Firefighters spent several hours battling a three-alarm fire that broke out at a strip mall in Surrey, B.C. early Wednesday morning. 

Dark smoke was pouring out of the 80 Avenue building when crews were called to the scene at around 1 a.m.

Asst. Chief Jason Cairney said one unit of the building was already fully engulfed when firefighters arrived, and the flames spread quickly to other businesses. The fire also ignited some insulation in the roof, which made the stubborn blaze even harder to put out.

"It's hard to get at," Cairney said. "They have to do some work on the roof to cut away some of the material and then peel it back and get the water in there."

There are at least a dozen units in the building, including a flooring company, multiple restaurants and a restoration company.

Several sustained fire or water damage as firefighters worked to extinguish the flames.

Grant MacDougall, supervisor at On Side Restoration Services, said there was significant smoke and water at his work, which employs 43 people.

"We are in the restoration business, we're used to this kind of stuff," MacDougall said. "I guess it's as dramatic as it is to our clients. It's very disruptive."

Authorities haven't determined what caused the fire or where it started, but an investigator will begin examining the scene once it's deemed safe.

Thirty-nine firefighters and 11 trucks were dispatched to the fire.

With files from CTV Vancouver's Nafeesa Karim