The paper means to explore how people use and perceive the shop house corridor as the most built environment found in Medan, Indonesia. The research observed the adaptation and or adjustment pattern of people in their built environment. The study did an interview with users of the space to get people perception of the built environment quality. The result indicates that people used space mostly for market activities, in particular for the mobile street vendor. The users make some adaptation to fit their needs. They “divided” urban space and mark their territory based on the “unwritten agreement” and tolerance.