Applying of BIM methodology (see Fig. 1) to existing constructions does imply, first of all, a thorough study of
the documentation and then an accurate analysis of the true state of the building. The mapping of residual
performances provides the basis to proceed with the evaluations of the interventions in order to realign the building
to the current rules and with the planning of its ordinary and extraordinary maintenance operations. In the building,
the structural, architectural and system models allow for instance seismic-dynamic analysis, energy or noise analysis
and encourage to design targeted interventions, very tailored to the weaknesses and the specific needs of each
building element; the goal is to assess in advance the investment impact in terms of benefits, costs, implementation
timing and payback time as well.