Firefighters were called to a building housing Adairs and Adrenaline boxing gym on Swift Street on Sunday night.

About 13mm of rain fell in a 14-minute period from 11.46pm, with a large amount of water flooding into the roof of the businesses.

Stock inside the homeware retailer appeared to have been damaged.

Adrenaline owner Kade Brown arrived for work at 5.15am and found roof tiles were starting to cave in at his gym.

Water had flowed into a section of the building converted in June to run classes. 

Mr Brown said the gym was only running boxing classes on Monday, which were held in a different area, but said it would be “hard work” to get things fixed by Tuesday.

Water poured from the roof as maintenance worker Ben Sellwood removed damaged sections.

Mr Brown said he had managed to continue with planned classes.

“Our roof has been impacted fairly well,” he said.

“All the rest of it, given the nature of our business, we’ve probably been fairly lucky.

“I think next door (Adairs) has been impacted a hell of a lot more than we have.”

Mr Brown said most damage was to the building.

“All of our equipment seems to be pretty good,” he said.

“We’ve got a fair bit of water over the equipment, but it’s all working. It could have been a hell of a lot worse.”

“We’ll do our best to get back up and running.”

Firefighter Simon Huggett said alarms in the Adairs roof had alerted brigades to the damage.

Water ran into lights, leading to concerns about the risk of fire.

Firefighters had to push water out of the building, which was hampered by the fact rain continued to fall through the roof and into the store. 

“It ran through the roof, went through the fire alarm system and went into the lights,” Mr Huggett said. 

“The boys just shut off the fire alarm system in the zones where the water was coming through. 

“Because it was running through the lights, it was possible it could start a fire, so they found the fuse box and turned off the power.” 

Adairs remained closed past its normal 9am opening time.

Workers from different trades attended the building on Monday morning to fix the damage. 

Victorian SES spokeswoman Bridie Walsh said the storm caused few problems in the North East. 

Volunteers were only called to six minor jobs, including fallen trees and building damage. 

“It didn’t generate any major incidents,” she said.

“We are encouraging everyone to prepare before storms by tying down or packing any loose items in your backyard or balcony.”

Albury SES spokesman Tim Keown said it was the busy time of year for thunderstorms. 

“People should be aware that thunderstorms like that can occur between now and February,” he said. 

“People should try to prepare their properties where they can.”