COP v3.0:installation; overhang

14.10 Overhang 

The length of the overhang of sheeting into a gutter or spouting depends on the pitch of the roof and the site exposure to wind and rain.

The minimum overhang for roof cladding with a pitch between 10° and 35° is 50 mm, and 40 mm is regarded as suitable for a roof above 35°. When the ends of the ribs are not baffled by a spouting and the pitch is below 10°, the overhang should be increased to 70 mm to avoid blow-back.

Underlay must not overhang the gutter line by more than 20 mm, or if eaves flashings are used, terminate on the upper side of the flashing.