The youngsters were attending Cubs, Beavers and Scouts clubs at Tranent Parish Church Hall when sections of material gave way.
The Church of Scotland said the cause was not yet known but the body responsible for enforcing workplace safety in Great Britain had been informed.
In a statement, Church leaders said: "We have met with the Health and Safety Executive this morning and the building will be closed until further notice.
"We are very thankful that the injuries sustained were not more serious and we hope the children are now recovering.
"Our prayers are with everyone who was hurt or affected by this incident."
Police were called to the building on Church Street in Tranent shortly before 7pm. No one was seriously hurt.
One parent who was inside the hall at the time told Dundee-based newspaper, The Courier: "The ceiling plaster collapsed from the roof over a group of children, the Beavers, and it was chaos - walking wounded and one with head split open.
"The Beaver leader was distraught; three Beavers were being enrolled just as the ceiling came down over all the group.
"This could have been far worse."
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