A fire early Thursday has caused an estimated $500,000 damage to a downtown restaurant undergoing extensive renovations.

A passing motorist noticed the fire at Respect is Burning about 2:15 a.m. and contacted Greater Sudbury Fire Services, said public safety officer Mitch Theriault.

“There wasn’t a lot of contents in the building at the time,” he said. “That’s why the fire didn’t spread that far. But the smoke spread everywhere.”

The fire caused moderate smoke damage and severe smoke damage to the restaurant. A total of 12 firefighters from two fire stations responded.

Theriault said a space heater or electrical problem is suspected as the cause of the fire. He said nearby businesses located in the same block were not affected.

Earlier this week, Downtown Sudbury announced that founders Rob and Mini Gregorini have started to re-invent Respect is Burning Supperclub.

The work began March 3 and was to include an expanded kitchen, featuring updated equipment and the development of new identities.

“The improved kitchen will be instrumental in the development of the Red Fang Tavern with its own unique food identity, as well as The Mars Hall,” the release said. “The Mars Hall will emerge as an events and show hall, which will not only be a terrific addition to the downtown, but will bring the Supperclub one step closer to the original vision behind the popular restaurant.”