Lock Replacement in Ann Arbor, MI

Old doors, new locks

Michigan's housing skews old: Census Bureau estimates for 2024 put 35.6 percent of the state's homes in buildings from before 1960, and only 17.5 percent from 2000 or later. Ann Arbor's oldest neighborhoods are older still. The Old Fourth Ward, mainly northeast of downtown, has more than 400 resources, nearly a third of them built before 1900, and the Division Street district, the city's first, includes Greek Revival houses such as the Kempf House.

Doors of that age may carry a mortise lock, set into a pocket cut in the door edge, rather than the holes bored for a modern deadbolt. A new lock has to match the existing bore, backset and edge cutout, or the door has to be cut or filled to take it, which can weaken old or thin wood. Photos of the door edge help settle the choice before anything is ordered.

Replace or repair in a historic district

The Historic District Commission's design guidelines favor keeping and repairing original doors, hardware and trim. They list a new screen, storm or security door that is not full view, or that has ornamentation, as not appropriate. On an original door, lock repair or a new cylinder in the old lock case may be the better route, and it is worth asking the commission whether the work needs a permit.

Worn hardware in rentals and newer homes

Away from the historic districts, replacement is usually about wear: a deadbolt that no longer extends fully, a knob that spins, a latch that sticks. It is also a moment to look at the rest of the door. For a rental, the city's rental pre-inspection checklist lists a peephole on the main unit entry door unless the door has a window or sidelight (Section 8:503). This is general information, not legal advice.

For a lock replacement request, send:

• Photos of the door edge and both faces of the lock.
• The door's thickness and whether it is original to the house.
• Whether the property is in a historic district or rented.