Drawn up by Birmingham-based D5 Architects and world-famous balloonist Per Lindstrand, the £2.5 million project has been designed to create a column-free, three-storey concourse.
The 1,100m 2translucent roof is made from a white PVC-coated fabric and is split into three independent sections, so that if one piece should deflate the remaining two will keep the roof structurally sound.
Using aeronautical engineering techniques, the self-supporting roof took almost a year to design, but was manufactured and installed in only eight weeks.
The structure was delivered to the site on a flat-bed lorry as a single cylinder and lifted onto the steel frame using a crane. It took just two hours for six fans to inflate the entire roof before it was strapped on.
Describing the project, Ian Saunders, a partner at D5 Architects, said: '[the roof's] design and development represents an aesthetic solution that creates a balance between a unique spatial experience and the innovative use of technology.'
Redevelopment backers BAA and coach operator National Express said they hoped the scheme would improve the 'environment' for the eight million passengers who pass through the station each year.