I looked it up on the old aerial photo cache the University of Waterloo has and the same building is there as far back as 1930.
It's actually not uncommon to find buildings built in the first quarter of the 20th century that lack ornamentation like this. The Bauhaus and similar modernist movements started out around the early 1900s and were rapidly taking over aesthetic and theoretical design ideas at the time. It wasn't until around the 1950s when modernism eventually triumphed over more classical design, so you do see a lot of buildings built between 1900 to 1949 that still had lots of details. But even by then, the design ideas of modernism - with a lack of what was perceived to be frivolous ornamentation - was quite common to see. The rear of Adolf Loos' Steiner House is a great example and this was built in 1910. Walter Gropius and Adolf Meyer's das Fagus-Werk is another great example (probably one of the best) and this gorgeous factory was built between 1911 and 1913. The 20th century saw a huge cultural shift between classicism and modernism, which helped give rise to things like fascism as there was a huge conflict between the old world and the modern world. So it was a period with a lot of both as the world was rapidly changing thanks to the industrial revolution, mechanical reproduction and new ideas in philosophical and practical aesthetics. Hitler and others actually hated the Bauhaus movement! It was "degenerate art" to them, but thankfully persevered and won over nonsensical conservatism.
Anyway, here's the aerial photo below. The quality is terrible but unfortunately the University of Waterloo doesn't have higher resolutions available...they really need to rescan these old photographs. Here's another one from 1945 as well which has a better resolution. The yellow highlights what is now Charles Street for reference, as it's a bit hard to tell it's the same building in the photo from 1930. I'm making a complete guess but I'd say this building is from maybe 1928 or so and that the architect was inspired by early modernism (or they just didn't want to spend a lot of money on ornamentation, though that's more unlikely).
It's actually not uncommon to find buildings built in the first quarter of the 20th century that lack ornamentation like this. The Bauhaus and similar modernist movements started out around the early 1900s and were rapidly taking over aesthetic and theoretical design ideas at the time. It wasn't until around the 1950s when modernism eventually triumphed over more classical design, so you do see a lot of buildings built between 1900 to 1949 that still had lots of details. But even by then, the design ideas of modernism - with a lack of what was perceived to be frivolous ornamentation - was quite common to see. The rear of Adolf Loos' Steiner House is a great example and this was built in 1910. Walter Gropius and Adolf Meyer's das Fagus-Werk is another great example (probably one of the best) and this gorgeous factory was built between 1911 and 1913. The 20th century saw a huge cultural shift between classicism and modernism, which helped give rise to things like fascism as there was a huge conflict between the old world and the modern world. So it was a period with a lot of both as the world was rapidly changing thanks to the industrial revolution, mechanical reproduction and new ideas in philosophical and practical aesthetics. Hitler and others actually hated the Bauhaus movement! It was "degenerate art" to them, but thankfully persevered and won over nonsensical conservatism.
Anyway, here's the aerial photo below. The quality is terrible but unfortunately the University of Waterloo doesn't have higher resolutions available...they really need to rescan these old photographs. Here's another one from 1945 as well which has a better resolution. The yellow highlights what is now Charles Street for reference, as it's a bit hard to tell it's the same building in the photo from 1930. I'm making a complete guess but I'd say this building is from maybe 1928 or so and that the architect was inspired by early modernism (or they just didn't want to spend a lot of money on ornamentation, though that's more unlikely).