The cost of green roofs disposal in a life cycle perspective: covering the gap.

This study is aimed at providing a contribution in overcoming the current gap, especially in Life Cycle Costing (LCC) and Benefit e Cost (BCA) analyses, due to the lack concerning the green roof disposal costs. Therefore, we have applied to an actual extensive green roof the LCC methodology suggested by D. G. Woodward (that appears like one of the most formalized and generalizable), but we have extended the analysis to the disposal phase. This will allow a complete and proper application of the LCC methodology in order of achieving an economic accounting of this component through its life cycle. In this way, it is possible to achieve the complete evaluation of the “green roof” performance by a life cycle perspective (the environmental performances, in fact, are assessed by means of the classical Life Cycle Assessment approach). Needed steps for accomplishing the cost analysis of the disposal phase of this building component have been applied and discussed. These steps help to formalize the procedure, so attributing it an approach which may be generalized. The relative contribution of production, maintenance and end of life phases to the whole cost of this extensive green roof has been illustrated as well.