collective action. Abstract: This PhD thesis looks at the practice of design as it emerges in architectural design and service design. The lens adopted considers design both as an activity as well as a space full of contradictions, which are accumulated tensions. Design activity is a professional occupation that interacts with other activities, whereas design space is a range of possibilities considered for a project. The contradictions in both sides are separately identified and then rejoined to follow the transitions from one side to another. When pursuing this dialectic, this research has found two ways in which design reproduces contradictions in society. The first, reductive design, aims to reduce contradictions by partitioning the design space into small manageable parts. The second, expansive design, aims to expand contradictions by increasing awareness for the possibilities in the design space. The former ignores, hides, or removes contradictions from the design space and the later uncovers, highlights, or takes advantage of contradictions in the design space. The combination of reductive design and expansive design leads to uneven development. This understanding of design comes from three short-term empirical studies of architectural design and service design projects, which were complemented with two experiments undertaken with design students. The empirical studies show evidence that expansive design may emerge from playing design games; however, this also depends on the willingness of participants to deal with contradictions in an inclusive way. The main contribution of this thesis is highlighting and developing further the concept of expansive design, which implies dealing with contradictions in an inclusive way.