MT&T already owned land at the corner of Spring Garden Road and Barrington Street, and the Capitol Theatre was for sale, allowing the company to enlarge the site.

[1] Construction was delayed by the discovery of a rock fault beneath the site, which compelled the developers to undertake costly remedial action to protect the adjacent St. Matthew's Church.

[6][5] The first phase of the tower had included extra, empty elevator shafts that were put into service with the expansion of the building, estimated in 1982 to cost C$24 million.

The same principal consultants that had worked on phase one of the complex were also employed on the addition project, namely: Webb Zerafa Menkes Housden (architecture firm), George Brandys & Associates (structural engineer), and Robert McAlpine Ltd. (general contractor).

[7] On October 13, 2015, Fortis Inc. announced that it had sold its commercial real estate portfolio, including Maritime Centre, to Slate Office REIT.

In November 1973, the president of MT&T, Gordon Archibald, stated that the tower would not block the view of George's Island from the hill.

The plazas and steps in front of the building entrances, along Barrington Street, were replaced with expanded lobby, vestibule, and retail areas.