The more asbestos that workers remove from St. Augustine Cathedral’s parish hall, the closer the 100-year-old building gets to demolition.

The three-week process to remove a coating with asbestos from the walls of the building kicks off Phase 2 of the Roman Catholic Diocese of Tucson’s Cathedral Square project downtown.

The Tucson City Council approved the demolition of the building in June. Once the building on West Ochoa Street has been prepared to come down, the actual process will take another four to six weeks, said John Shaheen, the director of insurance and property for the diocese.

If the project moves forward without complications, Shaheen expects to see demolition complete and the area cleared by Dec. 1.

A four-story office complex and events center will replace the hall, which is not even large enough to serve the families at the cathedral parish, much less the rest of the diocese, Bishop Gerald Kicanas told the Star in January.

The new complex is projected to open in April 2019, Shaheen said.

The upcoming demolition of the parish hall comes as the restoration of Our Lady’s Chapel next-door nears completion. The diocese will host an open house at the chapel on West Ochoa Street from 9 a.m. to 2 p.m. Sunday, Sept. 25.

The development project plans also include the eventual demolition of the diocese’s current office building at 111 S. Church Ave. Those offices will be vacated in October.

As part of the renovation, historic Marist College will be preserved, as the Foundation for Senior Living transforms both that property and the former diocese offices into a community center and senior living apartments.

Contact reporter Johanna Willett at jwillett@tucson.com or 573-4357. On Twitter: @JohannaWillett