Montreal, June 12, 2009. The 424-410 Ontario Street East. Estimated Construction: 1875. Ontario Street is officially opened in 1864. Curious alignment demaisons row arranged in "sawtooth". Again, material characteristics of the time: rusticated gray stone of Montreal, channel framing and corner windows in stone, false mansard roof covered with slate shingles in various designs, small dormers crafted hat. Of firewalls separating each house.