A roof is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temperature, and wind. A roof is part of the building envelope.
A mansard or mansard roof is a multi-sided gambrel-style hip roof characterised by two slopes on each of its sides, with the lower slope at a steeper angle than the upper, and often punctured by dormer windows. The steep roofline and windows allow for additional floors of habitable space, and reduce the overall height of the roof for a given number of habitable storeys. The upper slope of the roof may not be visible from street level when viewed from close proximity to the building.
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 with a crown, as in crown moulding atop an interior wall or above kitchen cabinets or a bookcase.
A dormer is a roofed structure, often containing a window, that projects vertically beyond the plane of a pitched roof. A dormer window is a form of roof window.
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.
The steel square is a tool used in carpentry. Carpenters use various tools to lay out structures that are square, many of which are made of steel, but the name steel square refers to a specific long-armed square that has additional uses for measurement, especially of various angles. It consists of a long, wider arm and a shorter, narrower arm, which meet at an angle of 90 degrees. Today the steel square is more commonly referred to as the framing square or carpenter's square, and such squares are no longer invariably made of steel ; they can also be made of aluminum or polymers, which are light and resistant to rust.
A flat roof is a roof which is almost level in contrast to the many types of sloped roofs. The slope of a roof is properly known as its pitch and flat roofs have up to approximately 10°. Flat roofs are an ancient form mostly used in arid climates and allow the roof space to be used as a living space or a living roof. Flat roofs, or "low-slope" roofs, are also commonly found on commercial buildings throughout the world. The U.S.-based National Roofing Contractors Association defines a low-slope roof as having a slope of 3 in 12 (1:4) or less.
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 tented roof is a type of polygonal hipped roof with steeply pitched slopes rising to a peak. Tented roofs, a hallmark of medieval religious architecture, were widely used to cover churches with steep, conical roof structures.
Framing, in construction, is the fitting together of pieces to give a structure, particularly a building, support and shape. Framing materials are usually wood, engineered wood, or structural steel. The alternative to framed construction is generally called mass wall construction, where horizontal layers of stacked materials such as log building, masonry, rammed earth, adobe, etc. are used without framing.
Roof shingles are a roof covering consisting of individual overlapping elements. These elements are typically flat, rectangular shapes laid in courses from the bottom edge of the roof up, with each successive course overlapping the joints below. Shingles are held by the roof rafters and are made of various materials such as wood, slate, flagstone, metal, plastic, and composite materials such as fibre cement and asphalt shingles. Ceramic roof tiles, which still dominate in Europe and some parts of Asia, are still usually called tiles. Roof shingles may deteriorate faster and need to repel more water than wall shingles. They are a very common roofing material in the United States.
Roof pitch is the steepness of a roof expressed as a ratio of inch(es) rise per horizontal foot, or as the angle in degrees its surface deviates from the horizontal. A flat roof has a pitch of zero in either instance; all other roofs are pitched.
Portal frame is a construction technique where vertical supports are connected to horizontal beams or trusses via fixed joints with designed-in moment-resisting capacity. The result is wide spans and open floors.
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.
A stepped gable, crow-stepped gable, or corbie step is a stairstep type of design at the top of the triangular gable-end of a building. The top of the parapet wall projects above the roofline and the top of the brick or stone wall is stacked in a step pattern above the roof as a decoration and as a convenient way to finish the brick courses. A stepped parapet may appear on building facades with or without gable ends, and even upon a false front.
A rain gutter, eavestrough, eaves-shoot or surface water collection channel is a component of a water discharge system for a building. It is necessary to prevent water dripping or flowing off roofs in an uncontrolled manner for several reasons: to prevent it damaging the walls, drenching persons standing below or entering the building, and to direct the water to a suitable disposal site where it will not damage the foundations of the building. In the case of a flat roof, removal of water is essential to prevent water ingress and to prevent a build-up of excessive weight.
A Dutch gable roof or gablet roof is a roof with a small gable at the top of a hip roof. The term Dutch gable is also used to mean a gable with parapets. Some sources refer to this as a gable-on-hip roof.
A gable roof is a roof consisting of two sections whose upper horizontal edges meet to form its ridge. The most common roof shape in cold or temperate climates, it is constructed of rafters, roof trusses or purlins. The pitch of a gable roof can vary greatly.
In construction, covering is the exterior layer of a building's roof. The covering ensures waterproofing by directing and collecting rainwater. It also provides mechanical protection against various external elements such as dust and intrusions. Additionally, it must withstand static mechanical pressures from snow and dynamic forces from strong winds.
