A Derbyshire school will remain closed to some pupils for a further two weeks after builders working on the site declared it unsafe for use.
Contractors have been working to replace the slate roof at Heanor Langley Infant School and Nursery over the holidays to minimise disruption.
However builders have now discovered that roof trusses and joists in the 19th century building are rotten and more work is required before children can return.
All pupils had been due back for the first day of term on Tuesday, September 8.
Plans are now in place for Year 2 to start lessons in usable parts of the school on Monday, September 14. All other year groups will follow a week later on September 21.
Headteacher Carol Daly said: “I understand this news is unwelcome and puts many parents in difficult positions over work and childcare.
“However we are doing what we can to offer off-site activities for the children that cannot return to school and I’ll keep in touch with parents about these.”
Information about the closure has been posted on the school’s website and parents have been informed by text.
Daly added: “Everyone connected with the school should stay in touch through our website, where we also hope to put some work for children to do while they remain off.”
Derbyshire County Council, which is funding the £138,000 renovation project, say they have ruled out all possible options to avoid the closure which affects 120 infant and 34 nursery children.
The school site is too small to accommodate temporary buildings, and there are no other suitable venues nearby.
Councillor Jim Coyle, cabinet member for children and young people, said: “I totally understand what effect this news will have on children and parents and I apologise for the inconvenience caused.
“However the safety of staff and pupils is our top priority.”