Further talks are taking place this week between teacher unions and Department of Education officials on how to safely reopen schools in late August.
Concerns are emerging about the number of substitute teachers available to cover classes and how expensive cleaning bills will be paid.
Teachers with cold and flu symptoms will have to stay home and not go into schools from late August.
Unions say this will lead to a dramatic increase in the number of substitute teachers being called upon because classes will not be split.
It could mean schools will not reopen until a full panel of substitute teachers is available.
Teachers and school managers are also worried about who will pay for the daily cleaning and hand sanitizers needed with some estimates suggesting it could cost €24m before Christmas.
A lot of schools have a part-time cleaner which now needs to be scaled up considerably but ancillary grants only cover basic cleaning.
Those issues will dominate the talks on reopening schools safely which resume tomorrow.