They see it in their school communities; they despair at its ramifications. And how easily homelessness can hit a family. So they want to help make a difference by sleeping rough on Thursday.

Mount Carmel School principal Michael Green, whose school is in Yass, is taking part in his third Vinnies CEO Sleepout, saying homelessness is not only an urban problem.

"I've personally witnessed some of the trauma that is caused to families who are displaced from their homes because of complicated reasons around family violence or addiction or mental health," Mr Green said.

"So, out in Yass we don't see many people sleeping rough, but we do know of families who are couch surfing or relying on hotel accommodation or sleeping in their car. So it's a problem right across the nation."

Ross Fox, director of Catholic Education for the Archdiocese of Canberra and Goulburn, on Friday was joined by four principals doing the sleepout - Mr Green from Yass, Good Shepherd Primary School principal David Austin (Amaroo), St John Paul II College principal Catherine Rey (Nicholls) and St Thomas Aquinas Primary School principal Leah Taylor (West Belconnen).

St Francis Xavier College principal Paul Carroll is in isolation but continuing to fundraise while assistant principal Dearne Bassett will join the sleepout.

Other principals are sleeping out at their school, with students also participating. Catherine Rey said staff and students at St John Paul II College had raised $72,000 over nearly a decade, about to complete their ninth sleepout.

"Homelessness is something we can hardly contemplate and the more you find out about it, you find people, through no fault of their own, kids like our kids at school, can find themselves homeless, and it's frightening," Ms Rey said. "So any awareness we can raise, any funds, is crucial."

ACT business, community and government leaders in last year's sleepout raised more than $1 million dollars for Vinnies' homelessness and social impact services.

Mr Austin will be doing his fifth sleepout. He also a leader for the Vinnies Night Patrol, which hands out clothes, food and other essentials across Canberra and Queanbeyan.

"So I see first hand where the winter woollies go, where the fundraising goes. It's two vans 364 nights a year," he said.

St Clare's College in Griffith is planning to do a sleepout at the school next term, college captain Sarah Mooney ready to participate.

"I think coming from a very privileged school, it's really good when we have the capacity to raise awareness and get involved," she said.

Mr Fox was proud so many schools and principals were taking part. "We're very clear on our commitment to social justice and it's really motivated by a Christian understanding of the importance of every individual, and so our schools are true to that,' he said.

And Michael Green, from Mount Carmel School, said the children wanted to be involved. "They love an opportunity to do something affirmative and to participate, rather than just sit back and talk about it," he said.