A growing body of evidence suggests that the most common barrier to achieving design intent is the absence of comprehensive information during design development, leading to poor decision-making which impacts on actual building performance, and thus Whole Life Cost (WLC). Building Information Modeling (BIM) has the potential to facilitate a more comprehensive and accurate design approach from the early stages. A detailed model can allow designers and clients to understand the wider impacts of design changes, and to track this information through construction stages. However, dependencies between design decisions and WLC have yet to be understood. This paper is based on a project that focuses on the Private Rental Sector (PRS), which is the fastest growing new sector in the UK housing market. The study adopts a mixed method approach for the development and validation of a structured standardised process for timely WLC estimation through BIM. As a result, the main problems in WLC BIM management are identified, and coordinated into a reverse-engineered systematic process that uses the Integrated DEFinition (IDEF) 3 structured diagramming modeling technique. The research outputs aim to enhance BIM lifecycle management through a smart decision-making approach that is integral to the natural design development process.