This thesis proposes facilitating the re-urbanization of Toronto’s avenues to support the future growth of Toronto. The current guidelines for avenues buildings set out in the Avenues and Mid-Rise Buildings Study is not flexible enough to support the current amount of density that is required to facilitate the re-urbanization of the avenues. The current typology is producing uncomfortable buildings, and there is minimal capacity to accept future demands on density. This thesis proposes managing the re-urbanization of St. Clair Ave. W through the addition of carefully assembled residential properties, located to the rear of avenue properties, to an avenue property assembly. This combined larger assembly will offer the capacity to redevelop larger buildings at greater densities, without significantly impacting the existing residential properties because the larger assembly also allows for greater flexibility in the distribution of building mass. The thesis proposes the development of two buildings, one on the avenue and the other to the rear on the side street. The larger avenue building can accept greater density and rear building will be low mid-rise building that will be the types of building envisioned by the city and form a buffer zone to the residential neighbourhood. This thesis is focused on facilitating incremental re-urbanization and is not concerned with large scale master planned multi-building redevelopments. The thesis is concerned with the mechanisms that drive urban form and not the final design of the building. The thesis presents building design guidelines to guide the urban form of these two buildings and presents what this might look like through diagrammatic representations of buildings on case study sites and using street perspectives. St. Clair Ave. W is only one of many avenues in Toronto planned for re-urbanization, and while each avenue is similar, they are all different. This flexible approach to accommodating redevelopment could be used to inform the guidelines for new development along many different avenues.