The Ontario Building Code | Location of Flashing

9.20.13.3. Location of Flashing

(1) Flashing shall be installed in masonry and masonry veneer walls,

(a) beneath jointed masonry window sills,

(b) over the back and top of parapet walls,

(c) over the heads of glass block panels,

(d) beneath weep holes, and

(e) over the heads of window and door openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings in exterior walls when the vertical distance between the top of a window or door frame and the bottom edge of the eave exceeds one-quarter of the horizontal eave overhang.

(2) Throughwall flashing shall be provided in a masonry veneer wall such that any moisture that accumulates in the air space will be directed to the exterior of the building.