Master keying a multi-tenant office building means one key system where each tenant opens only their own suite, everyone opens the shared doors, and management opens everything. Done right, a tenant moving out costs you one suite rekey, not a building-wide lock change. Here is how we set it up for property managers in San Francisco.
How a master key system works
Every cylinder in a master key system has two sets of pin positions that line up: one for its own key and one for the keys above it. That lets a single cylinder open with an employee’s key, the tenant’s sub-master and the building master. The keying chart records which key opens which door, and it is the most important document in the system.
The key levels in a multi-tenant building
| Level | Who holds it | What it opens |
|---|---|---|
| Grand master | Owner or property manager | Every door in the building |
| Master | Maintenance, janitorial, engineering | Common areas, utility and mechanical rooms, all suites if you choose |
| Tenant sub-master | Each tenant’s office manager | Every door inside that tenant’s suite |
| Change key | Individual employees | Their own office plus the suite entry |
| Common-area access | Built into every tenant key | Lobby, restrooms, mail room, bike room |
The rule that matters most: no tenant key ever opens another tenant’s suite.
Shared common areas
Lobbies, restrooms, mail rooms and bike rooms need to open for every tenant without giving anyone access to a neighbor. We key those cylinders so every tenant sub-master and change key opens them, while suite cylinders stay unique. If a common door sees heavy traffic, pairing it with a keypad or card reader on the main entrance cuts down on how many keys are floating around.
Adding new doors to an existing master key system
Yes, you can add doors without replacing the system. We read your keying chart, pin the new cylinders to fit the existing grand master and the right sub-master, and add them to the chart. If the chart is lost, we can decode an existing cylinder, but on older systems it is sometimes cleaner to re-plan one floor. Rekeying a single door within an existing system takes about 15 to 20 minutes.
When a tenant moves out
- Collect every key the tenant was issued, per the key log.
- Rekey only that suite’s cylinders to a new sub-master.
- Leave common-area cylinders alone unless keys are missing.
- Update the keying chart and issue new keys to the next tenant.
This is the main cost saving of a good system: one suite, not the whole building.
Restricted keyways: stop unauthorized copies
A restricted keyway is a patented key profile that hardware stores cannot copy. Duplicates must be ordered through the locksmith who holds the key records. In a multi-tenant building this is what keeps the system secure over years of turnover. Without it, any tenant can copy a key for a departed employee, a contractor or a friend.
Master keys plus access control
For buildings with frequent turnover or a busy front door, we often pair the master key system with access control on the main entrance and parking. Lost cards are turned off in seconds, and the mechanical master key system still covers suites, utility rooms and emergencies. Access control and security door work runs $300 to $1,200 depending on door count and hardware.
What it costs
Master key system setup in San Francisco runs $100 to $600 depending on door count, cylinder types and whether we re-pin existing locks or install new cylinders. Rekeying runs $55 to $95 per lock, plus a $29 service call. Larger buildings get an itemized quote after a walk-through.
Common mistakes we fix
- No keying chart, or a chart only the previous locksmith had
- Too many masters handed out, so the grand master is effectively public
- Standard keyways that anyone can copy at a hardware store
- Common-area doors keyed to one tenant by accident
- Rekeying the whole building when one tenant leaves
FAQ
How does a master key system work in an office building?
Each cylinder is pinned to open with its own key and the keys above it in the hierarchy. Employees open their office, tenants open their suite, and management opens every door with the grand master.
Can you add new doors to an existing master key hierarchy?
Yes. A locksmith pins the new cylinders to the existing grand master and sub-master keys and adds them to the keying chart, without replacing the rest of the system.
Do tenants need to rekey when an employee leaves?
Only if keys are not returned. With a restricted keyway, missing keys cannot be copied, so many buildings rekey just the affected office.
Who should hold the keying chart?
The owner or property manager, stored securely, with a copy held by the locksmith. Never a single tenant.
Do you work with property managers on an account?
Yes. We set up commercial accounts so rekeys, new doors and emergency calls are scheduled and billed to the building.
Talk to a commercial locksmith
Managing a multi-tenant building in San Francisco? Our commercial locksmith team will walk the building and draw up a keying plan. Call (415) 205-5718. We usually arrive in 15 to 20 minutes for urgent calls.