Planning A Master Key System
In short: Design the schedule before buying hardware. Plan for the building you will have in three years, not the one you have today.
Start with a door list, not a hardware list
Write down every door and who should open it: tenants, cleaners, maintenance, management, emergency access. The schedule falls out of that list. Buying cylinders first and working out access afterwards is how systems end up needing a full rekey within a year.
Understand the levels
A change key opens one door. A master key opens a defined group. A grand master sits above several master groups. Most small buildings need two levels; adding a third should be a deliberate decision, not a default.
Fewer levels is stronger
Every level of masterage adds extra shear points inside each cylinder, which slightly reduces resistance to manipulation. A tight schedule with two well-chosen levels is more secure than one that masters everything to everything just in case.
Specify a restricted keyway
On a rental or commercial system this is usually the point. A restricted keyway means tenants cannot walk into a kiosk and cut extra copies, and key control stays with you. Without it, your careful schedule is only as good as everyone's honesty.
Document it and plan for growth
Keep a written keying schedule showing which key opens which door and who holds it. Leave expansion capacity in the design. Retro-fitting a level you did not plan for means rekeying cylinders that were working perfectly well.
About this guide
Written by A 24 Hour Locksmith, a licensed Sacramento locksmith. California Bureau of Security and Investigative Services License No. LCO 6830. License numbers can be verified on the California BSIS public license lookup. Nothing on this page is a priced offer; call (916) 244-3934 for an estimate for your situation.
Common questions
Can my existing locks be master keyed?
Often, if they share a compatible keyway. A mixed-brand building usually needs some cylinders standardized.
How do I stop tenants copying keys?
A restricted keyway. It is the practical answer, and it is why most rental systems specify one.
What happens when a tenant moves out?
You rekey that unit's change key. The master above it is unaffected, which is much of the point of the system.
Questions about your own locks?
Call and you will get a straight answer, whether or not it turns into a job.
Call (916) 244-3934