Master key systems: the right keys for the right doors

What this covers

A master key system lets different people carry different keys for the same building. Each staff member's key opens only the doors they need, a manager's key opens a group of doors, and the owner's key opens all of them. It replaces a ring of separate keys with one key per person, and it gives you control over who can open what.

How we approach it

A master key system starts from a map of the building: every lock, the doors each person or role needs, and the areas that should stay restricted. From that map, each lock is set up to work with the right keys, and each key should open its own doors and none of the others. Keep a written record of which key opens which doors.

Where it stops

A master key system is mechanical: locks and keys. It does not include electronic systems, and it does not replace good key control, because keys handed out without a record soon undo its value. When a key goes missing, the cylinders it opened can be changed without touching the rest of the building, which is one of the main reasons to have one.

The record is the most important part of a master key system. Keep a list of every key, its number, the doors it opens and who holds it, and update it every time a key is issued or returned. Without that list, a master key system slowly turns back into a pile of unknown keys, which is the problem it was meant to solve.

Plan for growth. A system set up for today's doors should leave room for the rooms and people you may add. Adding a new office or a new level of access later is simpler when the system was planned with room to spare, so mention planned changes before the locks are set up.