It didn’t take a lot of effort Thursday to see why Catholic Charities and its private sector champions broke ground on the first phase of a $100 million project to replace the aging and undersized Dorothy Day Center.

As donors gathered under a large white tent in downtown St. Paul to celebrate construction of the future home of Higher Ground St. Paul, dozens of people lined up across the street at the Listening House, a program that offers housing and support at an old and cramped former dormitory for nursing students called Mary Hall.

If all goes according to plan, Tim Marx, head of Catholic Charities and his fundraising team won’t have to use the old Mary Hall for much longer.

“If fundraising continues as well as it has,” Marx told the assembled crowd at Wednesday’s groundbreaking, “this project will be complete by December 2018.”

Thursday marked a pair of milestones for the ambitious plan to replace Dorothy Day Center and other aging buildings with a new downtown campus that will include a homeless shelter, permanent housing and counseling and job services for hundreds of people.

First was the groundbreaking for Higher Ground — the five-story building that will replace the Dorothy Day Center, which has helped serve the homeless. The other was the announcement that six months after launching a campaign to raise $40 million in private funding for construction, more than half of that money — $23.7 million in private funding — has been raised and committed to the project, which will be completed in two phases.

Higher Ground is phase one, and will have an overnight shelter, a place to serve meals and 193 units of permanent housing. It will open in 2016.

The second phase, called the Opportunity Center, will help connect people with counseling, health and employment services. It will also provide another 170 units of permanent housing. The second phase will be built on the site of the current Dorothy Day Center and could be completed by the end of 2018.

The $100 million for the entire project is being raised in a public-private partnership, with the state and other public sources covering about $60 million. So far, about $25 million of that public portion has been committed — most of it coming from the state — with Gov. Mark Dayton saying Thursday that he intends to make a large bonding request to fund much of the rest.

As state and local government officials joined Thursday with area business and nonprofit leaders to celebrate their progress and push for additional giving, a group of singers made up of current and former Catholic Charities clients lifted their voices to the top of the tent.

“Over my head, I hear a voice in the air. There must be a God somewhere,” sang the Giving Voice Choral Project. “Over our heads, we all deserve a roof.”

Doug Baker Jr., CEO of Ecolab and a co-chairman of the project’s fundraising campaign, exhorted the gathered crowd to keep working to help St. Paul’s homeless.

Go out, he told those who have given, “and get others. Ultimately, that’s what’s going to make the difference.”