For over a decade, the Concourse Building has been on borrowed time. The art deco office building, whose unique features include mosaics designed by Group of Seven artist J.E.H. MacDonald, has waited while its owner, Oxford Properties, decided how to place a new tower on the site. The latest design for 100 Adelaide Street West might be a lovely building on its own—the top of its glass tower vaguely resembles the originally promised design of the ROM crystal—but, at first glance, the inclusion of the facade of a gutted Concourse Building resembles a pasted-on afterthought. If realized, the tower would join the long list of examples of facadism found around Toronto’s core.

A few months ago, Torontoist wrote about the practice of façadism in the downtown core. Façadism—which refers to the practice of retaining the front face, or "skin," of an old building and affixing it to a newer, usually larger structure—has become increasingly popular in recent years as the city continues to grow up and out at its breakneck pace. Façadism began to be seen in Ontario after the 1975 Heritage Act, which gave municipalities...