Fire crews were called to the house near Marquette Crescent and Champlain Street at 1 p.m.
Vancouver fire battalion chief Peter Bridge said the "stubborn" fire started on the roof.
"It got up into the attic spaces where there are staggered roofs. The fire was crawling its way down the attics," he said. "We had to pull a lot of walls down, we had to change personnel very fast. The heat inside and the heat outside is really hard on our systems."
Bridge said there were no injuries and that it appears most of the residents were able to evacuate on their own.
Enoch Tee, who lives in the building, says he first saw smoke on the patio, but the fire suddenly escalated after that.
"When the flames started erupting, it was coming in the windows and coming through the walls," he said. "So it was definitely inside and the flames went up about five feet high from the roof, pretty large flames."
It's not yet known whether anyone was inside the unit when the blaze broke out. Investigators are still looking into the cause of the fire.