The vandals struck last night – a day before the school was due to close today for the summer holidays.
The vandals also stole a number of laptop computers and other items from the well-known school in Murlog.
The also wrecked filing cabins and caused a considerable amount of general damage throughout the school.
A source at the school, which counts soccer star Shay Given amongst its past pupils, said the pupils and the parents of the school are hugely upset by the break-in.
“What sort of sick people target and destroy a children’s school? The place was absolutely wrecked.
“As disgraceful as it is in stealing computers, they did not have to cause the damage they did.
“The school have tried to clean the mess up as best they can because they didn’t want the children to see the mess,” he said.
The attack comes in the wake of a recent meeting organised by locals concerned about vandalism attacks in the area.
A local Church of Ireland building, St Lugadius’, has been attacked on at least three occasions.