Field notes · 2026-08-19 · 5 min
Master key systems for co-ops: what boards get wrong
A master system is a chart, not a pile of keys. How to set one up that survives staff turnover.
The failure mode is always the chart
Master systems don't fail because a pin wears out — they fail because nobody wrote down the hierarchy. Ten years and three supers later, nobody knows which key opens what, and the 'fix' is an expensive full re-pin that a written chart would have prevented.
Plan the hierarchy before cutting anything
Decide the levels first: super, management, per-unit. Leave expansion room in the chart for the storage room you'll add and the bike room you'll convert. A system planned for growth grows; a system improvised door-by-door collapses.
Restricted keyways are what make it real
A master system on a hardware-store keyway is a suggestion — anyone can copy any key for two dollars. Restricted keyways (Medeco, Mul-T-Lock) mean copies require documented authorization from the board. That is the difference between key control and key hope.
Written by President Locksmith & Security — a working locksmith dispatching from Park Slope, Brooklyn. Questions about your door? (646) 832-4007.