LONDON — Not that it is unusual to see shabby old buildings being gutted by construction workers in a rapidly gentrifying area of east London like Hackney Road, but I felt a pang of regret when I spotted them starting work on one last week. I wasn’t concerned about its architecture, which is much the same as that of any of the other 19th-century terraced houses in the neighborhood, but about the signage.

“To all responsible person” is painted in big black letters on the front of the building, and a description of a locksmith and safe maker is engraved on the side wall. “John Tann’s Reliance Locks, Fire & Burglarproof, Safes, Iron Doors,” it begins. Both signs have long outlived their usefulness: like the missing “s” at the end of “person,” Tann’s workshop disappeared decades ago.

Will those signs survive the house’s renovation? I doubt it. The only reason they are still there is because the building has been neglected for so long, and was not deemed to be worth repairing or rebuilding until recently. Yet if the signs are removed, the neighborhood will be the poorer, having lost part of its character and some poignant symbols of its history....