We are doing a project that has 3 buildings out of which one is a two storied building. The proposed facility alteration/ addition project is on the upper floor of this two storied building where the client intends to build a mezzanine floor.

My question is when we calculate the 5% minimum requirement for the facility alteration/ addition project, should I calculate it using the total building floor area or the floor area of the upper floor only?

Or should I use the total floor area of all 3 buildings in my calculation?

Thank you.