Is a Master Key System Worth It for a Strata Building?

October 31, 2026

Yes, for most strata buildings. A master key system lets each resident hold one key for their own lot while building managers and contractors hold keys that open only the common areas or plant rooms they need. Without one, buildings accumulate dozens of uncontrolled keys across residents, cleaners, trades and agents. The main risks are poor hierarchy design and building on an unrestricted key profile, both of which are avoidable at the design stage.



Strata buildings have an access problem that single dwellings do not. A house has one household and a handful of keys. A thirty lot building has thirty households, a building manager, a cleaning contractor, a gardener, a lift servicing company, a fire safety inspector, an owners corporation committee and a managing agent, all needing different access to different parts of the same property. Handled with ordinary keying, that becomes an unmanageable set of key rings very quickly.

What the System Actually Solves

Residents carry one key.

A single key opens the street entrance, the lobby, their own floor if access is controlled, the bin store, and their own lot. Without a system that is four or five separate keys per resident.

Contractors get scoped access.

A cleaner's key opens common areas and the bin store and nothing else. A lift technician's key opens the plant room and nothing else. Scoped access is the single largest security benefit, because it means handing someone a key is no longer handing them the building.

Management holds an override.

The building manager or committee holds a master that opens common areas and plant, which is necessary for emergencies and inspections, without holding keys to individual lots.

Lot owners retain privacy.

Well designed strata systems deliberately exclude individual lot doors from the building master. Owners corporation access to common property does not and should not extend to inside private lots.

Designing the Hierarchy

This is where strata systems succeed or fail, and it is a design decision rather than a hardware one.

Grand master.

Held by very few people. Opens common areas and plant. Should not open individual lots.

Sub masters by function.

A cleaning sub master, a maintenance sub master, a plant sub master. Each opens a defined group and nothing beyond it. This is what lets contractor access be revoked by rekeying one group rather than the whole building.

Change keys.

Individual lot keys, held by residents, opening their own lot plus whichever common doors residents are entitled to.

The error most commonly made is building too many levels because the structure looks tidy. Each additional level adds master wafers to every affected cylinder, and each wafer marginally reduces resistance to manipulation. The hierarchy should be as shallow as the actual access requirements allow.

Restricted Profiles Are Not Optional Here

In a single dwelling, a restricted key profile is a sensible upgrade. In a strata building it is close to essential.


A thirty lot building has at minimum thirty resident keys plus contractor and management keys in circulation. On an unrestricted profile, any of those holders can have a copy cut at a kiosk for a few dollars, with no record and no authorisation. Over a few years the number of working keys to the common areas becomes genuinely unknowable.


A restricted profile means blanks are supplied only to the authorised locksmith holding the system, who verifies entitlement before cutting and records every key issued. The owners corporation can then answer the question of how many keys exist, which is otherwise unanswerable.

The Cost Question

Strata systems are quoted on specification rather than from a price list, because the variables are the number of cylinders, the number of hierarchy levels, and the cylinder grade.


What is worth weighing it against is the alternative cost. Rekeying common areas in a building with no key control, after a key goes missing, means every resident needs reissuing. That is a significant exercise and an owners corporation expense. A restricted system reduces how often that becomes necessary and limits the scope when it does.


Adding capacity for future expansion at the design stage costs nothing and avoids a redesign later if the building adds secured areas.

What Goes Wrong Without One

Keys accumulate with no register. Departing residents, former cleaners and previous contractors retain working keys. A single lost common area key means either rekeying everything or accepting the risk. Contractors hold keys that open far more than their work requires. And the owners corporation has no way of demonstrating, if challenged, that reasonable access control was in place.

Frequently Asked Questions

  • Can the building master open individual apartments?

    It should not, and in a well designed system it does not. Common property access and private lot access are deliberately separated. Owners corporation rights relate to common property, and residents are entitled to expect their own lot is not on the building master.

  • Who pays for a strata master key system?

    Common property locks are normally an owners corporation expense funded through the administrative or capital works fund. Individual lot cylinders are usually the lot owner's responsibility. The specific split depends on the building's own rules and should be confirmed with the strata manager.

  • What happens when a resident loses their key?

    On a restricted system a replacement is cut by the authorised locksmith after verifying entitlement, and it is recorded. Whether the common area cylinders also need rekeying depends on whether the lost key could be linked to the building, which is a judgement the committee makes with the locksmith.

  • Can an existing building be converted to a master key system?

    Usually yes. Where the existing lock bodies accept standard cylinder formats, cylinders can be replaced without changing door hardware. A locksmith can survey the building and confirm which doors need full lockset replacement and which need cylinders only.

  • How long does installation take across a whole building?

    Design takes days rather than weeks. Installation runs at roughly fifteen to thirty minutes per cylinder, scheduled around access to common areas and individual lots. A thirty lot building is typically several days of on site work.

Contact True Locksmith on 0421-767-767 for strata and master key system design across Bayside Melbourne. Neale works with owners corporations, strata managers and building managers on hierarchy design, restricted profiles and key register setup. Over 30 years of experience. MLAA member and VIC Police registered. Serving Sandringham, Brighton, Brighton East, North Brighton, Beaumaris, Bentleigh, Black Rock, Caulfield, Cheltenham, Hampton, Highett, McKinnon, Mentone, Moorabbin, Mordialloc and Parkdale.