We are in a process of designing a 250,000 s.f. largely subterranean facility for the Pentagon, of which approximately 200,000 s.f. will be renovated existing structure projecting from the north face of the Pentagon, under a raised terrace. The roof structure of the existing portion of the building supports a large parking deck for high-ranking officials at the Pentagon and although the team is tasked with waterproofing the existing roof parking, the area is NOT open for modification or design improvements. The program calls for replacing exactly the number of parking spaces and they will not serve any users of the new facility. Therefore we consider this a rehabilitation effort and would like to exclude it from calculations of parking capacity for the project. The new facility includes a separate parking area providing space for six cars, which exceeds minimum local zoning, considering that proposed occupancy of the facility is +/- 2,000. Please confirm that our assumption is correct. Your ruling on the existing parking lot issue will affect other points that are listed for SS Credit 7.2.
You may exclude the roof deck parking area from parking calculations if it serves as existing parking capacity for a different building. LEED requires your project to "size parking capacity not to exceed local zoning requirements AND provide preferred parking for carpools serving 5% of the building occupants." You will have to demonstrate compliance with both these aspects of the LEED requirements to achieve this credit. Provide pre-rehabilitation parking plans and post-rehabilitation parking plans showing that no new parking has been added to that portion of the project that is considered rehabilitation; that parking at the new portion does not exceed the zoning minimum; and that the preferred parking for carpools requirement has been achieved to capture this point. Under SS credit 7.2, you may not exclude part of the roof structure from the heat island calculations even though it contains existing parking above. The area calculations for the roof system are based on the entire roof of your building and require that 50% of the total roof be vegetated, or that 75% the surface meet Energy Star requirements.