Clerestory

Source: Wikipedia, the free encyclopedia.

Gothic cathedral
, with clerestory highlighted
St Nicholas, Stralsund in Germany – the clerestory is the level between the two green roofs, reinforced here by flying buttresses
.

In architecture, a clerestory (/ˈklɪərstɔːri/ KLEER-stor-ee; lit.'clear storey', also clearstory, clearstorey, or overstorey; from Old French 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 or of the nave of a Romanesque or Gothic church, the walls of which rise above the rooflines of the lower aisles and which are pierced with windows.

Similar structures have been used in transportation vehicles to provide additional lighting, ventilation, or headroom.

History

The walls of the clerestory of the basilica-shaped Cathedral of Monreale, Italy are covered with mosaic

Ancient world

The technology of the clerestory appears to originate in the temples of ancient Egypt. The term "clerestory" is applicable to Egyptian temples, 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. Clerestory appeared in Egypt at least as early as the Amarna period.[1]

In the Minoan palaces of Crete such as Knossos, by contrast, lightwells were employed in addition to clerestories.[2]

According to Biblical accounts, the Hebrew temple built by King Solomon featured clerestory windows made possible by the use of a tall, angled roof and a central ridgepole.[3]

The clerestory was used in the

ancient Greek civilization. The Romans applied clerestories to basilicas
of justice and to the basilica-like bath-houses and palaces.

Early Christian and Byzantine basilicas

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

Malmesbury Abbey, Wiltshire, England. The nave wall is divided into three stages: the upper stage with windows is the clerestory, beneath it is the triforium, and the lowest stage is the arcade.

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

ribbed vault
made possible the insertion of clerestory windows.

Initially the nave of a large aisled and clerestoried church was of two levels: arcade and clerestory. During the Romanesque period, a third level was inserted between them, a gallery called the "triforium". 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 in Bavaria, Germany.

Gothic period

The clerestory of Amiens Cathedral in northern France

In smaller churches, clerestory windows may be

fenestration. Generally, in Gothic masterpieces, the clerestory is divided into bays
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 or Westminster Abbey, where their clerestories account for nearly a third of the height of the interior.[4]

Modern clerestory windows for energy-efficient buildings

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

passive solar strategies, in very energy-efficient buildings (passive houses and zero-energy buildings).[5]

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 gains 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.[6]

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.

Transportation

Barney and Smith Car Company clerestory-roofed cars at the Mid-Continent Railway Museum. As in these examples, most clerestory roofs of passenger cars ended in a bullnose.
Interior of the clerestory roof of a 1908-vintage tram at the Tramway Museum, St Kilda, South Australia

Clerestory roofs were incorporated into the designs of many

railway passenger cars and trams (CE) / streetcars (AE) from about 1860[7] to the 1930s.[8][9]
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

London Midland and Scottish Railway (LMS). The first coach, a sleeping car named "Midland", was assembled and ready for trial-running in January 1874.[10]

The last clerestory-roofed trains on the London Underground were the 'Q' stock, which were withdrawn from operation in 1971.[11]

Clerestories were also used in early British

illumination.[12]

The Volkswagen Type 2 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.

See also

References

  1. ^ C. Michael Hogan, Knossos fieldnotes, Modern Antiquarian (2007)
  2. . Retrieved 15 June 2014.
  3. ^ Simpson, Frederick Moore (1922). History of Architectural Development. Longmans, Green, and Company. p. 273.
  4. ^ "Siting with the Sun: Passive Heating and Daylighting" Archived 11 July 2018 at the Wayback Machine. GreenBuildingAdvisor.com
  5. ^ "Clerestory Windows: Advantages and Downsides". House-energy.com.
  6. ^ Cotey, Angela (21 January 2011). "Civil War rails". Trains. Kalmbach Media. Retrieved 18 February 2024.  Free registration required registration: a free registration is required to access the source.
  7. ^ Kichenside, G.M. (1964), Railway carriages, 1839-1939, Ian Allan, Clerestory Roofs, p.12
  8. .
  9. ^ "RW Carroll Collection". Flickr. 6 May 2012. Retrieved 22 July 2015.

External links