'Hybrid projects' is a phrase, used for the benefit of this research, to define a type of adaptation project where new elements or buildings are combined with existing buildings to completely modify it in order to provide better functionality and meet increased spatial requirements. It is the adaptation of an existing building through a combination of refurbishment, rehabilitation and adaptive reuse. The main challenge that designers face with hybrid projects is the quality of relevant yet qualitative 'as-built' information. In instances where original architectural and engineering drawings and details are available, it is highly probable that the building will have evolved to the extent that the historical drawings are no longer accurate. The design proposals produced with this information may then lead to problems during construction. This research investigated the impact of inadequate feasibility studies and surveys conducted on hybrid projects.