Some students may be taught in parish halls or GAA facilities when they return to school next month.
Children from junior infants to second class won't have to observe social distancing but all others will have to be spaced a metre from their classmates.
75 million euro is being allocated to allow schools adapt their classrooms.
ASTI General secretary Kieran Christie says they will also be looking to the community to find space.
Meanwhile the Education Minister has said there's no shortage of available primary school teachers to utilise as part of the plan to re-open schools.
The plan includes money for increased substitution in case a teacher gets sick or can't work because they're in a vulnerable category.
There's also money to recruit more than 1,000 extra secondary school teachers to help reduce class sizes.
Education Minister Norma Foley believes they can find that amount of teachers within the country to work
But John Boyle from the INTO is concerned the numbers won’t be enough in urban areas.
