A school in north county Dublin has been forced to close down a section of its building with immediate effect, after significant structural issues were discovered in the fabric of the building on Friday.
Ardgillan Community College in Balbriggan is one of 31 schools where fire safety audits were being carried out, following the discovery of serious fire safety breaches in the construction of six other schools.
All of the schools in question were built in recent years by construction company Western Building Systems.
The school has asked around 100 Transition Year students to stay at home next week.
Temporary accommodation is being organised for an additional 200 students who are also affected.
Engineers inspecting the building on Friday opened up sections of walls in two classrooms and discovered what they say are "significant structural issues".
In a statement, Dublin and Dún Laoghaire Education and Training Board, which is patron of Ardgillan Community School, said that more opening up of walls is now required.
It said that in the interests of the health and safety of students and staff, DDLETB, in consultation with the Department of Education and school management, has made the decision to close phase 1 of the school building, effective immediately.
Eighteen classrooms at the 910 pupil school are affected.
The school said arrangements to accommodate students will be communicated to parents once finalised.
The Department of Education has said that it is "working closely with the ETB in dealing with the issues".
Phase 1 of the school was built in 2009 by Western Building Systems operating under contract from the Department of Education.
The company delivered buildings under a so-called 'Rapid Build' modular model. Additional accommodation was added to Ardgillan in 2015, but that section is not affected by Friday’s discovery.
Dublin and Dún Laoghaire ETB said that fire safety assessments carried out at the school discovered flaws. It was in the course of work being undertaken to remedy these flaws that the additional problems, of a structural nature, were discovered.
The Department of Education ordered fire safety audits at Ardgillan and 30 other schools just over a year ago, after breaches were discovered in six other buildings constructed by Western Building Systems.
Announcing the audits, then education minister Richard Bruton said he believed the buildings were all of the highest standard and the audits were being carried out to be "doubly sure".
In September of last year, Mr Bruton confirmed that Western Building Systems was still eligible to apply for Government building contracts, despite the fact that it had signed off on the six buildings where fire safety breaches had been found.
There was disagreement at the time between the department and Western Building Systems as to responsibility for the failings.
Western Building Systems claimed that the Department of Education would have inspected the work and itself issued "a final, substantial completion certificate".
In a statement issued at the time it said all built schools went through a process of inspection prior to handover, conducted by departmental representatives, and that following this process those representatives issued a certificate.
The company said it believed all of its school buildings met all relevant fire safety and building regulations that prevailed at the time of handover.
But the department has maintained that the contractor was responsible for applying for and securing the Fire Certificate for the buildings, and for certifying that the building was constructed in accordance with the fire safety regulations.