By Audrina Bigos

CHICAGO (CBS) — In just one week, Chicago public school teachers could be walking the picket line.

The looming strike date: October 17.

CBS 2’s Audrina Bigos has more about why there’s still no deal.

And after listening to both sides today, it doesn’t seem like they’re any closer to making a deal than they were a week ago. Apparently the latest hold up is something we haven’t hear much about publicly: The issue of affordable housing.

In 2012, a teacher’s strike lasted seven school days. In 2016, there was a one day strike.

Now, another strike is looming.

There have been 49 bargaining meetings between negotiators with the Chicago Teacher’s Union and Chicago Public Schools. 144 days of talks with no agreement.

“We need them to come back to the table,” said Chicago Mayor Lori Lightfoot.

On Thursday, Lightfoot said the CTU is holding up contract talks.

“We can’t bargain alone. We have to have them come to the table in a constructive way with a written, comprehensive counter proposal,” she added.

The union said it’s been clear about its demands.

“A contract for basic services in our schools like a nurse in every school, every day. Social workers, special educators. Case managers,” said CTU president Jesse Sharkey.

CTU wants the additional staffing written into a new contract. CPS said that’s covered with 10 million dollars budgeted for 95 new employees in 2020.

Then there’s the pay issue.

Teachers want a 15% pay raise over three years. The city is offering teachers a 16% raise over five years. Teachers also want smaller class sizes, claiming some have as many as 40 students.

But CPS argued policies are already in place with limits of 28 students per classrooms in elementary school, and 31 in middle and high school.

“We have made some progress on some issues but not in the core set of issues, on compensation, benefits, insurance, staffing,” Lightfoot said.

The CTU is demanding help for nearly 17,000 students who are homeless. The union wants more staff in place to support families in danger of losing their homes. And they want a program that helps teachers buy homes.