Calgary firefighters worked to hose down a blaze in a pub and restaurant in southeast Ramsay Sunday morning.

Crews arrived at the 1100 block of 12 Street at around 2:30 a.m. to find smoke and flames visible from the outside of the single-storey building

Thirty firefighters wrangled with the blaze — which had fully consumed the interior and spread to the roof, causing it to collapse — for two and a half hours.

While firefighters were unable to enter and search the structure, they say it’s unexpected it had any occupants at the time of the fire.

Calgary police are on the scene managing road access, and ATCO Gas is assisting with shutting off utilities.

Fire investigators are currently figuring out the cause.

As a result, drivers should be aware of closures on 12 Street and 11 Avenue throughout the day.