For the LEED Online form, one of the last sections asks you to explain what alterations and additions were done to the building and give a value for the floor area under construction. I understand that the purpose of this section is to show that a significant amount of work was done to warrant points for this credit (this isn't exactly my concern). If our building had all new exterior siding and a new roof, how would I go about calculating this? Would it be 100% of the floor area because 100% of the roof is new? How can I calculate area for work done on the perimeter of the building?