The deal for developer Rightacres at its flagship Central Square scheme is the contractor’s biggest win of the the year.

The mixed-use project includes a 14-bay bus interchange with a covered concourse, 318 apartments for the Private Rented Sector and 90,000 sq ft of office space.

The project is being funded by Legal & General and designed by Cardiff-based Holder Mathias Architects.

ISG has an ongoing relationship with Rightacres after successfully delivering the new Foster + Partners designed BBC Cymru Wales headquarters building and Two Central Square, home to Hugh James and Cardiff University’s School of Journalism.

The Cardiff Transport Interchange building will use off-site manufactured bathroom pods and a slip form system to accelerate construction of the concrete cores.

ISG will use an enclosed four-storey platform on a jacking system to sequentially form the reinforced concrete frame and immediately weather proof each floor as the platform rises up the tower.

Kevin McElroy, ISG project director,said: “The Cardiff Interchange has been one of the most highly anticipated developments of recent years and this announcement reflects real collaboration and vision from all project stakeholders to create a mixed-use scheme that delivers for our city.

“Not only will this dramatically improve connectivity for businesses, residents and visitors to Cardiff, but alongside the iconic BBC Wales headquarters, will transform this strategic gateway site.”

Jason Hyett, Rightacres project director, commented: “The signing of the build contract marks a great landmark in the project’s timeline and is thanks to the input of a great number of people.

“We look forward to working with ISG and the project team to deliver, what will be, another great building in the city”

Stephen Hill, Holder Mathias partner, said: “The interchange is an extremely complex, challenging and multi-layered project that, once complete, will provide a modern, innovative and truly mixed-use set of environments.”