We have an industrial building of office and manufacturing on both the first and second floors. The building is for a single tenant. The Lobby area has a large staircase that you can take to get to the second floor offices and manufacturing areas. My thought is that the square footage of the lobby area and the square footage of the staircase should be calculated into the total square footage of the building. Do you have a document that explains the calculation? If you do, that would be helpful to receive at email@example.com or a call at (949) 275-0615.