Seventeen schools constructed by Western Building Systems (WBS) have been assessed as having structural defects that warrant protective interim works before they can open on Monday.

They include two Portlaoise primary schools, Portlaoise Educate Together and Gaelscoil Phortlaoise.

They also include six school buildings, all in Dublin, that have already been informed of problems requiring urgent intervention.

On Wednesday, protective fencing was placed around the two schools in Portlaoise to keep pupils and staff safe in the event of any parts of the external walls falling away.

The number of schools affected may grow on Thursday because decisions have only been made in the case of 29 of the 42 schools, built by WBS. Whether emergency works are required or not in the additional 13 has yet to be decided. These are subject to ongoing structural assessment and analysis.

Engineers and Department of Education officials spent Wednesday analysing the initial reports from inspectors who carried out structural assessments of all the schools built by WBS.

Safety reviews of the schools, built by the Tyrone-based developer, began after structural issues were discovered in Ardgillan Community College, Balbriggan, more than a week ago.

The Department of Education said, of the 17 schools due to reopen on Monday, 14 schools have been cleared to open in full following external intervention in the form of a fence around the building and protective decking.

In three schools, the ground floor will be cleared to open following the implementation of internal engineering solutions and external interventions.

Minister for Education Joe McHugh said the outcomes of further structural assessments received Wednesday are important in providing clarity to school authorities, students and parents.

“The advice I have received is that no other building has presented the same severity of structural issues as those identified in Phase One of Ardgillan Community College, which was built in 2009,”said Mr McHugh.

Contractors have commenced work on site at five schools previously confirmed as requiring internal and/or external interventions.

He said the target is to have this work completed in the coming days.

In three schools that had to close over structural issues – Tyrrelstown Educate Together National School, St Luke’s National School and Gaelscoil Eiscir Riada in Lucan – department officials said alternative accommodation had been found for all classes, in other schools.

Off-site interim accommodation arrangements have now been confirmed in principle and communications will issue from the schools shortly.

Problems first emerged with schools built by WBS in October 2015, when fire safety issues were discovered at Rush-Lusk Educate Together primary school.

Last September, the department published fire-safety audits of five WBS-constructed schools, which found building work did not meet required standards.

Following the audits, the department announced further fire safety reviews would be carried out at other schools delivered by the construction firm.

Structural problems were discovered when a wall was opened for inspection during a fire safety audit in Ardgillan Community College. A structural engineer found ties fixing the exterior and interior walls were absent or inadequate in places, and were at risk of collapse during storm-force winds.

Some of the 42 schools were built by WBS under a fast track “rapid build” programme between 2007 and 2013, with some schools built within just three months.

The developer has been paid more than €80 million since 2013 by the department for school building projects.

WBS has insisted that the Department of Education signed off on each project. In a statement on Wednesday night it said it noted the latest statement from the Department of Education but said no details of the assessments have been shared with it.

“We do not know what any conclusions reached at this point are based on. So far, we have been invited to meet with the Department’s inspectors and officials at 13 of the 42 schools. We had insufficient time on site to make structural evaluations,” it said.

“What is becoming clearer is that schools previously certified for completion as being free from defects by the Department, and described less than twelve months ago by the then Minister as being built to the highest standards, are now being deemed to require remedial works,” it added.

“That such a turnaround is now being reached is troubling on a wider scale. Given the assessment process remains ongoing at this point, we are limited in what we can say. We wish to reiterate once more our recognition of the impact this has had on pupils, parents and teachers at the schools involved. While it remains unclear as to why and how we have reached this point, we are not walking away. We honour our contracts. We continue to engage with the Department and remain keen to meet the Minister.

“Hard work, innovation and high standards have underpinned our business for 35 years. The Department itself has awarded us contracts to build 42 schools over a 14 year period based on continuous quality of delivery. We are a reputable contractor who has always delivered to our contracts.”

The schools cleared to open in full, following external intervention in the form of a fence around the building and protective decking include:

Scoil Chaitlín Maude, Tallaght, Dublin

Castlemills Education Centre, Balbriggan, Dublin

Scoil Phádraig Naofa, Athy, Kildare

Athy Model School (GP Hall Extension only), Kildare

Gaelscoil Átha Í (GP Hall Extension only), Kildare

Lucan East Educate Together National School, Dublin

Convent National School, Portarlington, Laois

Scoil Phádraig Naofa, Rochestown, Cork

Gaelscoil Phortlaoise, Laois

Portlaoise Educate Together National School, Laois

St Paul’s National School, Ratoath, Meath

Coláiste De Lacy, Ashbourne, Meath

Gaelscoil na Mí, Ashbourne, Meath

Ashbourne Educate Together National School, Meath

Schools in which the ground floor will be enabled to open following the implementation of internal engineering solutions and external interventions include:

Tyrrelstown Educate Together National School, Dublin

St Luke’s National School, Tyrellstown, Dublin

Gaelscoil Eiscir Riada, Lucan, Dublin

Schools cleared to open in full, without any internal or external intervention include:

Luttrellstown Community College, Dublin

Gaelscoil Shliabh Rua, Dublin 18

Broombridge Educate Together National School, Dublin

Scoil Choilm Community National School, Porterstown, Dublin

Gaelscoil na Giúise, Firhouse, Dublin

Gaelscoil Thulach na nÓg, Dunboyne, Co Meath.

Maryborough National School, Portlaoise, Co Laois.

Scoil Aoife Community National School, Citywest, Dublin

Letterkenny Educate Together National School, Co Donegal

Firhouse Educate Together National School, Dublin

St. Joseph’s Primary School, Gorey, Co Wexford

Schools subject to ongoing structural assessment and analysis include:

Lucan Community National School, Balgaddy Rd, Dublin

Griffeen Valley Educate Together National school, Dublin

Gaelscoil na gCloch Liath, Wicklow

Rush and Lusk Educate Together National School

St Francis of Assisi Primary School, Belmayne

Belmayne Educate Together National School

Gaelscoil Mhichíl Uí Choileáin, Clonakilty, Co Cork

Cara Junior (Special) School, Cork

Galway Educate Together National School

Carrigaline Educate Together National School, Co Cork

St Colman’s Boys National School, Macroom, Co Cork

Gaelscoil Mhic Aodha, Kildare

Mullingar Educate Together National School, Co Westmeath

School building closed:

Ardgillan Community College (Phase 1 only), Dublin