Updated: 10/27/10 9:51 p.m.

CHICAGO (CBS) – A 43-day sit-in at Whitter Elementary School’s field house over a makeshift library has officially ended Wednesday evening.

LISTEN: Newsradio 780’s David Roe Reports

Parents who staged a sit-in since Sept. 15 over a much-debated library issue walked out of the field house about 7:30 p.m.

Chicago Public Schools CEO Ron Huberman agreed earlier Wednesday to give parents at Whittier Elementary a signed letter committing to a deal to put a library at Whittier.

Last week, Huberman said the district would install a library at the school and cancel plans to demolish the field house, where parents have set up a temporary library.

Parents showed up at Wednesday’s school board meeting to demand a commitment in writing from Huberman and board members.

Board of Education President Mary Richardson-Lowry said the board could not make any commitment in writing until Huberman and Whittier parents finalize their agreement. Huberman agreed to sign a letter setting their agreement in writing.

The letter was delivered to Whittier parents at CPS headquarters at 125 S. Clark St. around 5 p.m. Wednesday. Parents initially said they like much of what’s in the letter, but they said its contents were not specific enough about the library and they planned to continue a sit-in at least until their next meeting with Huberman at 9:30 a.m. on Friday.

But in a turn of events, parents walked out of the field house and ended the sit-in Wednesday evening.

Lisa Angonese has two children at Whittier, and she’s been backing the effort since day one.

“We all grew close to the building. There is a history to the building, it’s been here a long time,” said Angonese. “And the children are used to coming to the building.”

Many, like Rozalinda Borcila don’t have students at Whittier. They are simply activists.

“I’m a cultural person, I’m a former teacher myself,” said Borcila. “And so I was really inspired to become involved and to do whatever I could in support.”

Huberman is set to meet with the parents on Friday to work out the details of where the library would be placed. The library’s location could become a major sticking point, however.

The district wants to build a library inside the existing school building, but Whittier parents have said there’s not enough room without losing other facilities they need. And CPS has said that the field house is not an option for a permanent library.

CPS spokeswoman Monique Bond also said that the district cannot justify expanding the main school building because the school is at 75 percent enrollment and a school needs to be overcrowded before CPS can expand.

Parents have staged a sit-in at the field house since Sept. 15, demanding that CPS cancel plans to tear it down to build a soccer field. They want the district to build a library at the field house, but CPS has said the building is not safe.

Whittier Parent Araceli Gonzalez said Wednesday as the supporters filed out: “We are not abandoning the field house, nor we ending our fight.”

Huberman said he has already sent the group two signed letters agreeing not to tear down the field house.

School officials will take a month to determine whether it’s feasible to renovate the old building – named La Casita by the parents – while looking for space in the main school building for a library.

Huberman said tax-increment financing money can pay for the library.

CBS 2’s Pamela Jones contributed to this report.