The Ontario Building Code | Flashing Materials
9.27.3.7. Flashing Materials
(1) Flashing shall consist of not less than,
(a) 1.73 mm thick sheet lead,
(b) 0.33 mm thick galvanized steel,
(c) 0.46 mm thick copper,
(d) 0.46 mm thick zinc,
(e) 0.48 mm thick aluminum, or
(f) 1.02 mm thick vinyl.