Using 2001 and 2011 census data, I made a map of where the number of housing units added in Kitchener, Waterloo and Breslau. One red dot is 30 new housing units. Northward actually had a slight decrease in housing units (black dot).
The data was by census tract, so if it was relatively evident where within the census tract the new housing was built, I'd add the dots there, otherwise I'd just spread them out evenly. Although KW did not see much of an increase in population within the built up area due to decreasing household sizes, the number of housing units did increase throughout, especially in Downtown, Uptown and around Northdale (which technically lost population since students are not counted).
Of course not all housing units are equal. The apartments in Northdale and houses on the outskirts are bigger and hold more people than apartments Downtown. There appears to have been a small infill townhouse and SFH developments throughout KW, but some census tracts that do not seem to have any new construction saw increases in the number of units too. For example, Lakeshore Village saw an increase in 166 housing units, perhaps due to the creation of basement apartments?
Although the majority of growth was suburban during this period, core growth was still significant, and it will be interesting to see how different things will be by the 2016 census with the increased growth in the core areas.