Hundreds of pupils in Buckinghamshire won't be able to return to school this week because RAAC concrete has been found in its buildings.
Waddesdon Church of England School, near Aylesbury, says it's been given no option but to take the emergency measures to ensure the safety of its pupils.
The school is due to reopen on Wednesday, but it's thought more than half of the 1,000 pupils will be have to stay at home with lessons online.
The restaurant and sections of the main block are potentially impacted by RAAC concrete, which can be dangerous, and cause buildings to collapse.
In a letter to parents the school said the English, History, Religious Studies, Geography, Technology, Music and Drama departments could be affected.
Years 7, 8 & 12 will receive face- to- face teaching but online learning will be given to students in Years 9, 10, 11 & 13 via Teams at home.
Waddesdon is one of a number of schools in the region affected by RAAC concrete, which was used to construct buildings in the 1950s.
The political row over the concrete rages on with Labour saying the Government knew about the dangers but failed to act. The Government say it did act appropriately.
Meanwhile the school here is expected to give parents an update on the situation on Monday.
It's not known how long they will be in place or when all pupils will be able to return to school.
What is RAAC?
Reinforced Autoclaved Aerated Concrete (RAAC) is a lightweight form of concrete.
The way that RAAC is created makes it weaker than the normal building material.
There is no coarse aggregate - for example gravel and crushed stones - in RAAC, this is what gives concrete its strength.
Instead fine aggregate - such as sand and stone particles - is combined with chemicals to create gas bubbles, and heat to cure the compound. This makes it relatively weak.
In some schools roofs are constructed using RAAC planks, which are long slim blocks of the material.