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{{short description|Vertical structure, usually solid, that defines and sometimes protects an area}}
{{Other uses}}
{{pp-semi-indef}}
{{multiple image|perrow=2|total_width=300|image1=Noel_2005_Pékin_031_muraille_de_chine_Mutianyu.jpg|width1=300|height1=|image2=J.L. Gerome - The Wailing Wall - Google Art Project.jpg|width2=300|height2=|image3=Hadrian%27s_wall_at_Greenhead_Lough.jpg|width3=300|height3=|image4=City walls with the town and the salt mines in the background, Ston, Croatia (PPL3-Altered) julesvernex2.jpg|width4=300|height4=|footer=[[Great Wall of China]], [[Western Wall]],<br>
[[Hadrian's Wall]], [[Walls of Ston]]}}

A '''wall''' is a [[structure]] and a surface that defines an area; carries a load; provides [[security]], [[Shelter in place|shelter]], or [[soundproofing]]; or serves a decorative purpose. There are various types of walls, including [[border barrier]]s between countries, brick walls, [[defensive wall]]s in [[fortification]]s, and [[retaining wall]]s that hold back dirt, stone, water, or noise. Walls can also be found in buildings, where they support [[Roof|roofs]], [[Floor|floors]], and [[Ceiling|ceilings]], enclose spaces, and provide shelter and security.

The construction of walls can be categorized into [[Framing (construction)|framed walls]] and mass-walls. Framed walls transfer the load to the [[Foundation (engineering)|foundation]] through [[Post (structural)|posts]], [[Column|columns]], or [[Wall stud|studs]] and typically consist of structural elements, [[Thermal insulation|insulation]], and finish elements. Mass-walls are made of solid materials such as [[masonry]], [[concrete]], [[adobe]], or [[rammed earth]]. Walls may also house utilities like [[electrical wiring]] or [[plumbing]] and must conform to local [[Building code|building]] and [[fire code]]s.

Walls have historically served defensive purposes, with the term "wall" originally referring to [[defensive wall]]s and ramparts. Examples of famous defensive walls include the [[Great Wall of China]] and [[Hadrian's Wall]]. In addition to their functional roles, walls can also be decorative, contributing to the [[Aesthetics|aesthetic]] appeal of a space.

==Etymology==
[[File:Beowulf - weall.jpg|thumb|"weall," an [[Old English]] word for 'wall']]

The term ''wall'' comes from the [[Latin]] {{Lang|la|vallum}} meaning "an earthen wall or [[Rampart (fortification)|rampart]] set with [[palisade]]s, a row or line of stakes, a wall, a rampart, fortification", while the Latin word {{Lang|la|murus}} refers to a defensive stone wall.<ref>"Wall". Whitney, William Dwight, and Benjamin E. Smith. ''The Century dictionary and cyclopedia'', vol. 8. New York: Century Co., 1901. 6,809. Print.</ref> [[English language|English]] uses the same word to mean an external wall and the internal sides of a [[room]], but this is not universal, and many languages distinguish between the two. This distinction can be seen In [[German language|German]] between {{Lang|de|wand}} and {{Lang|de|mauer}}, and in [[Spanish language|Spanish]] between {{Lang|es|pared}} and {{Lang|es|muro}}.

==Defensive wall==
{{main|Defensive wall}}
The word wall originally referred to defensive walls and [[Rampart (fortification)|ramparts]].

==Building wall==
{{See also|American historic carpentry}}
The purposes of walls in buildings are to support [[roof]]s, [[floor]]s and [[ceiling]]s; to enclose a space as part of the [[building envelope]] along with a roof to give buildings form; and to provide shelter and security. In addition, the wall may house various types of utilities such as [[electrical wiring]] or [[plumbing]]. Walls may or may not be [[Load-bearing wall|load-bearing]]. Walls are required to conform to the local [[Building code|building]] and/or [[Fire code|fire codes]].

Wall construction falls into two basic categories: ''framed walls'' or ''mass-walls''. In [[Framing (construction)|framed walls]], the load is transferred to the foundation through posts, columns or studs. Framed walls most often have three or more separate components: the structural elements (such as 2×4 studs in a house wall), [[Thermal insulation|insulation]], and finish elements or surfaces (such as [[drywall]] or [[panelling]]). Mass-walls are of a solid material, such as [[masonry]], [[concrete]] including [[slipform stonemasonry]], [[log building]], [[cordwood construction]], [[adobe]], [[rammed earth]], [[Cob (material)|cob]], [[earthbag construction]], [[Bottle wall|bottles]], [[tin can wall|tin cans]], [[straw-bale construction]], or [[Ice palace|ice]].

There are three basic methods through which walls control water intrusion: moisture storage, drained [[Cladding (construction)|cladding]], or face-sealed cladding.<ref>Committee on Damp Indoor Spaces and Health, Board on Health Promotion and Disease Prevention. ''Damp indoor spaces and health''. Institute of Medicine, (U. S.). National Academies Press. Washington, D. C.. 2004. 34-35. Print.</ref> Moisture storage is typical of stone and brick ''mass-wall'' buildings where moisture is absorbed and released by the walls of the structure itself. ''Drained cladding'', also known as ''screened walls,''<ref name="ASTM">Straube, J. F.and Burnett, E. F. P., "Driving Rain and Masonry Veneer". ''Water Leakage through Building Facades, ASTM STP 1314''. R. J. Kudder and J. L. Erdly, Eds. American Society for Testing and Materials (ASTM), 1998. 75. Print.</ref> acknowledges moisture will penetrate the cladding so a ''moisture barrier'' such as [[housewrap]] or [[felt paper]] inside the cladding provides a second line of defense, and sometimes a ''drainage plane'' or ''air gap'' allows a path for the moisture to drain down through and exit the wall. Sometimes [[Ventilation (architecture)|ventilation]] is provided in addition to the drainage plane such as in [[rainscreen]] construction. ''Face-sealed'' cladding, also called ''barrier wall'' or ''perfect barrier'' cladding,<ref name="ASTM" /> relies on maintaining a [[leak]]-free surface of the cladding. Examples of face sealed cladding are the early [[exterior insulation finishing system]]s, structural glazing, metal clad panels, and [[Corrugated galvanised iron|corrugated metal]].

Building walls frequently become works of art, externally and internally, such as when featuring [[mosaic]] work or when [[mural]]s are painted on them; or as design foci when they exhibit [[Surface finish|textures or painted finishes]] for effect.

===Curtain wall===
{{Main|Curtain wall (architecture)}}
[[File:Pest-budai vaktérkép (Baróthy Anna, 2016), Széll Kálmán tér, Budapest.jpg|thumb|Wall art in [[Budapest]]'s [[Széll Kálmán tér|Széll Kálmán Square]]<ref>{{Cite web |url=http://www.landezine.com/index.php/2016/10/szell-kalman-square-budapest-hungary/ |title=Széll Kálmán square, Budapest, Hungary « Landscape Architecture Works |website=Landezine |last=Baróthy |first=Anna |date=2016 |language=en-US |archive-url=https://web.archive.org/web/20180207183939/http://www.landezine.com/index.php/2016/10/szell-kalman-square-budapest-hungary/ |archive-date=2018-02-07 |access-date=2018-02-07}}</ref>]]
[[File:Münster, LVM -- 2017 -- 9343-7.jpg|thumb|Glass [[curtain wall (architecture)|curtain wall]]s on a contemporary German skyscraper]]
In [[architecture]] and [[civil engineering]], curtain wall refers to a building [[facade]] that is not [[load-bearing wall|load-bearing]] but provides decoration, finish, front, face, or historical preservation.

===Precast wall===
[[Precast concrete|Precast walls]] are walls which have been manufactured in a [[factory]] and then shipped to where it is needed, ready to install. Compared to walls made of other materials, such as brick, it is faster to install and may have a lower [[cost]].

===Mullion wall===
{{main|Mullion wall}}
Mullion walls are a structural system that carries the load of the floor slab on [[Prefabrication|prefabricated]] panels around the perimeter.

===Partition wall===
[[File:Glass Partition Wall.jpg|thumb|Glass partition walls]]
A partition wall is a usually thin wall that is used to separate or divide a [[room]], primarily a pre-existing one. Partition walls are usually not [[Load-bearing wall|load-bearing]], and can be constructed out of many materials, including steel panels, bricks, cloth, [[plastic]], [[Drywall|plasterboard]], [[wood]], blocks of [[clay]], [[terracotta]], [[Concrete masonry unit|concrete]], and [[glass]] (such as [[sheet glass]]).

Glass partition walls are a series of individual [[toughened glass]] panels mounted in wood or metal framing. They may be suspended from or slide along a robust [[aluminium]] ceiling track.<ref>{{cite web|title=PARTITION WALL|url=http://niceduniya.blogspot.com/2007/12/partition-wall.html|publisher=Principles of Design|access-date=17 July 2013|archive-date=24 September 2018|archive-url=https://web.archive.org/web/20180924190304/http://niceduniya.blogspot.com/2007/12/partition-wall.html|url-status=dead}}</ref> The system does not require the use of a floor guide, which allows easy operation and an uninterrupted threshold.

A timber partition consists of a wooden framework, supported on the floor or by side walls. Metal [[lath]] and plaster, properly laid, forms a reinforced partition wall. Partition walls constructed from [[fibre cement]] backer board are popular as bases for [[Tile|tiling]] in kitchens or in wet areas like bathrooms. Galvanized sheet fixed to wooden or steel members are mostly adopted in works of temporary character. Plain or reinforced partition walls may also be constructed from concrete, including pre-cast concrete blocks. Metal framed partitioning is also available. This partition consists of track (used primarily at the base and head of the partition) and studs (vertical sections fixed into the track typically spaced at {{convert|24|,|16|,|12|in|cm|-1|abbr=out|disp=or}}).

Internal wall partitions, .also known as [[Office partition|office partitioning]], are usually made of [[Drywall|plasterboard]] ([[drywall]]) or varieties of glass. [[Tempered glass|Toughened glass]] is a common option, as [[low-iron glass]] (better known as ''opti-white glass'') increases light and solar heat transmission.

Wall partitions are constructed using beads and tracking that is either hung from the ceiling or fixed into the ground.<ref>{{cite web|title=Partition Walls|url=http://www.ceilingspartitions.co.uk/partitions-walls/partitions/|publisher=Excellence in craftsmanship|access-date=17 July 2013}}</ref> The panels are inserted into the tracking and fixed. Some wall partition variations specify their fire resistance and acoustic performance rating.

;Movable partitions
{{main|Portable partition}}
Movable partitions are walls that open to join two or more rooms into one large floor area. These include:
* Sliding—a series of panels that slide in tracks fixed to the floor and ceiling, similar sliding doors.
* [[Sliding door|Sliding]] and [[Folding door|folding]] doors—similar to sliding folding doors, these are good for smaller spans.
* Folding partition walls–a series of interlocking panels suspended from an overhead track that when extended provide an acoustical separation, and when retracted stack against a wall, ceiling, closet, or ceiling pocket.
* Screens—usually constructed of a metal or [[Timber framing|timber frame]] fixed with [[plywood]] and [[Particle board|chipboard]] and supported with legs for free standing and easy movement.
* [[Pipe and drape]]—fixed or telescopic uprights and horizontals provide a ground supported drape system with removable panels.

===Party wall===
{{main|Party wall}}

Party walls are walls that separate buildings or units within a building. They provide fire resistance and [[Soundproofing|sound resistance]] between occupants in a building. The minimum fire resistance and sound resistance required for the party wall is determined by a building code and may be modified to suit a variety of situations. Ownership of such walls can become a legal issue. It is not a load-bearing wall and may be owned by different people.

===Infill wall===
{{main|Infill wall}}

An infill wall is the supported wall that closes the perimeter of a building constructed with a three-dimensional framework structure.

===Fire wall===
{{main|Firewall (construction)}}
{{distinguish|Firewall (computing)}}

Fire walls resist spread of fire within or between structures to provide [[passive fire protection]]. A delay in the spread of fire gives occupants more time to escape and [[Firefighter|fire fighters]] more time to extinguish the fire. Some fire walls allow fire resistive window assemblies,<ref>{{cite book |title=NFPA 221 Standard for high Challenge Fire Walls, Fire Walls, and Fire Barrier Walls |at=Table 4.9.2 |edition=2021}}</ref> and are made of [[Combustibility and flammability|non-combustible]] material such as concrete, cement block, brick, or fire rated drywall. Wall penetrations are [[Hermetic seal|sealed]] with fire resistive materials. A doorway in a firewall must have a rated [[fire door]]. Fire walls provide varying resistance to the spread of fire, (one to four hours). Firewalls can also act as smoke barriers when constructed vertically from slab to roof deck and horizontally from an exterior wall to exterior wall subdividing a building into sections.

===Shear wall===
{{main|Shear wall}}
Shear walls resist lateral forces such as in an earthquake or severe wind. There are different kinds of shear walls such as the [[steel plate shear wall]].

===Knee wall===
{{main|Knee wall}}
Knee walls are short walls that either support [[Rafter|rafters]] or add height in the top floor rooms of houses. In a {{frac|1|1|2}}-story house, the knee wall supports the ''half story''.

===Cavity wall===
{{main|Cavity wall}}
Cavity walls are walls made with a space between two "skins" to inhibit heat transfer.

===Pony wall===
[[Pony wall]] (or dwarf wall) is a general term for short walls, such as:
* A half wall that only extends partway from floor to ceiling, without supporting anything
* A stem wall—a concrete wall that extends from the foundation slab to the cripple wall or floor joists
* A cripple wall—a framed wall from the stem wall or foundation slab to the floor joists

===Demountable wall===
[[Image:214_King_-_demountable_walls_and_doors_(5277760889).jpg|thumb|Demountable wall and door in an office building]]
[[Demountable|Demountable walls]] fall into 3 different main types:
*Glass walls (unitesed panels or [[butt joint]]),
*Laminated [[particle board]] walls (this may also include other finishes, such as whiteboards, [[cork board]], magnetic, etc., typically all on purpose-made [[wall stud]]s)
*[[Drywall]]

===Solar energy===
{{main|Trombe wall}}
{{See also|Double-skin facade}}
A trombe wall in [[passive solar building design]] acts as a [[heat sink]].

==Shipbuilding==
{{main|Shipbuilding}}
On a ship, a wall that separates major compartments is called a ''[[Bulkhead (partition)|bulkhead]]''. A thinner wall between [[Cabin (ship)|cabins]] is called a ''partition''.

==Boundary wall==
[[File:Stone wall.jpg|thumb|Stone wall of an English barn]][[File:Wall intersection.jpg|thumb|A red bricks boundary wall intersection]]
Boundary walls include privacy walls, boundary-marking walls on property, and [[town walls]]. These intergrade into [[fence]]s. The conventional differentiation is that a fence is of minimal thickness and often open in nature, while a wall is usually more than a nominal thickness and is completely closed, or opaque. More to the point, an exterior structure of wood or wire is generally called a [[fence]]—but one of [[masonry]] is a wall. A common term for both is [[border barrier|barrier]], which is convenient for structures that are partly wall and partly fence—for example the [[Berlin Wall]]. Another kind of wall-fence ambiguity is the [[ha-ha]]—which is set below ground level to protect a view, yet acts as a barrier (to cattle, for example).

[[File:Olditalianwall.JPG|thumb|left|upright|An old Italian wall surrounded by flowers]]
Before the invention of [[artillery]], many of the world's [[city|cities]] and towns, particularly in Europe and Asia, had [[defensive wall|defensive or protective walls]] (also called town walls or city walls). In fact, the English word "wall" derives from Latin ''[[vallum]]''—a type of fortification wall. These walls are no longer relevant for defense, so such cities have grown beyond their walls, and many fortification walls, or portions of them, have been torn down—for example in [[Rome]], [[Italy]] and [[Beijing]], [[China]]. Examples of protective walls on a much larger scale include the [[Great Wall of China]] and [[Hadrian's Wall]].

==Border wall==
{{Main|Border barrier}}
[[File:Berliner Mauer, ostdeutscher Grenzer beobachtet Räumung des Kubat-Dreieck.jpg|thumb|Berlin wall, July 1, 1988]]
[[File:Algodones sand-dune-fence.jpg|thumb|[[Mexico–United States barrier]] in California]]
Some walls formally mark the border between one population and another. A [[border wall]] is constructed to limit the movement of people across a certain line or [[border]]. These structures vary in placement with regard to international borders and [[topography]]. The most famous example of border barrier in history is probably the [[Great Wall of China]], a series of walls that separated the Empire of [[China]] from nomadic powers to the north. The most prominent recent example is the [[Berlin Wall]], which surrounded the [[enclave]] of [[West Berlin]] and separated it from [[East Germany]] for most of the [[Cold War]] era. The US-Mexico border wall, separating the United States and Mexico, is another recent example.

==Retaining wall==
{{main|Retaining wall}}
[[File:Dry Stone Wall - Blackmile Lane, Grendon, Northamptonshire.jpg|thumb|right
|[[Dry-stone wall]], Grendon]]
[[File:Perfectwall.jpg|thumb|upright|[[Ashlar]] wall: Inca wall at [[Machu Picchu]], [[Peru]]]]
[[File:Western side of the Great Mosque of Kairouan.jpg|thumb|right|View of the western enclosing wall of the [[Mosque of Uqba|Great Mosque of Kairouan]] (also called the Mosque of Uqba) in the city of [[Kairouan]] in [[Tunisia]].]]
In areas of rocky soils around the world, farmers have often pulled large quantities of stone out of their fields to make farming easier and have stacked those stones to make walls that either mark the field boundary, or the property boundary, or both.

[[Retaining wall]]s resist movement of earth, stone, or water. They may be part of a building or external. The ground surface or water on one side of a retaining wall is typically higher than on the other side. A [[dike (construction)|dike]] is a retaining wall, as is a [[levee]], a load-bearing [[Foundation (engineering)|foundation]] wall, and a [[sea wall]].

==Shared wall==
Special laws often govern walls that neighbouring properties share. Typically, one neighbour cannot alter the common wall if it is likely to affect the building or property on the other side. A wall may also separate apartment or hotel rooms from each other. Each wall has two sides and breaking a wall on one side will break the wall on the other side.

==Portable wall==
Portable walls, such as [[room dividers]] or [[portable partitions]] divide a larger open space into smaller rooms. Portable walls can be static, such as cubicle walls, or can be wall panels mounted on casters to provide an easy way to reconfigure assembly space. They are often found inside schools, churches, convention centers, hotels, and corporate facilities.

==Temporary wall==
A temporary wall is constructed for easy removal or demolition. A typical temporary wall can be constructed with {{cvt|1/2|in|mm}} to {{cvt|5/8|in|mm}} sheet rock (plasterboard), metal {{nowrap|2 × 3 s}} ({{cvt|1+1/2|x|2+1/2|in|mm|disp=comma}}) or {{nowrap|2 × 4 s}} ({{cvt|1+1/2|x|3+1/2|in|mm|disp=comma}}), or taped, plastered and compounded. Most installation companies use lattice (strips of wood) to cover the joints of the temporary wall with the ceiling. These are sometimes known as [[pressurized wall]]s or temporary pressurized walls.

==Walls in popular culture==
Walls are often seen in popular culture, oftentimes representing barriers preventing progress or entry. For example:

;Fictional and symbolic walls

The progressive/psychedelic rock band [[Pink Floyd]] used a metaphorical wall to represent the isolation felt by the protagonist of their 1979 concept album ''[[The Wall]]''.

The [[United States|American]] [[poet laureate]] [[Robert Frost]] describes a pointless rock wall as a metaphor for the myopia of the culture-bound in his poem "[[Mending Wall]]", published in 1914.

Walls are a recurring symbol in [[Ursula K. Le Guin]]'s 1974 novel ''[[The Dispossessed]]''.

In some cases, a wall may refer to an individual's debilitating mental or physical condition, seen as an impassable barrier.{{citation needed|date=April 2019}}

In [[George R. R. Martin]]'s ''[[A Song of Ice and Fire]]'' series and its television adaptation, ''[[Game of Thrones]]'', The Wall plays multiple important roles: as a colossal fortification, made of ice and fortified with magic spells; as a cultural barrier; and as a codification of assumptions. Breaches of the wall, who is allowed to cross it and who is not, and its destruction have important symbolic, logistical, and socio-political implications in the storyline. Reportedly over {{convert|700|ft}} high and {{convert|100|league|mi km}} wide, it divides the northern border of the Seven Kingdoms realm from the domain of the wildlings and several categories of undead who live beyond it.<ref>{{cite news|work=Vulture|title=Game of Thrones: Everything to Know About the Wall |url=https://www.vulture.com/2017/08/game-of-thrones-the-wall-explained.html|date=August 27, 2017}}</ref><ref>{{cite news|date=April 15, 2019|url=https://www.telegraph.co.uk/tv/0/game-thrones-wall-built-destruction-means/ |archive-url=https://ghostarchive.org/archive/20220112/https://www.telegraph.co.uk/tv/0/game-thrones-wall-built-destruction-means/ |archive-date=2022-01-12 |url-access=subscription |url-status=live|work=Telegraph|title=Game of Thrones Wall: How the Wall was built, and what its destruction means}}{{cbignore}}</ref><ref>{{cite news|title='Game of Thrones' Season 8: How Was The Wall Built? |work= Newsweek|date=April 7, 2019|url=https://www.newsweek.com/game-thrones-wall-1380670}}</ref>

;Historical walls
In a real-life example, the [[Berlin Wall]], constructed by the [[Soviet Union]] to divide [[Berlin]] into [[NATO]] and [[Warsaw Pact]] zones of occupation, became a worldwide symbol of oppression and isolation.<ref>{{cite news |last=Preuss |first=Evelyn |date=2005 |title=The Wall You Will Never Know |pages=19–31 |work=Perspecta 036: The Yale Architectural Journal |publisher=MIT Press |location=Cambridge, MA |url=https://www.academia.edu/17812963}}</ref>

;Social media walls
Another common usage is as a communal surface to write upon. For instance the social networking site [[Facebook]] previously used an electronic "wall" to log the scrawls of friends until it was replaced by the "timeline" feature.

==See also==
{{div col|colwidth=15em}}
* [[Ashlar]]
* [[Chemise (wall)]]
* [[Clay panel]]
* [[Climbing wall]]
* [[Crinkle crankle wall]]
* [[Fabric structure]]
* [[Great Green Wall (Africa)]]
* [[Great Green Wall (China)]]
* [[Green wall]]
* [[List of walls]]
* [[Sleeper wall]]
* [[Stone wall]]
* [[Tensile structure]]
* [[Terraced wall]]
* [[Thin-shell structure]]
* [[Wallpaper]]
{{div col end}}

==References==
{{Reflist}}

==External links==
{{EB1911 poster|Wall}}
* {{Wikiquote-inline}}
* {{Wiktionary-inline|wall}}
*{{Commons category-inline}}

{{Room|state=collapsed}}
{{Authority control}}

[[Category:Walls| ]]
[[Category:Archaeological features]]
[[Category:Home]]
[[Category:Property law]]
[[Category:Structural system]]