Why this is happening
Lots of schools in the 1950s and later were built using a material called reinforced autoclaved aerated concrete (also known as RAAC). It was used because it was cheaper and easier than other building materials at the time.
RAAC doesn’t last as long as other types of building materials, this means it can start to get weaker and become unsafe after a certain amount of time. Because lots of the buildings that use RAAC are older, people are worried that they might not be safe for students to keep learning in.