A door is a generally floor-length opening in a wall (or other partition), often equipped with a hinged or sliding panel which can be moved to leave the opening accessible, or to close it more or less securely. Doors are nearly universal in structures of all kinds (especially houses and other buildings), allowing passage between inside and outside, or among internal rooms. Doors are also found in vehicles, cupboards, cages, etc.

The purpose of a door opening is:

• to allow people, animals and objects to pass
• for ventilation

The purpose of a door closure is:

• preventing passage of air; reducing air drafts and creating an enclosed space that can be heated or cooled more effectively (revolving doors are especially efficient for this purpose)
• privacy and noise reduction
• keeping occupants inside a vehicle
• regulation of access, especially when combined with various types of locks
• for aesthetics (e.g. cupboard doors cutting off view of the contents)
• to help prevent the spread of fire

Doors and doorways can also appear in metaphorical or mystical situations; for example, a spiritualist might speak of "opening a door to the other world". Doors can have ritual purposes (one example concerns the doorkeeping duties of the Gentleman Usher of the Black Rod).

The term door can refer either to the opening or to the movable panel which closes it. The term doorway can be used to refer specifically to the opening. When framed in wood for snug fitting of a door, the doorway consists of two vertical jambs on either side, a lintel or head jamb at the top, and perhaps a threshold at the bottom.

See door furniture for a discussion of attachments to doors such as doorhandles and doorknobs.

Types of doors

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A door may slide or rotate. Sometimes a door, though not just sliding, stays parallel to the wall while opening and closing.

Sliding is usually horizontal. In opened position the door may be exposed on one side; a person leaning on that side when the door is closed, can be hurt when the door is opened. Also an object can obstruct the door. Sometimes the door is constructed such that in closed state the sliding door forms a smooth continuation of the wall, e.g. in the case of a sliding side door of a vehicle.

The door may also slide between two panels (pocket door).

In the case of rotation, the axis of rotation is usually vertical, but e.g. for garage doors often horizontal, above the door opening. Sometimes the axis of rotation is, with a special construction, not in the plane of the door, on the other side than that in which the door opens, to reduce the space required on the side to which the door opens. This is sometimes the case in a train, for the door to the toilet, opening inward.

Many kinds of doors have specific names, depending on their purpose. The most common variety of door consists of a single rigid panel that fills the doorway, hinged along one side so that it can fold away from the doorway in one direction but not in the other. Many variations on this basic design are possible, such as "double" doors that have two adjacent independent panels hinged on each side of the doorway.

A trapdoor is a door that is oriented horizontally in a floor or ceiling, often accessed via a ladder.

A stable door is divided in half horizontally. The top half can be opened to allow the horse to be fed, while the bottom half can be closed to keep the animal inside. Stable doors are also known as dutch doors.

A swing door has special hinges that allow it to open either outwards or inwards, and is usually sprung to keep it closed. Saloon doors are a pair of lightweight swing doors often found in public bars.

A blind door is a door with no passage, a 'fake' door that is actually part of the wall. It is used for decorative purposes.

An up-and-over door is often used in garages. Instead of hinges it has a mechanism, often counterbalanced or sprung, that allows it to be lifted so that it rests horizontally above the opening. Also known as an overhead door.

A barn door is a door on a barn. It is often/always found on barns, and because of a barn's immense size (often) doors are subsequently big for utility.

A French door is a door that has multiple lights, the full length of the door. Traditional French doors are assembled from individual small pieces of glass and mullions. French doors made of double-pane glass (on exterior doors for insulation reasons) may have the decorative grill embedded between the panes. The decorative grill may also be superimposed on top of single pane of glass in the door.

A louvre door has fixed or movable wooden fins (often called slats) which permit open ventilation whilst preserving privacy and preventing the passage of light to the interior. Being relatively weak structures, they are most commonly used for wardrobes and drying rooms, where security is of less importance than good ventilation, although a very similar structure is commonly used to form window shutters.

A flush door is a completely smooth, panelled door, having plywood or MDF fixed over a light timber frame, the hollow parts of which are often filled with a cardboard core material. Flush doors are most commonly employed in the interior of a dwelling, although slightly more substantial versions are occasionally used as exterior doors, especially within hotels and other buildings containing many independent dwellings.

A ledge and brace door is a door made from multiple vertical planks fixed together by two horizontal planks (the ledges) and kept square by a diagonal plank (the brace).

A garden door is any door that opens to a garden or backyard. It is often used specifically for double French doors in place of a sliding glass door. In such a configuration, it has the advantage of a very large opening for moving large objects in and out.

A pet door is an opening in a door to allow pets to enter and exit without the main door being opened. It may be simply covered by a rubber flap or it may be an actual door hinged on the top that the pet can push through. Pet doors may be mounted in a sliding glass door as a new (permanent or temporary) panel. Pet doors may be unidirectional, only allowing pets to exit. Pet doors may be electronic, only allowing pets with a special electronic tag to enter.

A pocket door is a door that slides on rails, rather than swinging on hinges, and, when opened, slides into an open cavity within a wall.

A sliding glass door is a door made of glass that slides open and sometimes has a screen. Sliding glass doors are common in many houses, particularly as an entrance to the backyard. Such doors are also popular for use for the entrances to commercial structures.

A revolving door is a type of door that typically consists of a structure with three or four panels that meet in the center and rotate one way about a vertical axis (sometimes the movement is not in a circle, but following a more complicated path, a combination of rotation and translation). Between the point of access and the point of exit the user walks between two moving panels. The door may be motorized or the user needs to push the front panel, and the space between two panels may be designed for multiple users or a single one. This door design is used primarily to maintain an air seal from the outside, thus minimizing leaking of climate controlled air from the building and the resulting expense of compensating for the loss. This type of door is also often seen as a mark of prestige and glamour for a building and it not unusual for neighbouring buildings to install their own revolving doors when a rival building gets one.

Automatic doors are powered open and closed, a door fitted with a spring to close it is not an automatic door. There are three methods by which an automatic door is activated.

1 - A sensor detects traffic is approaching. Sensors for automatic doors are generally:

• A pressure sensor - a floor mat which reacts to the pressure of someone standing on it.
• An infra-red curtain or beam which shines invisible light onto sensors; if someone or something blocks the beam the door can open.
• A motion sensor which uses low-power microwave radar.
• An electronic sensor (e.g. based on infra red or radio waves) can be triggered by something that someone carries, or is installed inside a vehicle. These are popular for garage doors.

2 - A switch is operated manualy, perhaps after security checks. This can be a push button switch or a swipe card.

3 - The user pushes, or pulls the door, once the door detects the movement it completes the open and close cycle. These are also known as power-assisted doors.

In addition to activate sensors automatic doors are generally fitted with safety sensors. These are usually an infra-red curtain or beam, but can be a pressure mat fitted on the swing side of the door. The purpose of the safety sensor is to prevent the door opening or slow its speed if an object is detected in its path whilst opening and to prevent the door closing or reactivate it if an object is detected in its path whilst closing.

Heron of Alexandria created the first automatic door.

Blast-proof doors, nuclear-blast proof doors, etc.

A tambour door is made of narrow horizontal slats and rolls up and down along vertical tracks and is typically found in entertainment centres and cabinets.

Door components and construction

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Door frames:

• Lintel - A horizontal beam above a door that supports the wall above it. (Also known as a header)
• Jambs - The vertical posts that form the sides of a door frame, where the hinges are mounted, and with which the bolt interacts.
• Sill - A horizontal beam below the door that supports the frame
• Doorstop - a thin slat built inside the frame to prevent a door from swinging through when closed, which might break the hinges.
• Architrave - The decorative molding that outlines a door frame. (called an Archivolt if the door is arched). Called door casing or brickmold in North America.

Related hardware:

• Handles:
  • Doorknob - A knob or lever on an axle that is rotated to release the bolt.
  • Door Handle - A fixed handle, usually accompanied with a latch to release the bolt, on some doors (such as car doors) the latch is incorporated into a hinged handle that releases when pulled on. A handleset is composed of the exterior handle (including escutcheon), an independent deadbolt, and the interior package (knob or lever)
  • Crash bar - A spring-loaded bar that is mounted horizontally on the side of the door that swings outward. When pushed upon, the bolt is released. This device is mandatory in most fire exits. Many of these doors are one-way, and cannot be opened from the outside. To use this device on a two-way door, another type of handle must be mounted on the inward swinging side. (Also known as a "panic bar" or "cross-bar")
• Fasteners:
  • Latch - A device that allows one to fasten a door, but doesn't necessarily require an external handle
  • Lock - A device that prevents access those without a key or combination.
  • Bolt - A (nearly always) metal shaft usually internal to the door that extends into the jamb to fasten a door.
  • Latchbolt - A bolt that has an angled surface which acts as a ramp to push the bolt in while the door is being closed. By the use of a latchbolt, a door can be closed without having to operate the handle.
  • Deadbolt - Deadbolts usually extend deeper into the frame and are not automatically retractable the way latchbolts are. They are typically manipulated with a lock on the outside and either a lock or a latch on the inside. Deadbolts are generally used for security purposes on external doors.
  • Strike - A plate with a hole in the middle made to receive a bolt. If the strike is for a latchbolt, it typically also includes a small ramped area to help the bolt move inward while the door is being closed.
  • Crossbar - A historically common, but now obsolete and overly primitive fastener consisting simply of a plank or beam mounted to one side of a door by a set of cleats. The board can be slid past the frame to block the door. Alternatively, the bar can be a separate piece that is placed into open cleats or hooks, extending across the frame on both sides. On a set of double doors, the same principle works, but needn't extend past the frame. The bar simply extends into another set of cleats on the other door such as to interfere with the door opening. Note that this device is essentially the opposite of the crash bar (see above), in that it effectively makes the door one-way when in use. (Also known as a bolt note the polysemy with bolt and cross bar above)
• Hinge - A component that attaches one edge of a door to the frame, while allowing the other edge to swing from it. It usually consists of a pair of plates, each with a set of open cylindrical rings (the knuckles) attached to them. The knuckles of the two plates are offset from each other and mesh together. A hinge pin is then placed through the two sets of knuckles and usually fixed, to combine the plates and make the hinge a single unit. One door usually has about three hinges, but it can vary.

Panel Doors (A door built with Frame and panel construction):

• Stiles - Vertical boards that run the full height of a door and compose its right and left edges. The hinges are mounted to the fixed side (known as the "hanging stile"), and the handle, lock, bolt, and/or latch are mounted on the swinging side (known as the "latch stile").
• Rails - Horizontal boards at the top, bottom, and optionally in the middle of a door that joins the two stiles and split the door into two or more rows of panels. The "top rail" and "bottom rail" are named for their positions. The bottom rail is also known as "kick rail". A middle rail at the height of the bolt is known as the "lock rail", other middle rails are commonly known as "cross rails".
• Mullions - Smaller optional vertical boards that run between two rails, and split the door into two or more columns of panels.
• Panels - Large, wider boards used to fill the space between the stiles, rails, and mullions. The panels typically fit into grooves in the other pieces, and help to keep the door rigid.
• Lites - Pieces of glass used in place of a panel, essentially giving the door a window. (also known as a "lights")

Plank & Batten Doors (An older design consisting primarily of vertical slats):

• Planks - Vertical boards that extend the full height of the door, and are placed side by side filling the door's width.
• Battens - Smaller slats that extend horizontally across the door which the planks are affixed to. The battens hold the planks together. Sometimes a long diagonal slat or two are also implemented to prevent the door from skewing. On some doors, especially antique ones, the battens are replaced with iron bars that are often built into the hinges as extensions of the door-side plates.

Flush Doors (many modern doors, including most interior doors):

• Stiles and Rails - As above, but usually smaller. They form the outside edges of the door.
• Core material: Material within the door used simply to fill space, provide rigidity and reduce druminess.
  • Hollow-Core - Often consists of a Lattice or Honeycomb made of corrugated cardboard, or thin wooden slats. Can also be built with staggered wooden blocks. Hollow-core flush doors are commonly used as interior doors.
    • Lock block - A solid block of wood mounted within a hollow-core flush door near the bolt to provide a solid and stable location for mounting the door's hardware.
  • Stave-Core - Consists of wooden slats stacked upon one another in a manner similar to a plank & batten door (though the slats are usually thinner) or the wooden-block hollow-core (except that the space is entirely filled).
  • Solid-Core - Can consist of low-density Particle board or Foam used to completely fill the space within the door. Solid-core flush doors (especially foam-core ones) are commonly used as exterior doors because they provide more insulation and strength.
• Skin - The front and back faces of the door are then covered with wood veneer, thin plywood, sheet metal, fiberglass, or vinyl. The wooden materials are usually layered with the grain alternating direction between layers to prevent warping. The skin of a flush door is sometimes molded (in the case of metal, fiberglass, or vinyl), or molding can be added (to wood) to give the appearance of a panel door, though the construction underneath differs greatly.

Door Swings

Door swings, or Handing, are always determined from the outside (ie. outside to inside, or public to private).

• Left Hand (LH): If the hinges are on the left and the door opens in, it's a left hand door. You push the door with your left hand.

• Right Hand (RH): If the hinges are on the right and the door opens in, it's a right hand door. You push the door with your right hand.

• Left Hand Reverse (LHR): If the hinges are on the left and the door opens out, it's a left hand reverse door. You pull the door with your left hand.

• Right Hand Reverse (RHR): If the hinges are on the right and the door opens out, it's a right hand reverse door. You pull the door with your right hand.

Another way to determine door "handing" is to imagine yourself standing in the doorway with your back against the hinges. Swing your right or left arm in the way that the door swings. If you swing your left arm then the door is left handed. Swing your right arm and it is right handed. This method does not require a reference such as "from the outside" or "from the inside".

History

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The earliest records are those represented in the paintings of the Egyptian tombs, in which they are shown as single or double doors, each in a single piece of wood. In Egypt, where the climate is intensely dry, there would be no fear of their warping, but in other countries it would be necessary to frame them, which according to Vitruvius (iv. 6.) was done with stiles (sea/si) and rails (see: Frame and panel): the spaces enclosed being filled with panels (tympana) let into grooves made in the stiles and rails. The stiles were the vertical boards, one of which, tenoned or hinged, is known as the hanging stile, the other as the middle or meeting stile. The horizontal cross pieces are the top rail, bottom rail, and middle or intermediate rails. The most ancient doors were in timber, those made for King Solomon's temple being in olive wood (I Kings vi. 31-35), which were carved and overlaid with gold. The doors dwelt upon in Homer would appear to have been cased in silver or brass. Besides Olive wood, elm, cedar, oak and cypress were used.

All ancient doors were hung by pivots at the top and bottom of the hanging stile which worked in sockets in the lintel and sill, the latter being always in some hard stone such as basalt or granite. Those found at Nippur by Dr. Hilprecht, dating from 2000 B.C. were in dolerite. The tenons of the gates at Balawat were sheathed with bronze (now in the British Museum). These doors or gates were hung in two leaves, each about 8 ft.4 in. wide and 27 ft. high; they were encased with bronze bands or strips, 10 in. high, covered with repouss decoration of figures, etc. The wood doors would seem to have been about 3 in. thick, but the hanging stile was over 14 inches diameter. Other sheathings of various sizes in bronze have been found, which proves this to have been the universal method adopted to protect the wood pivots. In the Hauran in Syria, where timber is scarce the doors were made in stone, and one measuring 5 ft. 4 in. by 2 ft. 7 in. is in the British Museum; the band on the meeting stile shows that it was one of the leaves of a double door. At Kuffeir near Bostra in Syria, Burckhardt found stone doors, 9 to 10 ft. high, being the entrance doors of the town. In Etruria many stone doors are referred to by Dennis.

The ancient Greek and Roman doors were either single doors , double doors or folding doors, in the last case the leaves were hinged and folded back. In Eumachia, is a painting of a door with three leaves. In the tomb of Theron at Agrigentum there is a single four-panel door carved in stone. In the Blundell collection is a bas-relief of a temple with double doors, each leaf with five panels. Among existing examples, the bronze doors in the church of SS. Cosmas and Damiano, in Rome, are important examples of Roman metal work of the best period; they are in two leaves, each with two panels, and are framed in bronze. Those of the Pantheon are similar in design, with narrow horizontal panels in addition, at the top, bottom and middle. Two other bronze doors of the Roman period are in the Lateran Basilica.

The doors of the church of the Nativity at Bethlehem (6th century) are covered with plates of bronze, cut out in patterns: those of Hagia Sophia at Constantinople, of the 8th and 9th century, are wrought in bronze, and the west doors of the cathedral of Aix-la-Chapelle (9th century), of similar manufacture, were probably brought from Constantinople, as also some of those in St. Marks, Venice.

Of the 11th and 12th centuries there are numerous examples of bronze doors, the earliest being one at Hildesheim, Germany (1015). Of others in South Italy and Sicily, the following are the finest: in Sant Andrea, Amalfi (1060); Salerno (1099); Canosa (1111); Troia, two doors (1119 and 1124); Ravello (1179), by Barisano of Trani, who also made doors for Trani cathedral; and in Monreale and Pisa cathedrals, by Bonano of Pisa. In all these cases the hanging stile had pivots at the top and bottom. The exact period when the hinge was substituted is not quite known, but the change apparently brought about another method of strengthening and decorating doors, viz, with wrought-iron bands of infinite varieties of design. As a rule three bands from which the ornamental work springs constitute the hinges, which have rings outside the hanging stiles fitting on to vertical tenons run into the masonry or wooden frame. There is an early example of the 12th century in Lincoln; in France the metal work of the doors of Notre Dame at Paris is perhaps the most beautiful in execution, but examples are endless throughout France and England.

Returning to Italy, the most celebrated doors are those of the Battistero di San Giovanni (Florence), which together with the door frames are all in bronze, the borders of the latter being perhaps the most remarkable: the modeling of the figures, birds and foliage of the south doorway, by Andrea Pisano (1330), and of the east doorway by Ghiberti (1425-1452), are of great beauty; in the north door (1402-1424) Ghiberti adopted the same scheme of design for the paneling and figure subjects in them as Andrea Pisano, but in the east door the rectangular panels are all filled, with bas-reliefs, in which Scripture subjects are illustrated with innumerable figures, these being probably the gates of Paradise of which Michelangelo speaks.

The doors of the mosques in Cairo were of two kinds; those which, externally, were cased with sheets of bronze or iron, cut out in decorative patterns, and incised or inlaid, with bosses in relief; and those in wood, which were framed with interlaced designs of the square and diamond, this latter description of work being Coptic in its origin. The doors of the palace at Palermo, which were made by Saracenic workmen for the Normans, are fine examples and in good preservation. A somewhat similar decorative class of door to these latter is found in Verona, where the edges of the stiles and rails are beveled and notched.

In the Renaissance period the Italian doors are quite simple, their architects trusting more to the doorways for effect; but in France and Germany the contrary is the case, the doors being elaborately carved, especially in the Louis XIV and Louis XV periods, and sometimes with architectural features such as columns and entablatures with pediment and niches, the doorway being in plain masonry. While in Italy the tendency was to give scale by increasing the number of panels, in France the contrary seems to have been the rule; and one of the great doors at Fontainebleau, which is in two leaves, is entirely carried out as if consisting of one great panel only.

The earliest Renaissance doors in France are those of the cathedral of St. Sauveur at Aix (1503); in the lower panels there are figures 3 ft. high in Gothic niches, and in the upper panels a double range of niches with figures about 2 ft. high with canopies over them, all carved in cedar. The south door of Beauvais cathedral is in some respects the finest in France; the upper panels are carved in high relief with figure subjects and canopies over them. The doors of the church at Gisors (1575) are carved with figures in niches subdivided by classic pilasters superimposed. In St. Maclou at Rouen are three magnificently carved doors; those by Jean Goujon have figures in niches on each side, and others in a group of great beauty in the center. The other doors, probably about forty to fifty years later, are enriched with bas-reliefs, landscapes, figures and elaborate interlaced borders.

In England in the 17th century the door panels were raised with bolection or projecting moldings, sometimes richly carved, round them; in the 18th century the moldings worked on the stiles and rails were carved with the egg and tongue ornament.

• The oldest door in England can be found in Westminster Abbey and dates from 1050. ^*

See also

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• Door safety
• "Suicide door"
• Janus, Roman god of doors

External links

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Patents

• US 2,724,258 -- Fire exit lock
• Historic Doors - Glossary
• Famous door website

Architectural elements | Doors

Porta | Dveře | Tür | Pordo | در | Porta | Pintu | דלת | Deur | Deure | 扉 | Dør | Porte | Drzwi | Porta | Дверь | Door | Dvere | Ovi | Dörr | 门 (建筑)