The Charlotte-Mecklenburg school board unanimously approved year-round calendars for four schools Tuesday, launching plans to start their 2013-14 school year in July.

“The work starts now,” Denise Watts, Project LIFT zone superintendent, said in an interview. “This is a lifestyle change for teachers. This is a lifestyle change for families.”

The year-round calendars affect four preK-8 schools that are part of Project LIFT (for Leadership and Investment for Transformation), a public-private partnership to boost achievement at West Charlotte High and its eight feeder schools. Donors have pledged $55 million over the next five years; that will cover the $2.1 million cost of adding 19 school days at Druid Hills and Thomasboro.