Two Dublin schools have shut with immediate effect after problems were discovered during structural checks being carried out at 30 schools built by Western Building Systems.
More than 1200 children go to Tyrrelstown Educate Together and St Luke's National School in Mulhuddart.
Earlier this week, serious structural issues forced Ardgillan Community College in Balbriggan to close one of its buildings.
The Taoiseach, Leo Varadkar, says it's clear to him that corners were cut while schools were built during the Celtic Tiger.
The Department of Education says it is "working closely with the school authorities in relation to interim accommodation solutions for the over 1,200 affected pupils".
The target is to have interim accommodation solutions in place for when pupils return to school after the mid-term break next week.
"The investigations at Tyrrelstown today, while not identifying any imminent danger, suggest that those two schools should close as a precautionary measure", a statement explained.
In a statement, Educate Together said the Department of Education told it the Tyrrelstown ETNS building cannot be occupied whilst remedial works are being carried out.
"Educate Together expects that all students will be accommodated by the Department of Education after the mid-term break with interim accommodation solutions".
It is not yet clear what plan is in place for students of St Luke's National School in Mulhuddart.