The fire at 225 Humphrey St., which is still under investigation, was called in at 1:03 a.m. and firefighters had the blaze extinguished five hours later, according to Swampscott Fire Lt. Jeff Marsh.
"When firefighters arrived on the scene, there was a heavy volume of fire showing on the second and third floors," Marsh said.
Marsh said the building sustained "severe damage," but he did not have a dollar estimate.
"The building was under construction. The fire was heaviest on the second and third floors. There was heavy damage on the third floor, moderate damage on the second floor and minimal damage on the first floor," Marsh said.
There were no injuries and none of the neighboring buildings were damaged, according to Marsh, who said firefighters " did a great job stopping the fire from spreading to adjacent buildings."
On Thursday morning, firefighters, Swampscott Police Detective Ted Delano and investigators from the state Fire Marshall's Office were at the scene looking for hot spots and trying to determine the cause of the blaze.
The building, a condominium complex that was under construction, is owned by 225 Humphrey Street LLC, which has a mailing address in care of Hirsch Construction of Salem, according to the assessor's office. Calls to Hirsch Construction were not immediately returned.
