Building additions

Michael, the answer to your question depends on whether or not a major renovation is being undertaken, which would determine whether or not the project would qualify for LEED for New Construction and Renovations, or LEED for Existing Buildings: Operations & Maintenance. How much of the square footage is involved and will the occupants be displaced? If most or all of it, then LEED-NC is the best system. As long as you are not building an addition that is more than 2X the size of the original building, you should qualify for building reuse.