After seven months and 18 rounds of cantankerous contract talks, Los Angeles Unified administrators and leaders of the district’s 35,000-member teachers union finally found common ground Wednesday when United Teachers Los Angeles made its first legally required step toward a strike.

The so-called “impasse” was declared by UTLA, after negotiators emerged from talks Wednesday divided by more than $800 million per year, including 3.5 percentage points in pay raises and roughly $500 million in funding for additional teachers to reduce class sizes.

In a statement titled “LAUSD Agrees With UTLA’s Declaration of Impasse,” Superintendent Ramon Cortines welcomed the legal action as a chance to reach an agreement in front of a mediator.

“I’ve been disappointed and frustrated by the lack of progress toward an agreement,” Cortines said. “It’s my hope that the appointment of a mediator will lead to an expeditious settlement that ultimately supports our students and the district at large.”

A mediator will be called in if California’s top labor authority, the Public Employment Relations Board, agrees with UTLA’s case for an impasse. Should a mediator fail to resolve the conflict, a fact-finding panel will be formed with one UTLA representative, one LAUSD representative and one neutral party. While the panel will recommend settlement terms, neither side is bound by those recommendations.

“UTLA will not accept a piecemeal agreement that addresses only one or two issues, which fails to improve student learning conditions and educator working conditions,” UTLA stated. “We will continue our aggressive organizing campaign through every stage of this process.”

UTLA’s campaign includes a $3-million “strike fund,” which will fund efforts to organize teachers for the first work stoppage and school shutdown since 1989. After regional rallies that drew several thousand teachers last year and school picket lines earlier this month, UTLA’s capacity to strike will face its greatest hurdle Feb. 26 when union leadership plans to assemble “tens of thousands” of teachers in Grand Park for a “massive rally.”

Earlier this month, the district increased its offer by one percentage point to an immediate salary hike of 5 percent, including more than seven months of back pay. LAUSD would also increase the starting salary of freshman teachers to $50,000 and fund $26 million in class size reductions.

The teachers union, however, is holding firm in its demands for an immediate 8.5 percent raise and 5,000 additional educators to reduce class sizes at an estimated budget cost of about $525 million.

Another issue raised by union leadership in its statement declaring impasse is a controversial new system for evaluating teachers. In December, an administrative judge tentatively ruled that LAUSD must repeal a crucial element of the evaluation system, which sets standards for the observation of teachers. District lawyers this week appealed that ruling to the Public Employment Relations Board, arguing a “constitutional crisis” caused by the district’s inability to effectively educate students should allow the evaluation system to stand without the consent of union leadership.

Board member Monica Garcia said she expects the impasse and involvement of state officials will move the process toward “a solution that will benefit our children.”

“I am disappointed that our teachers and health and human services professionals will not receive the 5 percent pay increase offered by our district, because it was rejected by their representatives,” Garcia said in a written statement. “However, I have confidence in Superintendent Cortines and our senior leadership to represent our collective interests.”