A clerestory ( ; , also clearstory, clearstorey, or overstorey; from

Old French Old French (, , ; ) was the language spoken in most of the northern half of France approximately between the late 8th [2-4; we might wonder whether there's a point at which it's appropriate to talk of the beginnings of French, that is, when it wa ...

''cler estor'') is a high section of wall that contains windows above eye-level. Its purpose is to admit light, fresh air, or both. Historically, a ''clerestory'' formed an upper level of a Roman

basilica In Ancient Roman architecture, a basilica (Greek Basiliké) was a large public building with multiple functions that was typically built alongside the town's forum. The basilica was in the Latin West equivalent to a stoa in the Greek Eas ...

or of the

nave The nave () is the central part of a church, stretching from the (normally western) main entrance or rear wall, to the transepts, or in a church without transepts, to the chancel. When a church contains side aisles, as in a basilica-type ...

of a Romanesque or Gothic architecture, Gothic

church Church may refer to: Religion * Church (building), a place/building for Christian religious activities and praying * Church (congregation), a local congregation of a Christian denomination * Church service, a formalized period of Christian comm ...

, the walls of which rise above the rooflines of the lower

aisle An aisle is a linear space for walking with rows of non-walking spaces on both sides. Aisles with seating on both sides can be seen in airplanes, in buildings such as churches, cathedrals, synagogues, meeting halls, parliaments, courtrooms, ...

s and which are pierced with windows. In addition to

architecture Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and construction, constructi ...

, clerestories have been used in transportation vehicles such as buses and trains to provide additional lighting, ventilation, or headroom.

History

Ancient world

Clerestories appear to originate in

Egyptian temple Egyptian temples were built for the official worship of the gods and in commemoration of the pharaohs in ancient Egypt and regions under Egyptian control. Temples were seen as houses for the gods or kings to whom they were dedicated. Within them ...

s, where the lighting of the hall of columns was obtained over the stone roofs of the adjoining aisles, through gaps left in the vertical slabs of stone. They appeared in Egypt at least as early as the Amarna Period.

Minoan palaces Minoan palaces were massive building complexes built on Crete during the Bronze Age. They are often considered emblematic of the Minoan civilization and are modern tourist destinations. Archaeologists generally recognize five structures as palac ...

Crete Crete ( ; , Modern Greek, Modern: , Ancient Greek, Ancient: ) is the largest and most populous of the Greek islands, the List of islands by area, 88th largest island in the world and the List of islands in the Mediterranean#By area, fifth la ...

such as

Knossos Knossos (; , ; Linear B: ''Ko-no-so'') is a Bronze Age archaeological site in Crete. The site was a major centre of the Minoan civilization and is known for its association with the Greek myth of Theseus and the minotaur. It is located on th ...

employed

lightwell In architecture, a lightwell,light well, light-well sky-well,skywell, sky well or air shaft is an unroofed or roofed external space provided within the volume of a large building to allow light and air to reach what would otherwise be a dark or u ...

s in addition to clerestories. According to the

Hebrew Bible The Hebrew Bible or Tanakh (;"Tanach"
. '' Solomon's Temple Solomon's Temple, also known as the First Temple (), was a biblical Temple in Jerusalem believed to have existed between the 10th and 6th centuries Common Era, BCE. Its description is largely based on narratives in the Hebrew Bible, in which it ...

featured clerestory windows made possible by the use of a tall, angled roof and a central . The clerestory was used in the

Hellenistic architecture Hellenistic art is the art of the Hellenistic period generally taken to begin with the death of Alexander the Great in 323 BC and end with the Roman Greece, conquest of the Greek world by the Romans, a process well underway by 146 BC, when the G ...

classical antiquity Classical antiquity, also known as the classical era, classical period, classical age, or simply antiquity, is the period of cultural History of Europe, European history between the 8th century BC and the 5th century AD comprising the inter ...

. The Romans applied clerestories to

s of justice and to the basilica-like

thermae In ancient Rome, (from Greek , "hot") and (from Greek ) were facilities for bathing. usually refers to the large Roman Empire, imperial public bath, bath complexes, while were smaller-scale facilities, public or private, that existed i ...

and palaces.

Early Christian and Byzantine basilicas

Early Christian Early Christianity, otherwise called the Early Church or Paleo-Christianity, describes the historical era of the Christian religion up to the First Council of Nicaea in 325. Christianity spread from the Levant, across the Roman Empire, and be ...

churches and some Byzantine churches, particularly in Italy, are based closely on the Roman basilica, and maintained the form of a central

flanked by lower aisles on each side. The nave and aisles are separated by columns or piers, above which rises a wall pierced by clerestory windows.

Romanesque period

During the Romanesque period, many churches of the basilica form were constructed all over Europe. Many of these churches have wooden roofs with clerestories below them. Some Romanesque churches have

barrel-vaulted A barrel vault, also known as a tunnel vault, wagon vault or wagonhead vault, is an architectural element formed by the extrusion of a single curve (or pair of curves, in the case of a pointed barrel vault) along a given distance. The curves are ...

ceilings with no clerestory. The development of the

groin vault A groin vault or groined vault (also sometimes known as a double barrel vault or cross vault) is produced by the intersection at right angles of two barrel vaults. Honour, H. and J. Fleming, (2009) ''A World History of Art''. 7th edn. London: La ...

and

ribbed vault A rib vault or ribbed vault is an architectural feature for covering a wide space, such as a nave, church nave, composed of a framework of crossed or diagonal arched ribs. Variations were used in Roman architecture, Byzantine architecture, Isla ...

made possible the insertion of clerestory windows. Initially the nave of a large aisled and clerestoried church was of two levels:

arcade Arcade most often refers to: * Arcade game, a coin-operated video, pinball, electro-mechanical, redemption, etc., game ** Arcade video game, a coin-operated video game ** Arcade cabinet, housing which holds an arcade video game's hardware ** Arcad ...

and clerestory. During the Romanesque period, a third level was inserted between them, a gallery called the "

triforium A triforium is an interior Gallery (theatre), gallery, opening onto the tall central space of a building at an upper level. In a church, it opens onto the nave from above the side aisles; it may occur at the level of the clerestory windows, o ...

". The triforium generally opens into space beneath the sloping roof of the aisle. This became a standard feature of later Romanesque and Gothic large abbey and cathedral churches. Sometimes another gallery set into the wall space above the triforium and below the clerestory. This feature is found in some late Romanesque and early Gothic buildings in France. The oldest glass clerestory windows still in place are from the late eleventh century, found in

Augsburg Cathedral The Cathedral of Augsburg (German: ''Dom Mariä Heimsuchung'') is a Catholic cathedral in Augsburg, Bavaria, Germany, founded in the 11th century in Romanesque style, but with 14th-century Gothic additions. Together with the Basilica of St. Ul ...

Bavaria Bavaria, officially the Free State of Bavaria, is a States of Germany, state in the southeast of Germany. With an area of , it is the list of German states by area, largest German state by land area, comprising approximately 1/5 of the total l ...

, Germany.

Gothic period

In smaller churches, clerestory windows may be

trefoil A trefoil () is a graphic form composed of the outline of three overlapping rings, used in architecture, Pagan and Christian symbolism, among other areas. The term is also applied to other symbols with a threefold shape. A similar shape with f ...

s or

quatrefoil A quatrefoil (anciently caterfoil) is a decorative element consisting of a symmetrical shape which forms the overall outline of four partially overlapping circles of the same diameter. It is found in art, architecture, heraldry and traditional ...

s. In some Italian churches they are

ocular An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the eye ...

. In most large churches, they are an important feature, both for beauty and for utility. The

ing and

flying buttress The flying buttress (''arc-boutant'', arch buttress) is a specific form of buttress composed of a ramping arch that extends from the upper portion of a wall to a pier of great mass, to convey to the ground the lateral forces that push a wall ou ...

es of Gothic architecture concentrated the weight and thrust of the roof, freeing wall-space for larger clerestory fenestration. Generally, in Gothic masterpieces, the clerestory is divided into

bays A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a ''gulf'', ''sea'', ''sound'', or ''bight''. A ''cove'' is a small, ci ...

by the vaulting shafts that continue the same tall columns that form the arcade separating the aisles from the nave. The tendency from the early Romanesque period to the late Gothic period was for the clerestory level to become progressively taller and the size of the windows to get proportionally larger in relation to wall surface, emerging in works such as the Gothic architecture of

Amiens Cathedral The Cathedral of Our Lady of Amiens (), or simply Amiens Cathedral, is a Catholic Church, Catholic cathedral. The cathedral is the seat of the Bishop of Amiens. It is situated on a slight ridge overlooking the River Somme in Amiens, the administra ...

Westminster Abbey Westminster Abbey, formally titled the Collegiate Church of Saint Peter at Westminster, is an Anglican church in the City of Westminster, London, England. Since 1066, it has been the location of the coronations of 40 English and British m ...

, where their clerestories account for nearly a third of the height of the interior.

Today

874Rizal Cainta Roads Buildings Landmarks 29

Modern clerestories often are defined as vertical windows, located on high walls, extending up from the roofline, designed to allow light and breezes into a space, without compromising privacy. Factory buildings often are built with clerestory windows; modern housing designs sometimes include them as well. Modern clerestory windows may have another especially important role, besides

daylighting Daylighting can refer to: * Daylighting (architecture), use of windows for indirect lighting * Daylighting (intersections), improving road visibility at intersections * Daylighting (streams), restoration of a previously buried watercourse * Dayl ...

and

ventilation Ventilation may refer to: * Ventilation (physiology), the movement of air between the environment and the lungs via inhalation and exhalation ** Mechanical ventilation, in medicine, using artificial methods to assist breathing *** Respirator, a ma ...

: they can be part of

passive solar In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy, in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unli ...

strategies, in very energy-efficient buildings (

passive house Passive house () is a voluntary standard for energy efficiency in a building that reduces the building's carbon footprint. Conforming to these standards results in ultra-low energy buildings that require less energy for space heating or co ...

s and

zero-energy building A Zero-Energy Building (ZEB), also known as a Net Zero-Energy (NZE) building, is a building with net zero energy consumption, meaning the total amount of energy used by the building on an annual basis is equal to the amount of renewable energy c ...

s). To that end, clerestories are used in conjunction with stone, brick, concrete, and other high-mass walls and floors, properly positioned to store

solar heat gain Solar gain (also known as solar heat gain or passive solar gain) is the increase in thermal energy of a space, object or structure as it absorbs incident solar radiation. The amount of solar gain a space experiences is a function of the total i ...

s during the hotter parts of the day – allowing the walls and the floor to act as a heat bank during the cooler parts of the day. Clerestories – in passive solar strategies – should be properly located (typically in the sunny side of the building) and protected from the summer's sun by rooflines, overhangs, recessed thick walls, or other architectural elements, in order to prevent overheating during the cooling season.

In transportation

Clerestory roofs were incorporated into the designs of many railway passenger cars and

tram A tram (also known as a streetcar or trolley in Canada and the United States) is an urban rail transit in which Rolling stock, vehicles, whether individual railcars or multiple-unit trains, run on tramway tracks on urban public streets; some ...

Commonwealth English The use of the English language in current and former Member states of the Commonwealth of Nations, countries of Commonwealth of Nations, the Commonwealth was largely inherited from British Empire, British colonisation, with some exceptions. Eng ...

) / streetcars (

American English American English, sometimes called United States English or U.S. English, is the set of variety (linguistics), varieties of the English language native to the United States. English is the Languages of the United States, most widely spoken lang ...

Canadian English Canadian English (CanE, CE, en-CA) encompasses the Variety (linguistics), varieties of English language, English used in Canada. According to the 2016 Canadian Census, 2016 census, English was the first language of 19.4 million Canadians or ...

) from about 1860 to the 1930s. They increased the daylight and ventilation available to passengers. In the US, the railroad clerestory roof was also known as the "lantern roof". The first Pullman coaches in the UK had clerestory roofs. They were imported from the US and assembled at Derby, where Pullman set up an assembly plant in conjunction with the

Midland Railway The Midland Railway (MR) was a railway company in the United Kingdom from 1844 in rail transport, 1844. The Midland was one of the largest railway companies in Britain in the early 20th century, and the largest employer in Derby, where it had ...

, a predecessor of the

London Midland and Scottish Railway The London, Midland and Scottish Railway (LMSIt has been argued that the initials LMSR should be used to be consistent with LNER, GWR and SR. The London, Midland and Scottish Railway's corporate image used LMS, and this is what is generally ...

(LMS). The first coach, a sleeping car named "Midland", was assembled and ready for trial-running in January 1874. The last clerestory-roofed trains on the

London Underground The London Underground (also known simply as the Underground or as the Tube) is a rapid transit system serving Greater London and some parts of the adjacent home counties of Buckinghamshire, Essex and Hertfordshire in England. The Undergro ...

were the 'Q' stock, which were withdrawn from operation in 1971. Clerestories were also used in early British

double-decker bus A double-decker bus is a bus that has two storeys or decks. Double-deckers are used primarily for commuter transport, but open-top models are used as sightseeing buses for tourists, and there are coaches too for long-distance travel. They app ...

es, giving better

and headroom in the centre corridor, as well as better illumination. The

Volkswagen Type 2 The Volkswagen Transporter, initially the Type 2, is a range of light commercial vehicles, built as vans, pickups, and cab-and-chassis variants, introduced in 1950 by the German automotive industry, automaker Volkswagen as their second mass ...

Kombi, or Transport, commonly called the Microbus, came in a deluxe version with clerestory windows. VW made the Samba from 1961 to 1967 in several versions, which had as many as 23 windows, and it is highly prized by collectors. In the UK, the style is also known as "mollycroft roof", especially in Romany caravans, such as vardos, and other caravans.

References

External links

Clerestory coach (railway) images
– nineteenth-century examples from more than 20 countries {{Roofs Church architecture Windows Architectural elements Energy-saving lighting Sustainable building