Even though crews worked throughout the night to help shore up the exterior wall of a building on 7 Street S.W. in downtown Calgary, witnesses nearby reported hearing a loud noise and spotted more bricks falling to the pavement below.

6 Avenue between 6 and 7 Street S.W. was closed through the night after people in the area spotted bricks falling from the exterior wall to the parking lot below.

Eyewitnesses first started reporting the issue at 608 7 Street S.W. at about 11:30 a.m. on Tuesday.

Emergency crews evacuated the building soon afterward, forcing about 150 people out of their offices.

They say there is visible damage and bulging on the east side of the building and a perimeter has been set up to keep people back.

Shortly after 11 a.m. on Wednesday, a loud bang was heard from the compromised wall and several more bricks tumbled to the pavement below.

The closure of 6 Avenue, which was lifted just before the morning commute, has been since been reinstated for the public's safety.

The Calgary Fire Department says barriers have been put in place to protect the area in case the wall completely buckles.

“There are six floors worth of brick façade there, so there’s a lot of weight there. So the collapse zone for us is a concern – what kind of area with that brick will be strewn across. So, for us, we are trying to protect that area, so that if it does collapse and it all falls at one time, the debris will be contained within a specific area which we have dictated by putting up these barriers,” says Battalion Chief John Cherweniuk.

Wayne Brown, Acting Chief Building Official says that crews are remaining on the site and has uncovered an issue with the bricks on the third and fourth floors. He says the wall is not being laterally supported and are bowing outwards.

“We’re taking every precaution at this point to ensure public safety, and we appreciate the patience of Calgarians impacted directly or indirectly. At this point, it’s impossible to predict with any certainty what might happen next with building façade, we’re simply not taking any chances,” said Brown.

Crews have spoken with the owner of the building and told them to consult an engineering firm to assess the structure of the building.

A report is expected in a few days.

For the time being, officials say that the building is closed to occupants and will not open until crews are satisfied that it is safe to enter.