Nearby residents said they heard a loud bang and then saw smoke coming from Allied Concrete Cutters and Drillers.
Residents also reported seeing 12 fire trucks on the scene.
Senior Station Officer Jim Maclean said they received a call at 8:54pm from The Bike Maintenance Shop reporting smoke coming from the building.
"Flames were showing from inside and from top of the roof, so we broke in and took hoses."
Maclean said it they are not treating it as suspicious, and that the main part of the fire appeared to be coming from a trailer in the parking area of the building.
"There's some other structural damage but that hasn't been fully ascertained."
He said he was not sure what had caused the fire, and 12 trucks with 30 firefighters had responded to the initial call.
A number were sent away "quite quickly" once they arrived, Maclean said.
"The fire has been contained to the left hand main parking working space of building and appears not to have spread to the office or administration areas... we consider that a good result."
The owners of the business are at the scene, and fire crews are now working to forcibly open a roller door in the building to better assess the damage.
Ezra Connolly, who lives across the street from the address, was one of the first at the scene at around 9.50pm.
He said he saw the blaze when he was taking his bins out.
Connolly estimated the flames to have been 2.5m wide and 1.5m above the roof at its tallest and there was "heaps of smoke".
Fire fighters broken down the door to access the building, he said.
