A new contractor will soon start work on the next phase of works at Woodlands Meed College in Burgess Hill.
West Sussex County Council has appointed Sunninghill Construction after the previous contractor entered administration last year.
Sunninghill has already completed ground clearance and enabling works and will now start on a new all-weather pitch and additional car parking among other works in this phase.
Staff and pupils at Woodlands Meed College moved into the new main building last year after it was handed over to the school by the council.
The multi-million pound development is providing new facilities including a hydrotherapy pool, 12 new classrooms and a two-court sports hall for 100 children with special educational needs and disabilities.
These are in addition to the all-weather pitch and outside multi-use games area and amphitheatre where children can sit together and hold sporting and social events.
Cllr Jacquie Russell, Cabinet member for Children and Young People, Learning and Skills, said: “We’re pleased to appoint Sunninghill and are looking forward to working with them and the school to ensure the works are completed as soon as possible and to the highest standard that we, the staff, pupils and their families expect. We’re developing facilities at Woodlands Meed that will help young people at the school, both now and in the future, to fulfil their potential.”