Eave

The eave is the bottom edge of a sloped roof, the horizontal line where the roof overhangs the wall along the long sides of the house. It is distinct from the rake edge, which runs up the sloped, gable side of the roof instead.

Several separate systems converge at the eave. The soffit closes off the underside of the overhang, the fascia caps the rafter ends and holds the gutters, and drip edge guides water off the shingles and into those gutters rather than back under them.

Because every drop of water on a sloped roof eventually runs down to an eave, that edge handles far more moving water over its length than the open field of the roof above it.

That concentrated flow is why the eave gets extra protection. Building codes in colder regions require an ice barrier at the eave to guard against ice dams, and in warmer climates without that code trigger, quality installations still add a course of ice and water shield there by choice, on top of standard drip edge and underlayment.

It is also why gutters are hung at the eave rather than anywhere else. A gutter's whole job is to catch the water shedding off the eave before it reaches the ground and the foundation.

For a homeowner, the eave is the place to check after a hard rain, since so many separate systems share those few inches of roofline.

Water pouring over the gutter, staining on the fascia, or a soft spot in the soffit there usually points to a problem right at the eave rather than somewhere higher on the roof.