Willmott Dixon will now start work in March on the Eastern High School on land formerly used by Cardiff and Vale College for its Trowbridge campus in the east of the City.
Under its design and build contract Willmott Dixon is using a standardised design for the school, saving the taxpayer money and significantly reducing the risk to the council.
The L-shaped school will accommodate 59 classrooms, three flexible open teaching spaces, a main hall, dining area, kitchens and gym.
Sport facilities include a rugby pitch, with a baseball diamond and eight-lane 110m hurdle track, as well as a 3G football pitch, a multi-use games areas for football or basketball, and a long jump pit.
The facilities are to be floodlit and a grandstand with 60 seats is proposed next to the eastern side of the football pitch.
The new school and college for 11-18 year olds will be ready for September 2017.
