Clerestory
Inarchitecture,aclerestory(/ˈklɪərstɔːri/KLEER-stor-ee;lit. 'clear storey',alsoclearstory,clearstorey,oroverstorey;fromOld Frenchcler estor) is a high section of wall that containswindowsabove eye-level. Its purpose is to admit light, fresh air, or both.
Historically, aclerestoryformed an upper level of a Romanbasilicaor of thenaveof aRomanesqueorGothicchurch,the walls of which rise above the rooflines of the loweraislesand which are pierced with windows.
Clerestoryhave been used in transportation vehicles to provide additional lighting, ventilation, or headroom.
History[edit]
Ancient world[edit]
The technology of the clerestory appears to originate in thetemplesofancient 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 theAmarnaperiod.[1]
In theMinoanpalaces ofCretesuch asKnossos,by contrast,lightwellswere employed in addition to clerestories.[2]
According to Biblical accounts, the Hebrewtemplebuilt byKing Solomonfeatured clerestory windows made possible by the use of a tall, angled roof and a centralridgepole.[3]
The clerestory was used in theHellenistic architectureof the later periods ofancient Greekcivilization. The Romans applied clerestories tobasilicasof justice and to the basilica-like bath-houses and palaces.
Early Christian and Byzantine basilicas[edit]
Early Christianchurches and some Byzantine churches, particularly in Italy, are based closely on the Roman basilica, and maintained the form of a centralnaveflanked 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[edit]
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 havebarrel-vaultedceilings with no clerestory. The development of thegroin vaultandribbed vaultmade possible the insertion of clerestory windows.
Initially the nave of a large aisled and clerestoried church was of two levels:arcadeand 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 inAugsburg CathedralinBavaria,Germany.
Gothic period[edit]
In smaller churches, clerestory windows may betrefoilsorquatrefoils.In some Italian churches they areocular.In most large churches, they are an important feature, both for beauty and for utility. Theribbed vaultingandflying buttressesof Gothic architecture concentrated the weight and thrust of the roof, freeing wall-space for larger clerestoryfenestration.Generally, in Gothic masterpieces, the clerestory is divided intobaysby 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 ofAmiens CathedralorWestminster Abbey,where their clerestories account for nearly a third of the height of the interior.[4]
Modern clerestory windows for energy-efficient buildings[edit]
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, besidesdaylightingandventilation:they can be part ofpassive solarstrategies, in very energy-efficient buildings (passive housesandzero-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 storesolar heat gainsduring 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[edit]
Clerestory roofs were incorporated into the designs of manyrailway passenger carsandtrams(CE) / streetcars (AE&CE) 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 firstPullman coachesin 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 theMidland Railway,a predecessor of theLondon 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 theLondon Undergroundwere the'Q' stock,which were withdrawn from operation in 1971.[11]
Clerestories were also used in early Britishdouble-decker buses,giving betterventilationand headroom in the centre corridor, as well as betterillumination.[12]
TheVolkswagen Type 2Kombi, 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 inRomanycaravans, such asvardos,and other caravans.
See also[edit]
- Architecture of cathedrals and great churches
- Gothic architecture
- Passive daylighting
- Romanesque architecture
- Roof window
- Säteritak,a Swedish roof style with a strip of clerestory-type of windows halfway up a hip roof
References[edit]
- ^Gwendolyn Leick and Francis J. Kirk,A Dictionary of Ancient Near Eastern Architecture,1988, Routledge, 261 pagesISBN0-415-00240-0
- ^C. Michael Hogan,Knossos fieldnotes,Modern Antiquarian (2007)
- ^Palmer, Allison Lee (11 September 2008).Historical Dictionary of Architecture.Scarecrow Press. p. 267.ISBN978-0-8108-6283-8.Retrieved15 June2014.
- ^Simpson, Frederick Moore (1922).History of Architectural Development.Longmans, Green, and Company. p. 273.
- ^"Siting with the Sun: Passive Heating and Daylighting"Archived11 July 2018 at theWayback Machine.GreenBuildingAdvisor
- ^"Clerestory Windows: Advantages and Downsides".House-energy.
- ^Cotey, Angela (21 January 2011)."Civil War rails".Trains.Kalmbach Media.Retrieved18 February2024.
registration:a free registration is required to access the source. - ^Harter, Jim (2005),World Railways of the Nineteenth Century: A Pictorial History in Victorian Engravings,Johns Hopkins University Press, p. 248,ISBN9780801880896
- ^Kichenside, G.M. (1964),Railway carriages, 1839-1939,Ian Allan, Clerestory Roofs, p.12
- ^Radford, J B (1984).The American Cars of the Midland Railway.London: Ian Allan. p. 15 etc.ISBN0-7110-1387-X.
- ^"RW Carroll Collection".Flickr.6 May 2012.Retrieved22 July2015.
- ^Klapper, Charles F. (1984) [1978],The Golden Age of Buses,Routledge, p. 16,ISBN9780710202321
External links[edit]
- Clerestory coach (railway) images– nineteenth-century examples from more than 20 countries
