A building in southwest Calgary that has been crumbling since last week is now being taken down in a painstaking process that's expected to last for weeks.

A team of workers began demolishing the broken wall, which has been falling apart since May 20, on Tuesday morning.

As soon as the problem was detected, crews blocked off the area and set up barriers and sea cans to keep people out of the danger zone.

Since then, a hole about six metres high and four metres wide has appeared, and several bricks have fallen down into the parking lot below, crushing at least one vehicle.

Mario Civitarese, the chief building official and manager with the City of Calgary Building Regulations says the wall has sustained too much damage and must be taken down.

"So the mitigation measures that are being undertaken right now involve a controlled demolition of that east facade to a point that it is fully removed, so the public is not facing any danger at this time," he said on Monday.

He says crews will work from the top down and will take apart the wall brick by brick..

Civitarese says it is still unclear what caused the problem.