The Ontario Building Code | Required Flashing at Intersections Required Flashing at Intersections

(1) Except where the omission will not adversely affect adjacent supported or supporting elements, flashing shall be installed at junctions between roofs and,

(a) walls that rise above the roof, and

(b) guards that are connected to the roof by other than pickets or posts.

(2) For the purpose of Sentence (1), roofs shall include platforms that effectively serve as roofs with respect to accumulation or drainage of precipitation.