Burlington’s teachers and its school board reached a tentative agreement on a new contract Wednesday night, the eve of a planned strike.

The details of the agreement were not immediately disclosed. Ira Lobel, a federal mediator who led the daylong negotiating effort that stretched into the evening hours, announced to waiting reporters Wednesday night that the agreement had been signed.

Shortly after that, the head of the Burlington teachers’ union issued a statement saying everyone would benefit from the deal. 

“I am pleased to tell Burlington students, parents and residents that school will begin on time tomorrow morning,” said Fran Brock, a Burlington High School history teacher who serves as the president of the Burlington Education Association. “I know this has been a hard road, but we’re pleased to have reached an agreement with the school board.”

Terms of the agreement won’t be made public until it is ratified by both parties.

“This is terrific news for Burlington’s students,” Brock said. “In the end, the board shares the same deep devotion to the city’s children as we do, and our teams were able to reach an agreement that will allow us all to devote ourselves to making our schools even better for all of our students.”

All day Wednesday, the two sides — in separate rooms — kept up discussions, through Lobel, at the district’s headquarters.

The conflict over pay and benefits had lasted more than a year. In September, the school board imposed employment terms that gave teachers an average raise of around 2.75 percent but cut certain perks and increased teachers’ share of health insurance costs.

Teachers subsequently picketed. They voted to authorize a strike starting Thursday, pending the outcome of the final attempts at mediation.