Work is set to begin on a £15m scheme to transform Darlington's largest secondary school.
Some of the buildings at Hummersknott School and Language College, in Edinburgh Drive, date from the 1950s and will be demolished and replaced.
Other buildings will be refurbished during the work, which follows consultation with pupils, parents, staff and local residents.
A turf-cutting ceremony will mark the start of the work on Monday.
Chris McEwan, Darlington Council's cabinet member for children's services, said: "This is a hugely important project that will help us in our drive to raise standards for children across Darlington.
"Hummersknott School has been part of the local community for more than 50 years and this development will ensure it continues to provide pupils with an excellent start in life for many years to come."
The government has allocated £11.6m for the project, with Darlington Council contributing a further £2.7m, and the school £700,000.