Firefighters were called to a house blaze in Gravesend this morning after a generator reportedly blew up.

Flames spread through the three-storey building in Milton Road, which had been under refurbishment.

A team of workmen were in the property at the time of the incident, but all escaped unharmed.

VIDEO: Three-story house blaze in Gravesend

Firefighters used main jets and hose reels to tackle the blaze, which affected the roof and all three floors of the building.

The road was closed for several hours, but re-opened at about 1pm.

Luke Randall, 25, of Lignum Carpentry and Construction, was working in the property next door with his father, Andrew, when the fire broke out at just after 9.30am.

“We think a generator exploded on the bottom floor,” he said.

“I feel really sorry for them (the men working in the property). It’s a different company working on that building. They’re really nice guys and are really helpful as well.”

Incident manager Greg Theophanidis confirmed that a generator was the suspected cause of the blaze.

“The fire certainly started on the ground floor and as it’s under refurbishment at the moment it’s just straight up through the building,” he said.

“We’ve got five engines here, we’ve got a team at the back of the property and a team at the front working on putting the fire out. In total there are about 30 personnel with us.”

Police were also called to the scene to block the road off, which caused some delays in the town centre.

Eric Ward, 47, was one of those forced to curtail his journey because of the fire.

“It just randomly caught fire, and it was absolutely massive,” he said.

“I think it’s supposed to be flats eventually. It’s unbelievable the size of it.”