It wasn't immediately clear what caused the collapse, which occurred around 5 p.m. Wednesday in the unit block of Kansas Road in Little Egg Harbor Township.
Authorities say the workers were being treated at a hospital for injuries not considered life-threatening.
One worker suffered back, neck and foot injuries and was flown to a hospital, while two others were treated at another hospital for undisclosed injuries.
A fourth worker reportedly refused treatment at the scene.
Authorities say one of the workers apparently fell from the home's top floor.
The Associated Press contributed to this report.