At this early stage, it may be very useful to schedule several work sessions for yourself and/or individual staff at another nearby library that is housed in a new facility. That way, you will be able to be more objective about your own building and prevent yourself from trying to find 'band-aid' solutions.
An adjacency is a relationship between two or more functional areas. For example, the children's staff workroom would probably be adjacent to the children's library. Adjacencies are expressed by a matrix or a diagram, or both.
Think carefully about your adjacencies (examples indicated by a •), and also about "negative adjacencies" or separations (examples indicated by an X). Teen users generally don't want to go through the children's library to get to the teen room, and the storytime room should not be next to a quiet study space.
A simplified Adjacency Matrix:
An Adjacency Diagram, often called a Bubble Diagram for obvious reasons:
Note: the bubble sizes and locations are very approximate. It's the connecting lines -- the relationships between spaces -- that should be your focus.