A master key system means each door has its own key that opens only that door, and one master key opens all of them. A manager carries one key instead of fifteen. Staff carry keys that work where they need to work and nowhere else.

It sounds simple, and mechanically it is. The part worth getting right is the planning.

How the levels work

A system can have more than two levels. A common shape in a multi-floor or multi-department building looks like this:

Change keys. One per door, opening that door only. Most staff carry these.
Sub-master keys. Open a group of doors, a floor, a department, or a wing. A supervisor carries one of these.
Master key. Opens everything in the system. Held by whoever genuinely needs it, which is usually fewer people than you would think.

The right shape depends on your building and your staffing, not on a template.

Planning it before cutting anything

Most bad key systems were not designed badly. They were never designed at all. They grew a door at a time over ten years, and now nobody can say with confidence which key opens what.

Before cutting anything we map out what doors exist, who needs to get through which of them, and where that is likely to change. Then the system gets built to match. A system planned around your actual access needs still makes sense in three years. One assembled reactively does not last twelve months.

You also get documentation: a chart showing which key opens which door, and who is holding what. Most buildings we walk into cannot answer either question, and that document is worth as much as the hardware itself.

Interchangeable cores

Worth considering at the same time. IC cores pull out with a control key, so a door can be rekeyed in seconds rather than having the lock taken apart. In a building with regular staff turnover that difference adds up quickly.

Where a building already has them, we normally swap in new cores and issue new keys instead of reworking the old ones, which gives you a clean set with a known history. In practice, most buildings with IC cores no longer have the control key, which is another reason a fresh set is usually the cleaner route.

Where these make sense

Offices with multiple departments or floors.
Apartment and rental buildings.
Medical and dental practices with restricted areas.
Retail with stockrooms, offices and back-of-house.
Warehouses and light industrial.
Churches, schools and community buildings with mixed access.
Any building where somebody is carrying too many keys.

Keyways

We work with the common commercial keyways and stock and cut for them, including Schlage and Yale. If your building is on a restricted system such as Primus, mention it when you call so we can confirm what is possible before coming out.

Common questions

What is a master key system, in plain terms?

Every door gets its own key, and one master key opens all of them. You can add levels in between, so a supervisor’s key opens their area but not the whole building.

Can you build one using our existing locks?

Often yes, depending on the hardware and keyways. Where some doors have incompatible locks, those can be swapped so everything sits in one system.

What happens if the master key is lost?

That is the risk that makes planning matter. Depending on how the system was designed, it can mean rekeying everything the master opened. It is a strong argument for limiting how many master keys exist and knowing exactly who holds them.

Can we add doors later?

Yes, if the system was planned with room to grow. That is one of the things we look at before cutting anything, because retrofitting a door into a system that was not designed for it is the harder version of the job.

How long does it take to set one up?

It depends on the number of doors and the current hardware. Planning takes a conversation and a walk through the building. The work itself is usually quicker than people expect once the plan is settled.

Do we get a record of the system?

Yes. You get a chart showing what opens what and who holds which key, which is what stops the system drifting back into disorder over the years. We keep the technical detail on file so replacement keys can be cut later without it sitting in a drawer somewhere.

Master Key Systems