Teachers in Alberta's public, Catholic and Francophone schools have rejected a mediator's proposal that would have given them an average wage increase of 15 per cent over four years.

The offer didn't go far enough to address teachers' concerns about crowded classrooms, packed with a growing numbers of students who have complex and differing needs, said Alberta Teachers' Association (ATA) president Jason Schilling.

"Teachers are feeling burned out and frustrated, and they wanted to see more," Schi…