Contractor Bramall Construction has started work on the £12m refurbishment and rebuild of Loreto High School in Chorlton.
The project, designed by Ellis Williams Architects, will see the remodelling of an existing three storey teaching and technology block, as well as the construction of a new three storey extension to the main entrance area to provide a new library.
The new-build element, funded through the Building Schools for the Future programme, is due for completion in February 2011 and the rest of the work by November 2011.
The 750-place school on Nell Lane will also have extra teaching and resource spaces for both the school and community, as well as new facilities for English, humanities and science, and there will also be the demolition of a small administration block.
Headteacher, Luke Dillon, said: "The new building programme represents a very important step on our journey to providing outstanding educational opportunities and facilities for the catholic children of our feeder primary schools. The interior and exterior of the new building will stimulate students and provide them with the first class accommodation they deserve. We are very excited about the new project."