Eaves are the edges of the roofline that extend beyond the face of the exterior walls. They have both aesthetic and practical functions. Eaves are designed to project water away from the side of a building, protecting the siding and the home’s exterior from extensive water damage. On a standard residential structure, the eaves are finished with fascia boards, which support the gutters. More importantly, the roof overhang keeps rain and snow off someone as they enter the home or pause to open an umbrella when leaving.
Word Usage and Origin
While “eave” is the accepted singular form, “eaves” is used as both the singular and plural of the word. Its origin is efes, the Old English for “edge” or “border.” Manuscripts and other source materials indicate the word was in use around mid-eleventh century or even before. Eaves has etymological connections with Old Frisian ose for “eaves,” Old High German obasa for “porch,” and German oben meaning “above.” From Middle English evisdroppyr, an eavesdropper is someone standing on the eavesdrop close enough to the house to hear what is going on inside.
Purpose of Eaves
Eaves keep rainwater or melting snow from coming into direct contact with exterior walls, protecting siding, windows, and the foundation of a house. If the roofline ended at the top of an outside wall (no overhang) rain would fall from the roof straight to the ground, seeping into the siding and pooling too close to the foundation. An eave also helps prevent water from entering a home where the exterior walls connect with the roof.
An eave with a pronounced overhang can provide shade to the interior of a south facing house. Extended eaves shelter people from inclement weather in addition to directing water away from the building.
Eaves of multilevel roofs may also be designed to direct sunlight into a home to heat the interior in winter, and then block the sun in the summer.
An overhang can enhance or even define the architectural style of a house. Eaves are one of several exterior finishing elements that impact the overall appearance and style of your home. Of course, the wider the eaves, the more protection it offers, but they can support larger sized gutters should a home need a 6-inch or 7-inch gutter system.
Types of Eaves
The four basic types of eaves are exposed, soffited, boxed-in, and abbreviated. Eaves typically include fascia, the material used to close off the ends of the rafters from the elements. When standard gutters are used on a residential structure, they are generally attached to the fascia. All types of eaves excluding the abbreviated eave typically include some kind of ventilation system to prevent condensation from forming on the roof (outside) or in the attic (inside).
Exposed eaves allow the roof overhang and its supporting rafters to be seen from the ground when looking up. The main drawback with exposed eaves is it’s the ideal home for wasps, hornets, bees, and birds – the wider the overhang, the more inviting a space for insects and birds.
When the ends of the rafters aren’t visible, the eaves are soffited. Soffit panels cover the underside of the eaves by connecting the bottom tip of the eave to the top of the exterior wall.
While the rafters are still visible, boxed eaves enclose the underside to rain and wind.
An abbreviated eave is closed to the elements and has little overhang.
By Design
By design, eaves are primarily functional. They should be specifically adapted to local wind speeds, since an overhang can increase wind loading (force on a structure resulting from the impact of wind on it) on the roof.
The line on the ground directly under the outer edge of the eaves is referred to as the eavesdrip, eavesdrop, or dripline.
For aesthetic reasons, eaves can be combined with patterned fascia boards and/or embossed or imprinted soffit panels.
