Eaves

The eaves are the edges of the roof which overhang the face of a wall and, normally, project beyond the side of a building. The eaves form an overhang to throw water clear of the walls and may be highly decorated as part of an architectural style; such as the Chinese dougong bracket systems.

Etymology and usage

Eaves is derived from Old English efes meaning edge. According to the Oxford English Dictionary, eaves is both the singular and plural form of the word. However, the Merriam-Webster website lists the word as eave and states that it is "usually used in plural". The word was used before the 12th century in the form efes (Old English).

Function

The primary function of the eaves is to keep rain water off the walls and to prevent the ingress of water at the junction where the roof meets the wall. The eaves may also protect a pathway around the building from the rain, prevent erosion of the footings, and reduce splatter on the wall from rain as it hits the ground.

The secondary function is to control solar penetration as a form of passive solar building design; the eaves overhang can be designed to adjust the building's solar gain to suit the local climate, the latitude and orientation of the building.