The situation that Niall describes sounds a little iffy. As he alludes to, it states in the Rating System Selection policy (located here: http://www.usgbc.org/ShowFile.aspx?DocumentID=6667) that 60% of the certifying gross floor area should be undergoing alteration work, and 'alteration work' is defined in the glossary. Obviously, policy can't be written to address all situations - usually, when a project is borderline, we just ask the project team to make the decision that works best for them. But I'm not sure that this is the case here. Niall, I would suggest that you send us a description of the work being done on your project, including a clearly labeled floorplan showing what kind of work is being done where. This can be sent to leedinfo@usgbc.org.