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.
According to the Oxford English Dictionary , eaves is derived from the Old English efes (singular), meaning "edge", and consequently forms both the singular and plural of the word. [1] [2] This Old English word is itself of Germanic origin, related to the German dialect Obsen, and also probably to over. [3]
The Merriam-Webster dictionary lists the word as eave but notes that it is "usually used in plural". [4]
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. [5]
The eaves overhang may also shelter openings to ventilate the roof space. [6]
Aesthetic, traditional, or purely decorative considerations may prevail over the strictly functional requirements of the eaves. The Arts and Crafts Movement influenced the American Craftsman tradition, which has very wide eaves with decorative brackets technically called modillons, for which there is not necessarily a real functional need; likewise the Italian-style eaves.
The eaves may terminate in a fascia, a board running the length of the eaves under the tiles or roof sheets to cap off and protect the exposed rafter ends and to provide grounds on which to fix gutters. At the gables the eaves may extend beyond the gable end wall by projecting the purlins and are usually capped off by bargeboards to protect the wall and the purlin ends. The overhang at the gable is referred to as a gable overhang, as opposed to eave overhang, or they both may be referred to as overhang.
The underside of the eaves may be filled with a horizontal soffit fixed at right angles to the wall, the soffit may be decorative but it also has the function of sealing the gap between the rafters from vermin and weather.
Eaves must be designed for local wind speeds as the overhang can significantly increase the wind loading on the roof. [7]
The line on the ground under the outer edge of the eaves is the eavesdrip, or dripline, and in typical building planning regulations defines the extent of the building and cannot oversail the property boundary.
In architecture, a cornice is generally any horizontal decorative moulding that crowns a building or furniture element—for example, the cornice over a door or window, around the top edge of a pedestal, or along the top of an interior wall. A simple cornice may be formed just with a crown, as in crown moulding atop an interior wall or above kitchen cabinets or a bookcase.
A gable is the generally triangular portion of a wall between the edges of intersecting roof pitches. The shape of the gable and how it is detailed depends on the structural system used, which reflects climate, material availability, and aesthetic concerns. The term gable wall or gable end more commonly refers to the entire wall, including the gable and the wall below it. Some types of roof do not have a gable. One common type of roof with gables, the 'gable roof', is named after its prominent gables.
A soffit is an exterior or interior architectural feature, generally the horizontal, aloft underside of any construction element. Its archetypal form, sometimes incorporating or implying the projection of beams, rafters or trusses over the exterior of supporting walls, is the underside of eaves. The vertical band at the edge of the roof is called a fascia. A soffit of an arch is frequently called an intrados.
A rafter is one of a series of sloped structural members such as steel beams that extend from the ridge or hip to the wall plate, downslope perimeter or eave, and that are designed to support the roof shingles, roof deck, roof covering and its associated loads. A pair of rafters is called a couple. In home construction, rafters are normally made of wood. Exposed rafters are a feature of some traditional roof styles.
A knee wall is a short wall, typically under three feet in height, used to support the rafters in timber roof construction. In his book A Visual Dictionary of Architecture, Francis D. K. Ching defines a knee wall as "a short wall supporting rafters at some intermediate position along their length." The knee wall provides support to rafters which therefore need not be large enough to span from the ridge to the eaves. Typically the knee wall is covered with plaster or gypsum board.
A batten is most commonly a strip of solid material, historically wood but can also be of plastic, metal, or fiberglass. Battens are variously used in construction, sailing, and other fields.
A bargeboard or rake fascia is a board fastened to each projecting gable of a roof to give it strength and protection, and to conceal the otherwise exposed end grain of the horizontal timbers or purlins of the roof. The word bargeboard is probably from the Medieval Latin bargus, or barcus, a scaffold, and not from the now obsolete synonym vergeboard.
An attic is a space found directly below the pitched roof of a house or other building. It is also known as a sky parlor or a garret. Because they fill the space between the ceiling of a building's top floor and its slanted roof, attics are known for being awkwardly-shaped spaces with difficult-to-reach corners and often exposed rafters.
A purlin is a longitudinal, horizontal, structural member in a roof. In traditional timber framing there are three basic types of purlin: purlin plate, principal purlin, and common purlin.
This page is a glossary of architecture.
Domestic roof construction is the framing and roof covering which is found on most detached houses in cold and temperate climates. Such roofs are built with mostly timber, take a number of different shapes, and are covered with a variety of materials.
Fascia is an architectural term for a vertical frieze or band under a roof edge, or which forms the outer surface of a cornice, visible to an observer.
A bracket is an architectural element: a structural or decorative member. It can be made of wood, stone, plaster, metal, or other media. It projects from a wall, usually to carry weight and sometimes to "...strengthen an angle". A corbel or console are types of brackets.
A downspout, waterspout, downpipe, drain spout, drainpipe, roof drain pipe, or leader is a pipe for carrying rainwater from a rain gutter.
The hidden roof is a type of roof widely used in Japan both at Buddhist temples and Shinto shrines. It is composed of a true roof above and a second roof beneath, permitting an outer roof of steep pitch to have eaves of shallow pitch, jutting widely from the walls but without overhanging them. The second roof is visible only from under the eaves and is therefore called a "hidden roof" while the first roof is externally visible and is called an "exposed roof" in English and "cosmetic roof" in Japanese. Invented in Japan during the 10th century, its earliest extant example is Hōryū-ji's Daikō-dō, rebuilt after a fire in 990.
Roofline is used to describe the fascia, soffits, bargeboards and antefixes that forms the frontage immediately below the roof and the eaves of many homes and buildings. These are traditionally made from wood, but can be made of a variety of different materials, including plastic, such as polyvinyl chloride.
A hip roof, hip-roof or hipped roof, is a type of roof where all sides slope downwards to the walls, usually with a fairly gentle slope. Thus, a hipped roof has no gables or other vertical sides to the roof.
A post is a main vertical or leaning support in a structure similar to a column or pillar, the term post generally refers to a timber but may be metal or stone. A stud in wooden or metal building construction is similar but lighter duty than a post and a strut may be similar to a stud or act as a brace. In the U.K. a strut may be very similar to a post but not carry a beam. In wood construction posts normally land on a sill, but in rare types of buildings the post may continue through to the foundation called an interrupted sill or into the ground called earthfast, post in ground, or posthole construction. A post is also a fundamental element in a fence. The terms "jack" and "cripple" are used with shortened studs and rafters but not posts, except in the specialized vocabulary of shoring.
A Bresse house is a timber-framed house of post-and-beam construction, that is infilled with adobe bricks and is typical of the Bresse region of eastern France. A large hip roof protects the delicate masonry from rain and snow. The house is almost always oriented in a north–south direction, the roof on the north side often being lower. This configuration offers the optimum protection from the bise, a cold northerly wind typical of the region, which is deflected over the house by the low, sweeping roof on the northern gable end. The living rooms are on the south side, the main façade facing the morning sun. Usually each room has one or two outside doors, so that no space is sacrificed for passages.
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