The Ontario Building Code | Location of Flashing
220.127.116.11. Location of Flashing
(a) beneath jointed masonry window sills,
(b) over the back and top of parapet walls,
(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.