Norfolk's largest academy trust has ordered safety checks on of almost half of its schools.
The Diocese of Norwich Education and Academies Trust has called in surveyors to assess 18 of its sites with lath and plaster ceilings.
It comes after three schools were forced to temporarily close earlier this term over safety issues with their aged classroom roofs.
At the beginning of September, Fakenham Junior School and Reepham Primary School, both had to shut to pupils while surveys were carried out.
As a result, Norfolk County Council ordered checks on several of its maintained schools, which also saw Avenue Junior School in Norwich forced to close for three days.
County Hall then urged academy trusts to investigate the states of their own sites - particularly those containing plaster and lath ceilings.
Oliver Burwood, chief executive officer of DNEAT, confirmed checks are set to be carried out in 18 of its schools.
The organisation is responsible for 42 establishments in the county - more than any other trust - meaning almost half of its sites are affected.
Mr Burwood said: "We have identified 18 our of 42 schools that either have or could have lath and plaster ceilings.
"I have written to parents of these schools that we have asked headteachers and site staff to visually check all ceilings and no issues were identified via this process.
"DNEAT has also commissioned a specialist survey company to fully survey all ceilings in these 18 schools.
"We can then plan appropriate next steps based on the survey information but will clearly prioritise the replacement of any ceilings that could cause issues in the short to medium term."
Meanwhile, another of the region's academy trusts, the Wensum Trust, has carried out checks on two of its 11 schools - but identified no safety issues.
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