A number of students at Sandal Magna Community Academy have been forced to learn in temporary classrooms while long-running and expensive repairs to a leaky school roof are finished.
Wakefield Council said in October that the work would be completed before Christmas, with pupils back in the building by November 27, but the scheme has now been hit by more complications.
As a result, the children are now due to be back in the revamped building in the new year.
Scaffolding which was due to be removed on December 17 is now scheduled to be taken away in January instead.
Asked for an update on the scheme at a meeting on Wednesday, the council's Cabinet member for children, Margaret Isherwood said: "Unfortunately there has been a delay, so it will be another couple of weeks.
"But the children are attending school. They are in temporary accommodation which is very good.
"We've had no other concerns raised by the school at this time.
"But there has been a delay in the removal of the scaffolding, it will be just another couple of weeks after the original date."
The school's defective structure has caused chaos ever since a new building was put up at the site in 2010, with pupils frequently forced off site due to leaks.
Attempts to fix it over the last decade have been constantly hit by setbacks and cost taxpayers millions.
A number of year groups have been taught in nearby council buildings, with parts of the school itself deemed unsafe and unfit.
Sandal Magna became an academy in 2013, but the council was deemed responsible for the repairs as the school was under its stewardship when the building up was put up in 2010.
Findings from an independent inquiry earlier this year exposed a number of failings and was critical of the council's management of the project.
It also recommended the authority change its approach to industrial contracts. It had previously been revealed that £430,000 had been paid to a roofing firm over a six-month period, despite them having been unable to do any work in that time.
Local Democracy Reporting Service