How Far Should Roof To Wall Flashing Overhang The Eaves

Roof overhangs at the eaves and rakes protect the walls below from rain and sun.

How far should roof to wall flashing overhang the eaves.

An eave typically has a metal edge flashing and gutter that are attached to a wood fascia trim board. Eaves form the overhang to distribute water clear of the walls. Eaves are located at the down slope edge of a sloped roof and serve as the transition between the roof and fascia wall. But are they really necessary.

With composite siding such as boral s truexterior siding over a ventilated rain screen and with properly executed flashing at the windows and doors the walls on the fhb house will be able to handle rain just fine. One common method is to lay the edge metal under the eaves membrane and over the rake image. They also help to frame windows on upper stories. This can make extensive roof overhangs more trouble than they are worth in all but the harshest climates.

Overhangs are extensions of the roof beyond the exterior wall i e the joists. An eave is the edge of the roof that overhangs the face of a wall and normally projects beyond the side of a building. Roof overhangs can extend farther than 2 feet but beyond this length they begin to lose structural integrity and require external supports. Protect the eave from ice dams and sideways rain step one in steep slope roofing is the edge flashing.

A typical metal roof overhang may be 2 to 4 inches or even less. However the suggested width of an overhang is between 12 and 18 for eaves and no more than 8 for rakes. The edge of the shingles should hang over a roof between an inch and an inch and a half or between a half inch and three quarters of an inch if drip edge flashing is installed. Two feet is the general maximum length for a typical roof overhang.

Metal is usually installed on rafters or strip sheathing rather than the solid decking used under other materials. Too little can allow water to seep into rake or fascia boards. The sketch above illustrates the end profile of roof drip edge flashing and shows its placement on the roof. Some slight overhang is recommended in conjunction with a drip edge flashing to prevent water from getting under the roofing and onto underlying wood.

This will protect a roof from most types of damage. Too much overhang and the shingles could blow off in high winds. Usually you won t see much of drip edge as it s under the roof shingles under the underlayment and behind the roof gutter.