A fire at a building under construction in the city’s Beltline that sent huge clouds of black smoke into the sky on Saturday afternoon is finally out.

The four-storey residential building on Centre Street and 17th Avenue South was just months away from completion when it caught fire just before noon.

Calgary fire investigators are still trying to determine what ignited the exposed wooden frame.

The building, owned by Torode Realty will have to be completely demolished.

On Sunday, fire crews dismantled the top part of building so aerial crews could hit hard to reach hot spots with the hoses.

Control of the building has now been passed to the city's safety code officers who will oversee its demolition in conjunction with the owner and its insurance company.

The eastbound lane of 17th Avenue between Centre Street South and 1 Street SE remains closed but crews have setup a two-way traffic route in the westbound lanes.

The southbound lane of Centre Street South between 17th and 18th Avenues is also closed.

The closures will remain in place until further notice and motorists are advised to expect delays and to use alternate routes.

Investigators are asking anyone with images of the fire to email them to Brad.McDonald@calgary.ca.