At all four sites, the district plans to keep the middle schoolers confined to their own areas, away from older or younger students.
The district hopes by the 2015-16 school year to bring all Cedarbrook students back together in modular or temporary units on a single site.
It will likely take about four years to design and build a new permanent middle school, Thomas said.
Cedarbrook has been dealing with mold problems for a decade, and they spun out of control this summer. The school opened two weeks late in September as crews swept the building, and since then 12 classrooms and the cafeteria have had mold recurrences and are now closed.
At a meeting with parents Monday night, Superintendent Natalie Thomas said there was no more time to delay.
"There's no amount of money that will prevent this from happening again in the spring or sooner," Thomas said, noting that the leaky roof is already loaded with snow.
The district's faculty and staff were notified of the plan Monday afternoon. Thomas and Cedarbrook principal Iris Parker hosted meetings Monday night with parents, reporters, and community members.
The students were to be notified Tuesday morning, but many found out much earlier. Parker said there would be counselors on hand to talk to any students who are struggling with the change.
Some parents were angry about the split and the timeline, demanding to know why the district could not wait a few months more. "I feel like we've been shot in the gut," one woman told Thomas.
Others were resigned to a situation they say has no good solution.
"I think this is going to be very costly," said Diane Townshend, who has children at Cedarbrook and Elkins Park. "They don't have a lot of alternatives, and they don't have a lot of time."