This is an old, derelict industrial building that once housed workshops serving the people of Concord.
The building is derelict, with the floors mostly collapsed. The staircase connects what remains of them. An intact office with a safe is on the top floor, together with a rooftop exit, while the floor below can be dropped onto through a hole and has a small duffel bag and chem cooler.
The workhouse appears only in Fallout 4.