Lock Replacement in Boston, MA

Replacing hardware on older doors

In the Census Bureau's 2024 American Community Survey, about 30 percent of Massachusetts homes were built in 1939 or earlier, and doors that old have often been through several generations of hardware. Some hold a mortise lock, set into a pocket cut in the door's edge. Swapping that for a modern cylindrical lock can mean altering the door, so a like-for-like mortise replacement keeps the door intact and is often the simpler option.

Historic districts: ask before changing what shows

Beacon Hill is the oldest historic district in Massachusetts, and its rules reach the front door. Chapter 616 of the Acts of 1955, as amended, bars altering exterior features open to view from a public way without a Certificate of Appropriateness from the Beacon Hill Architectural Commission, with fines of up to 1,000 dollars per day for violations. On doors, the guidelines keep original doors and hardware, duplicated in the same material and style only when beyond repair. Only paneled doors are permitted, so a flush or metal-clad replacement is out, and new hardware should replicate the original or be of an appropriate design.

Elsewhere, Back Bay, Bay Village and the South End each answer to their own district commission, and the city takes design review applications for all 10 of its historic districts. Before changing visible locks, knobs or trim on a street-facing door in any district, ask the commission.

This is general information, not legal advice.

Renters

The State Sanitary Code, 105 CMR 410.270, makes the owner responsible for keeping each unit entry door lockable and other exterior doors fitted with an operating lock, so a renter should ask the owner before replacing hardware.

What helps in a replacement request

Photos of both faces of the door and of its edge, the neighborhood, whether the building sits in a historic district, and whether commission approval is already in hand. See lock replacement, lock repair if the existing hardware is worth keeping, or the Boston page.