Work is continuing over the weekend to ensure that 22 schools with structural issues are safe for the return of pupils on Monday.
More than 250 workers are engaged at the various sites installing protective fencing and other precautionary measures to allow the schools to re-open.
Even with the precautionary measures, three schools will be able to open only their ground floor: Tyrrelstown Educate Together and the neighbouring St Luke's NS, and Gaelscoil Eiscir Riada, Lucan, all in County Dublin.
In these schools, as well as safety fencing and protective decking at entrances to the building, internal timber supports are being installed to ensure safe occupation of the ground floor.
In a letter to principals yesterday, the Department of Education said assessments on these schools were ongoing and they hoped to have more clarity over the next week.
In another 19 cases, where there is a "potential issue with an external wall", safety fencing and protective decking at entrances are being put in place, pending further investigation. The schools have been cleared to open in full, although play areas may be restricted.
According to the department's letter, no other school presented the same severity of structural issues as those identified in the Phase 1 building of Ardgillan Community College, Balbriggan, Co Dublin, which remains closed pending remediation work.
"The issues identified at other schools do not relate to the load-bearing elements of the building structure", the letter added.
It stated that the approach throughout the process of assessing 42 schools over the past week, was to "err on the side of caution in relation to deciding whether internal or external precautionary measures were necessary in order to facilitate safe occupancy".
Principals have been asked to be available tomorrow for an on-site handover from the project managers of a written confirmation that the precautionary measures have been completed and appropriately certified.
In a recent Dáil debate, Education Minister Joe McHugh said "student and teachers' lives have been put at risk".