The 12,000-seat arena, which is being constructed by Lend Lease, is due to be completed in by spring 2013 and will be a key venue for the corporate events market and the 2014 Commonwealth Games.
Gordon Anderson, executive general manager of Lend Lease, said: "This is the most complex feat of engineering in Scotland this year, and is a major step forward in The Hydro’s construction process."
"The next step involves the positioning of 16 roof segments between the perimeter of the building and the central section. These 36m long segments have been assembled in the SECC car park over recent weeks and are now ready to be put in place.
"Once they are in place, the temporary tower can be removed and the roof will then support its own weight."
John Sharkey, SECC’s chief executive, added: "We are delighted to have reached this milestone in the construction of The Hydro. It has been a complex procedure and represents a great achievement by Lend Lease and the project team and we congratulate them."