This paper considers the impact of user-initiated housing extensions on the use, function and appearance of the urban space. Interested in the urban tissue, rather than in single buildings, the paper, based on post-factum evaluation, examines the communal effect of user-initiated extensions, rather than the individual benefits to the household. It seeks to understand the dichotomy between the freedom of owners to transform their dwellings and the negative impact such freedom might have on the quality of the immediate residential environment and on the public domain. The findings indicate that had the residents understood the implications of their actions they would have readily chosen the more burdensome route of design control. This suggests the need to pre-plan and coordinate housing extensions to moderate the negative effects of individual extensions on the public space. Toward this, it is important to include residents in planning processes by involving them in decision-making, informing them about opportunities and drawbacks, while assessing their potential to absorb change.