The Lawrence school district and its teachers union will meet with a mediator in July after failing to agree on the size of raises for teachers Wednesday.

Both sides moved closer on the salary issue throughout the nearly five-hour negotiating session and came to agreement on the other parts of the contract. At the end of the evening, however, they were still $500 apart on the size of raises for teachers.

Teachers are paid based on a pay schedule that provides more money both for teachers with more education and for teachers with more years of service, up to a maximum amount.

Both the district and the union offered plans that would allow teachers to move to new levels on the pay schedule. The district’s offer was to increase each level on the schedule by $1,000, and the union countered with an offer to increase each level by $1,500.

Kyle Hayden, the district’s chief operations officer, said the district’s salary offer would put an additional $1.42 million into the salary pool, about 3.5 percent higher than the previous year.

“I think we’ve given what we have to give,” said Bob Byers, a school board member.

The district and the teachers union agreed on Wednesday on a range of other issues. They agreed to keeping the existing contract language on issues like plan time and the duty day, and agreed to implement a new method of evaluating teachers.

But a sticking point in the negotiations involved a one-time $1,000 payment given to teachers last year.

Byers reiterated his belief that one-time payments were not meant to carry over into the next year’s salary calculations.

David Reber, the union’s lead negotiator and a science teacher at Free State High School, said that half of the teachers in the district had already reached the maximum amounts on the pay schedule for years of service. For those people, he said, their salaries would be the same as they were last year.

“I think people are going to look at that and say, ‘I’m not getting any more,'” Reber said. “We’re going to have half the people upset.”

Hayden said that in the end the union’s last offer was still 50 percent higher than the district’s last offer.

“It’s still a significant chunk of money,” Hayden said. “And it’s well beyond what I have the authority to give.”

After the meeting, Reber said that year after year other districts in the state get better raises than in Lawrence.

“Lawrence isn’t unique in their budget woes compared to everywhere else,” he said.