Pupils at a Comber primary school had to be sent home early on Friday after inspectors warned that the school's roof was in a dangerous condition.
Andrews Memorial Primary School in the Co Down town told children's parents on Friday evening that a large part of the school would be closed this week while emergency repairs are carried out.
Parents are now faced with having to find a way to look after their children who cannot attend the school while the repairs are carried out.
One angry mum contacted the Belfast Telegraph to complain about how the closure would hit her and her family in the run up to Christmas.
"I feel sick to my stomach. It's horrific," she said.
"You find out on a Friday night that your child has no school to go to for three days.
"If I don't go to work, I don't get paid.
"If I pay my child minder extra, that's my wages - and it's three or four weeks to Christmas."
In an email to parents, principal Ralph Magee wrote: "This is an emergency; it is a case of crisis management.
"We need everyone to remain calm and patient while those responsible for fixing the problems are given time to do precisely that.
"I'm afraid there will be significant disruption to the school timetable."
He said the school had to send three classes of children home on Friday because of a problem with the roof of the school's upstairs classrooms
"Fortunately, everyone was and is safe," he wrote.
The email also told pupils' parents that maintenance officers from the Education Authority (EA) had been at the school on Friday - and that a new roof was needed on the part of the school used by P3, P4, P5 and P6 children.
Children in P1, P2 and P7 at the school are unaffected by the disruption, the principal said.
"At this stage, we cannot determine how long the job will take, but in the interim we cannot use any of these classrooms," Mr Magee wrote.
"That decision has been made at Directorate level within the Education Authority."
It's understood that the primary school is planning to install temporary classroom accommodation while the remedial works to the roof are under way.
The principal promised to communicate his plan for coping with the crisis on Tuesday.
Andrews Memorial School could not be reached for comment yesterday.
A spokeswoman for the Education Authority said last night that it would respond today, once it had received the engineer's report into the school building.