Architects T. E. Julian and H. J. Williams designed the classic cruciform structure with narthex, nave, transepts and an apsidal chancel. Construction under the charge of R. P. Forshaw and Company took just 491 days.

Norman columns support the nave arcades which in turn support a Gothic tunnel vault. The columns are finished with a highly polished, red Scagliola marble. Non-structural ribs decorate the vault with simple molding accenting the intermediate ribs.

The cathedra sits in the middle of the sanctuary against a Gothic-style oak altar-piece with richly detailed gold foliage and angels set in relief. The towers of the reredos are also decked with delicately carved angels carrying torches, thuribles and sacred books.

Many updates have been made to the sanctuary over the years – the most significant changes being those for the Golden Jubilee, modifications decreed at Vatican Council II in the 1960s and some upgrades for the visit of Pope John Paul II in 1984.
Between 1995-1997, the Cathedral was re-roofed and the interior repainted between 2004-2006. Upgrades have been done to the stonework at the front entrance and sides as well as the pillars and floor. New light fixtures, pews and an upgraded sound system were added in 2018.

As with most heritage buildings, maintenance is an ongoing effort which depends on the good stewardship and kind support of its parishioners and friends.

The dimensions of the building are:

• 161 feet long
• 104 feet across at the transepts
• 62 feet across the nave and the aisles
• 62 feet from the floor ceiling
• 217 feet to the top of the larger steeple