Construction Cost Estimate and Building Information Modeling in Renovation Projects Early Design Stages

The evaluation and control of building costs accompany real estate projects from the initial planning phase to the end of the construction stage. Each phase of project development is associated with distinct estimation methodologies, characterized by an increasing level of accuracy as the design progresses. Estimating construction costs during the early design stages is one of the most critical challenges in real estate and infrastructure investment planning. At these stages, detailed cost estimates based on bills of quantities are always unfeasible, as project information is typically limited to concise descriptions of functions and dimensions. Consequently, assessments rely on parametric methods, which involve identifying one or more reference buildings with similar characteristics to the planned one, using historical data on its costs as a basis for estimation. The cost of the reference buildings can be sourced from market monitors or specialized publications, such as building cost inventories. These inventories, in addition to providing construction costs divided by groups of work items, typically include key dimensional data, works brief description, and project excerpts. This study presents the results of BIM modeling for one of the buildings included in an inventory widely used in Italy, aiming to explore the potential of this technology to enhance cost estimate accuracy in the early design stages. The accuracy of parametric estimates based on data from the inventory and those derived from the BIM model is validated by comparison with a case study, for which the construction cost has been assessed through a bill of quantities.