Magic, along with its subgenres of, sometimes referred to as illusion, stage magic or close up magic is a performing art in which audiences are entertained by staged tricks or illusions of impossible feats using natural means. It is to be distinguished from paranormal magic which are effects claimed to be created through supernatural means, it is one of the oldest performing arts in the world. Modern entertainment magic, as pioneered by 19th-century magician Jean Eugène Robert-Houdin, has become a popular theatrical art form. In the late 19th and early 20th centuries, magicians such as Maskelyne and Devant, Howard Thurston, Harry Kellar, Harry Houdini achieved widespread commercial success during what has become known as "The Golden Age of Magic". During this period, performance magic became a staple of Broadway theatre and music halls. Magic retained its popularity in the television age, with magicians such as David Copperfield, Doug Henning, Penn & Teller, David Blaine modernizing the art form.
The term "magic" etymologically derives from the Greek word mageia. In ancient times and Persians had been at war for centuries, the Persian priests, called magosh in Persian, came to be known as magoi in Greek. Ritual acts of Persian priests came to be known as mageia, magika—which came to mean any foreign, unorthodox, or illegitimate ritual practice. During the 17th century, many books were published; until the 18th century, magic shows were a common source of entertainment at fairs. A founding figure of modern entertainment magic was Jean Eugène Robert-Houdin, who had a magic theatre in Paris in 1845. John Henry Anderson was pioneering the same transition in London in the 1840s. Towards the end of the 19th century, large magic shows permanently staged at big theatre venues became the norm; as a form of entertainment, magic moved from theatrical venues to television magic specials. Performances that modern observers would recognize as conjuring have been practiced throughout history. For many recorded centuries, magicians were associated with the occult.
During the 19th and 20th centuries, many stage magicians capitalized on this notion in their advertisements. The same level of ingenuity, used to produce famous ancient deceptions such as the Trojan Horse would have been used for entertainment, or at least for cheating in money games, they were used by the practitioners of various religions and cults from ancient times onwards to frighten uneducated people into obedience or turn them into adherents. However, the profession of the illusionist gained strength only in the 18th century, has enjoyed several popular vogues since. Opinions vary among magicians on how to categorize a given effect, but a number of categories have been developed. Magicians may pull a rabbit from an empty hat, make something seem to disappear, or transform a red silk handkerchief into a green silk handkerchief. Magicians may destroy something, like cutting a head off, "restore" it, make something appear to move from one place to another, or they may escape from a restraining device.
Other illusions include making something appear to defy gravity, making a solid object appear to pass through another object, or appearing to predict the choice of a spectator. Many magic routines use combinations of effects. One of the earliest books on the subject is Gantziony's work of 1489, Natural and Unnatural Magic, which describes and explains old-time tricks. In 1584, Englishman Reginald Scot published The Discoverie of Witchcraft, part of, devoted to debunking the claims that magicians used supernatural methods, showing how their "magic tricks" were in reality accomplished. Among the tricks discussed were sleight-of-hand manipulations with rope and coins. At the time and belief in witchcraft was widespread and the book tried to demonstrate that these fears were misplaced. Popular belief held that all obtainable copies were burned on the accession of James I in 1603. During the 17th century, many similar books were published that described in detail the methods of a number of magic tricks, including The Art of Conjuring and The Anatomy of Legerdemain: The Art of Juggling.
Until the 18th century, magic shows were a common source of entertainment at fairs, where itinerant performers would entertain the public with magic tricks, as well as the more traditional spectacles of sword swallowing and fire breathing. In the early 18th century, as belief in witchcraft was waning, the art became respectable and shows would be put on for rich private patrons. A notable figure in this transition was the English showman, Isaac Fawkes, who began to promote his act in advertisements from the 1720s – he claimed to have performed for King George II. One of Fawkes' advertisements described his routine in some detail: He takes an empty bag, lays it on the Table and turns it several times inside out commands 100 Eggs out of it and several showers of real Gold and silver the Bag beginning to swell several sorts of wild fowl run out of it upon the Table, he throws up a Pack of Cards, causes them to be living birds flying about the room. He causes living Beasts and other Creatures to appear upon the Table.
He blows the spots of the Cards off and on, changes them to any pictures. From 1756 to 1781, Jacob Philadelphia performed feats of magic, sometimes under the guise of scientific exhibitions, throughout Europe and in Russia. A founding figure of modern entertainment magic was Jean Eugène Robert-Houdin a clockmaker, who opened a magic theatre in Paris in 1845, he transformed his art from one performed at fairs to a performance that the public paid to see at the theatre. His
Thierry Geoffroy known as Colonel, is a Danish-French artist, living in Copenhagen, Denmark. He is a Conceptual artist using a wide variety of media including video and installations collaborative with other artists. Geoffroy refers to his work as "format art". In 1989 he wrote a manifest on five types of moving exhibitions. Since he has worked on several other formats, his most famous being Emergency Room, which has toured internationally and has been shown at P. S. 1 Contemporary Art Center in New York City. The formats involve many participants and are designed to investigate social psychology, his method is inspired by the TV program format: art institutions wanting to use an art format must purchase a license and agree to use the original title, architectural concept, methods. As in TV, vast documentation is always created with photo material as central elements. Geoffroy devised the'Emergency Room' concept to allow artists to respond to current events quickly; the exhibits are changed every day.'Emergency Room' events have been held in Copenhagen, New York, Hanoi, Johannesburg and Paris.
Biennalist is another Art Format by Thierry Geoffroy / Colonel, concurrently commenting on active biennals and managed cultural events through artworks. Biennalist takes the thematics of the biennales and similar events like documenta and conferences questioning the established structures of the staged art events in order to contribute to the debate, which they wish to generate; the pertinence of the themes of the biennales is tested on location. Biennalist has been activated at the Istanbul Biennial 2007, Venice Biennale 1999, 2001, 2003, 2005, 2007, 2009, 2011, 2013 and 2015, Athens Biennale 2007 and 2011, Biennale of Sydney 2010, Sarema Biennale 1997, Rotterdam Biennale 1990, U-Turn Quadriennale 2008, Manifesta 2010 and Liverpool Biennial 2010; the "Penetration" format is an artist's act of placing an artwork within another artist's exhibition. The Penetration is a solution to avoid the lateness of bureaucratic art institutions, by circulating space between the actors – artist to artist.
A penetration is not only meant as a shortcut, but a beneficial collaboration. The format has been seen at the Athens Biennial Emergency Room, at the Istanbul Biennial, at the Venice Biennial in 2007, at the Venice Biennial in 2009; the "Penetration" format was activated at Manifesta 8 in Murcia. Here the format took place in a ` Penetration Room'; the 2010 Biennale took the theme of "North Africa" and Geoffroy invited North African artists to intervene the exhibition space. Geoffroy's "Extracteur" format involves sending a person to create a photographic collection of personal experience, it is designed to "retake the right to reread and reorganise the representation of the world" as a reaction to social media's collection of private information. He first used the format during the 2011 Venice Biennale; the "Awareness Muscle" format's goal is to train the collective "muscle of awareness". It uses the act of physical training as a metaphor for consciousness and critical thinking training. Geoffroy has made several productions for Danish national television DR2.
Among these the programs "Capitain", "Immigranten", "Photographe" and "Protest Underwear". The choice of media is changing and is concerned with the contemporary. Newspapers, fashion industry, internet domains, music festivals, performance and facebook are among the elements of the artists crossmedia praxis. Central to the philosophy of Thierry Geoffroy seems to be the concern that contemporary artists have an obligation to confront current themes; this is evident in his Emergency Room and Awareness Muscle formats. Parallel to the artists conceptual format art work, he has worked with topics such as immigration, colonialism, tourism and the role of the artist. Manifeste Moving Exhibition, Brandts Klædefabrik, Denmark, 1989 Sport Art Manifeste, Brandts Klædefabrik, Denmark, 1991 Sport Art Manifeste, Bildtidningen, 1991 Colour Manifeste, Zoom, März 1991 Le conclusionisme, L'Alliance In dialogue with Northern Africa, Manifesta 8, Murcia 2010 2010, "Emergency Room Dictionary", Revolver, ISBN 978-3-86895-093-9, The Royal Danish Academy of Fine Arts 2005, "Self-measurements of Scottishness", text by Claudia Zeiske and Kevin Henderson 2002, "Avoir l' air", Forlaget Nifca, text by Rune Gade and Line Rosenvinge, Helsinki The Nordic Institute for Contemporary Art 2002 1997, "Tourists in Thailand", Rhodos Forlag 1996, "Strategies d´existence", ISBN 978-87-7245-694-2, Rhodos Publishing 1995, Kulturministeriets Fotografiske Bogpris 2003, "Chevalier des Arts et des Lettres" 2002, 3 years working grant from The National Arts Council 1995, Kulturministeriets Fotografiske Bogpris 2013-2014, "In advance of the broken arm?"
Gallery Marianne Fries, Copenhagen 2011, Art Format: Emergency Room Poland, guest: Emergency Artists 2011, Art Format: Emergency Room Vietnam, University of fine arts, guest: Emergency Artists 2009, "Artistes de Garde" at gallery Poulsen, guest: the Yes Men and Emergency Artists 2009, Art Format: Emergency Room Hanoi, University of fine arts with Emergency Artists 2009, PAN / NAPOLI format "Emergency Room
In the fields of physical security and information security, access control is the selective restriction of access to a place or other resource. The act of accessing may mean entering, or using. Permission to access a resource is called authorization. Locks and login credentials are two analogous mechanisms of access control. Geographical access control may be enforced with a device such as a turnstile. There may be fences to avoid circumventing this access control. An alternative of access control in the strict sense is a system of checking authorized presence, see e.g. Ticket controller. A variant is e.g. of a shop or a country. The term access control refers to the practice of restricting entrance to a property, a building, or a room to authorized persons. Physical access control can be achieved by a human, through mechanical means such as locks and keys, or through technological means such as access control systems like the mantrap. Within these environments, physical key management may be employed as a means of further managing and monitoring access to mechanically keyed areas or access to certain small assets.
Physical access control is a matter of who and when. An access control system determines, allowed to enter or exit, where they are allowed to exit or enter, when they are allowed to enter or exit; this was accomplished through keys and locks. When a door is locked, only someone with a key can enter through the door, depending on how the lock is configured. Mechanical locks and keys do not allow restriction of the key holder to specific dates. Mechanical locks and keys do not provide records of the key used on any specific door, the keys can be copied or transferred to an unauthorized person; when a mechanical key is lost or the key holder is no longer authorized to use the protected area, the locks must be re-keyed. Electronic access control uses computers to solve the limitations of mechanical keys. A wide range of credentials can be used to replace mechanical keys; the electronic access control system grants access based on the credential presented. When access is granted, the door is unlocked for a predetermined time and the transaction is recorded.
When access is refused, the door remains locked and the attempted access is recorded. The system will monitor the door and alarm if the door is forced open or held open too long after being unlocked; when a credential is presented to a reader, the reader sends the credential's information a number, to a control panel, a reliable processor. The control panel compares the credential's number to an access control list, grants or denies the presented request, sends a transaction log to a database; when access is denied based on the access control list, the door remains locked. If there is a match between the credential and the access control list, the control panel operates a relay that in turn unlocks the door; the control panel ignores a door open signal to prevent an alarm. The reader provides feedback, such as a flashing red LED for an access denied and a flashing green LED for an access granted; the above description illustrates a single factor transaction. Credentials can be passed around. For example, Alice has access rights to the server room.
Alice either gives Bob her credential. To prevent this, two-factor authentication can be used. In a two factor transaction, the presented credential and a second factor are needed for access to be granted. There are three types of authenticating information: something the user knows, e.g. a password, pass-phrase or PIN something the user has, such as smart card or a key fob something the user is, such as fingerprint, verified by biometric measurementPasswords are a common means of verifying a user's identity before access is given to information systems. In addition, a fourth factor of authentication is now recognized: someone you know, whereby another person who knows you can provide a human element of authentication in situations where systems have been set up to allow for such scenarios. For example, a user have forgotten their smart card. In such a scenario, if the user is known to designated cohorts, the cohorts may provide their smart card and password, in combination with the extant factor of the user in question, thus provide two factors for the user with the missing credential, giving three factors overall to allow access.
A credential is a physical/tangible object, a piece of knowledge, or a facet of a person's physical being that enables an individual access to a given physical facility or computer-based information system. Credentials can be something a person knows, something they have, something they are, or some combination of these items; this is known as multi-factor authentication. The typical credential is an access card or key-fob, newer software can turn users' smartphones into access devices. There are many card technologies including magnetic stripe, bar code, Wiegand, 125 kHz proximity, 26-bit card-swipe, contact smart cards, contactless smart cards. Available are key-fobs, which are more compact than ID cards, attach to a key ring. Biometric technologies include fingerprint, facial recognition, iris recognition, retinal scan and hand geometry; the built-in biometric technologies found o
Penetration is a punk rock band from County Durham, England formed in 1976. They re-formed in 2001 with several new members, their debut single, "Don't Dictate", is now acknowledged as a classic punk rock single and their debut album, Moving Targets, is still admired. The band's lineup was Robert Blamire, Gary Smallman and Gary Chaplin. Chaplin left in March 1978 being replaced with Neale Floyd, with second guitarist Fred Purser joining in July; the band dissolved in late 1979. They reformed in 2001 with original members Murray and Smallman, Steve Wallace and Paul Harvey drafted in as new guitarists. Formed in Ferryhill as The Points under which name they played their first gig at the Rock Garden pub in Middlesbrough in October 1976, they changed the band's name after a 1973 song by Iggy & The Stooges, their second gig was supporting The Stranglers at Newcastle City Hall. The band played at the now-legendary punk club The Roxy during its first 100 days. On 9 April 1977, the band appeared on the same bill as Generation X.
Early in their career, the band supported The Vibrators and toured with the Buzzcocks. After the release of their second single, Penetration recorded the first of two sessions for John Peel at BBC Radio 1 in July 1978; that year, the band released their debut album. Moving Targets was number 6 in the Sounds Critics' albums of the year. In 1979, they toured Europe, the US and Britain but the grueling schedule began to take its toll. A disappointing reaction to Coming Up For Air, the second album, was the final nail in the coffin of the original band. After the band split in October an official bootleg album called Race Against Time was released, a collection of early demos and live tracks. In 1980 Pauline Murray collaborated with The Invisible Girls, which included Robert Blamire as well as other Manchester musicians such as Vini Reilly, guitarist in The Durutti Column, Steve Hopkins. John Maher from Buzzcocks drummed for the band. Produced by Martin Hannett, the resulting album spawned the singles "Dream Sequence" and "Mr.
X", with a further non-album single "Searching for Heaven" released in 1981. Murray provided guest vocals for The Only Ones' 1980 track, "Fools". Former guitarist Gary Chaplin formed the short-lived new wave bands The Rhythm Clicks, which released the single "Short Time" in 1980, Soul On Ice which released the singles "Underwater" and "Widescreen" in 1982 and 1983 respectively. Pauline Murray worked sporadically as a solo artist under the name'Pauline Murray and The Storm' with Robert Blamire, Tim Johnston and Paul Harvey. Paul Harvey is a Stuckist artist. Blamire worked as a producer for various groups, including Scars, whose sole LP he produced. In 2015 Penetration announced the release of a new album called Resolution in October; the current line-up of the band is Pauline Murray, Robert Blamire, John Maher Paul Harvey and Steve Wallace. Moving Targets First 15,000 copies on luminous vinyl # 22 UK Albums Chart Coming Up For Air # 36 UK Race Against Time Resolution Don't Dictate: The Best of Penetration "Don’t Dictate" / "Money Talks" Re-released in 1983.
"Firing Squad" / "Never" "Life’s A Gamble" / "V. I. P." "Danger Signs" / "Stone Heroes" Also released, with an additional track "Vision", as a 12 inch single. "Come Into the Open" / "Lifeline" List of British punk bands List of musicians in the first wave of punk music List of Peel sessions Music of the United Kingdom Official website Penetration at AllMusic Penetration on www.punk77.co.uk
The Stooges known as Iggy and the Stooges, were an American rock band formed in Ann Arbor, Michigan in 1967 by singer Iggy Pop, guitarist Ron Asheton, drummer Scott Asheton, bassist Dave Alexander. Playing a raw, primitive style of rock and roll, the band sold few records in their original incarnation and gained a reputation for their confrontational performances, which involved acts of self-mutilation by Iggy Pop. After releasing two albums—The Stooges and Fun House —the group disbanded and reformed with a different lineup to release Raw Power before breaking up again in 1974; the band reunited in 2003 until dissolving in 2016 following the deaths of Scott Asheton and saxophonist Steve Mackay. Ron Asheton participated in the reunion until his death in 2009; the Stooges are regarded as a seminal proto-punk act. The band was inducted into the Rock and Roll Hall of Fame in 2010. In 2004, Rolling Stone ranked them 78th on their list of the 100 greatest artists of all time. Iggy Pop played drums in several Ann Arbor-area bands as a teenager, including the Iguanas and the Prime Movers.
The Prime Movers nicknamed Osterberg "Iggy" in reference to his earlier band. Osterberg was first inspired to form the Stooges after meeting blues drummer Sam Lay during a visit to Chicago. Upon returning to Detroit, Osterberg sought to create a new form of blues music, not derivative of historical precedents. Ron Asheton and Scott Asheton and Dave Alexander composed the rest of the band, with Osterberg as main singer. Osterberg became interested in Ron Asheton after seeing him perform in the Chosen Few, believing "I’ve never met a convincing musician that didn’t look kind of ill and kind of dirty, Ron had those two things covered!" The three nicknamed Osterberg "Pop" after a local character. Shortly after witnessing an MC5 concert in Ann Arbor, Osterberg began using the stage name Iggy Pop, a name that he has used since. Though the Stooges had formed, Iggy Pop attributes two key motivating influences to move the band forward; the first was seeing the Doors perform at a homecoming dance for the University of Michigan.
The second was seeing an all-girls rock band from Princeton, New Jersey called the Untouchable perform. In a 1995 interview with Bust Magazine, he relates: I had the Stooges, and we did not have the balls to do it. There were two things, and the other thing was. We had gone to New York a couple of months before that just to check out the scene, we had never been to a place like New York… we went down around Eighth Street there where all the young tourists hang out, we met these girls from New Jersey, from Princeton, they had a band called the Untouchable, we’re like, "Oh, you’ve got a band, sure, ha ha ha," and they said "Well, come to our house and see us play." And we didn’t have anywhere to crash, they played for us, they rocked, we were ashamed. The band's 1967 debut was at their communal State Street house on Halloween night, followed by their next live gig, January 1968. During this early period, the Stooges were billed as the "Psychedelic Stooges" at the Grande Ballroom in Detroit and other venues, where they played with the band MC5 and others.
At one of their early Grande Ballroom performances, Asheton's guitar neck separated from the body forcing the band to stop playing during the opening song, "I Wanna Be Your Dog". The group's early sound differed from their music. Homemade instruments were incorporated to flesh out the overall sound. The'Jim-a-phone' involved pushing feedback through a funnel device, raised and lowered to achieve the best effect. There was a cheap Hawaiian guitar which Pop and guitarist Ron Asheton would take turns in plucking to produce a simulated sitar drone, while drummer Scott Asheton pounded away at a set of oil drums with a ball hammer; the Stooges soon gained a reputation for their primitive live performances. Pop became known for his outrageous onstage behavior—smearing his bare chest with hamburger meat and peanut butter, cutting himself with shards of glass, flashing his genitalia to the audience. Pop is sometimes credited with the popularization of stage diving. In 1968 Elektra Records sent DJ/publicist Danny Fields to scout the MC5, resulting in contracts for both that band and the Stooges.
The contracts were at different pay rates: MC5 $20,000, the Stooges $5,000, as revealed in the 2016 Jim Jarmusch film, Gimme Danger. In 1969, the band released their self-titled debut album. In 1970, their second album, Fun House, was released, featuring the addition of saxophonist Steve Mackay. On June 13 of that year, television recorded the band at the Cincinnati Pop Festival. While performing the songs "T. V. Eye" and "1970", Pop leapt into the crowd, where he was hoisted up on people's hands, proceeded to smear peanut butter all over his chest. In a broadcast interview at WNUR Northwestern University radio station in Evanston, Illinois in 1984, Stiv Bators of the Lords of the New Church and the Dead Boys confirmed the long-standing rumor that it was he who had provided the peanut butter, having carrie
Basketball is a team sport in which two teams, most of five players each, opposing one another on a rectangular court, compete with the primary objective of shooting a basketball through the defender's hoop while preventing the opposing team from shooting through their own hoop. A field goal is worth two points, unless made from behind the three-point line, when it is worth three. After a foul, timed play stops and the player fouled or designated to shoot a technical foul is given one or more one-point free throws; the team with the most points at the end of the game wins, but if regulation play expires with the score tied, an additional period of play is mandated. Players advance the ball by bouncing it while walking or running or by passing it to a teammate, both of which require considerable skill. On offense, players may use a variety of shots -- a dunk, it is a violation to lift or drag one's pivot foot without dribbling the ball, to carry it, or to hold the ball with both hands resume dribbling.
The five players on each side at a time fall into five playing positions: the tallest player is the center, the tallest and strongest is the power forward, a shorter but more agile big man is the small forward, the shortest players or the best ball handlers are the shooting guard and the point guard, who implements the coach's game plan by managing the execution of offensive and defensive plays. Informally, players may play three-on-three, two-on-two, one-on-one. Invented in 1891 by Canadian-American gym teacher James Naismith in Springfield, United States, basketball has evolved to become one of the world's most popular and viewed sports; the National Basketball Association is the most significant professional basketball league in the world in terms of popularity, salaries and level of competition. Outside North America, the top clubs from national leagues qualify to continental championships such as the Euroleague and FIBA Americas League; the FIBA Basketball World Cup and Men's Olympic Basketball Tournament are the major international events of the sport and attract top national teams from around the world.
Each continent hosts regional competitions for national teams, like FIBA AmeriCup. The FIBA Women's Basketball World Cup and Women's Olympic Basketball Tournament feature top national teams from continental championships; the main North American league is the WNBA, whereas strongest European clubs participate in the EuroLeague Women. In early December 1891, Canadian James Naismith, a physical education professor and instructor at the International Young Men's Christian Association Training School in Springfield, was trying to keep his gym class active on a rainy day, he sought a vigorous indoor game to keep his students occupied and at proper levels of fitness during the long New England winters. After rejecting other ideas as either too rough or poorly suited to walled-in gymnasiums, he wrote the basic rules and nailed a peach basket onto a 10-foot elevated track. In contrast with modern basketball nets, this peach basket retained its bottom, balls had to be retrieved manually after each "basket" or point scored.
Basketball was played with a soccer ball. These round balls from "association football" were made, at the time, with a set of laces to close off the hole needed for inserting the inflatable bladder after the other sewn-together segments of the ball's cover had been flipped outside-in; these laces could dribbling to be unpredictable. A lace-free ball construction method was invented, this change to the game was endorsed by Naismith; the first balls made for basketball were brown, it was only in the late 1950s that Tony Hinkle, searching for a ball that would be more visible to players and spectators alike, introduced the orange ball, now in common use. Dribbling was not part of the original game except for the "bounce pass" to teammates. Passing the ball was the primary means of ball movement. Dribbling was introduced but limited by the asymmetric shape of early balls. Dribbling was common by 1896, with a rule against the double dribble by 1898; the peach baskets were used until 1906 when they were replaced by metal hoops with backboards.
A further change was soon made, so the ball passed through. Whenever a person got the ball in the basket, his team would gain a point. Whichever team got; the baskets were nailed to the mezzanine balcony of the playing court, but this proved impractical when spectators in the balcony began to interfere with shots. The backboard was introduced to prevent this interference. Naismith's handwritten diaries, discovered by his granddaughter in early 2006, indicate that he was nervous about the new game he had invented, which incorporated rules from a children's game called duck on a rock, as many had failed before it. Frank Mahan, one of the players from the original
Domestic roof construction
Domestic roof construction is the framing and roof covering, found on most detached houses in cold and temperate climates. Such roofs are built with timber, take a number of different shapes, are covered with a variety of materials. Modern timber roofs are framed with pairs of common rafters or prefabricated wooden trusses fastened together with truss connector plates. Timber framed and historic buildings may be framed with principal rafters or timber roof trusses. Roofs are designated as warm or cold roof depending on how they are designed and built with regard to thermal building insulation and ventilation; the steepness or roof pitch of a sloped roof is determined by the roof covering material and aesthetic design. Flat roofs slope up to ten degrees to shed water. Flat roofs on houses are found in arid regions. In high wind areas, such as where a cyclone or hurricane may make landfall, the main engineering consideration is to hold the roof down during severe storms; every component of the roof, as of course the rest of the structure, has to withstand the uplift forces of high wind speeds.
This is accomplished by using metal ties fastened to truss. This is not a problem in areas not prone to high wind or extreme weather conditions. In the UK, a concrete tiled roof would have rafters at 600mm centers, roof battens at 300mm centers and ceiling joists at 400mm centers; the United States still uses imperial units of measurement and framing members are spaced sixteen or twenty-four inches apart. The roof framing may be interrupted for openings such as skylight. Chimneys are built with a water diverter known as a cricket or saddle above the chimney. Flashing is used to seal the gap between the roofing material. A simple rafter roof consists of rafters that the rafter foot rest on horizontal wall plates on top of each wall; the top ends of the rafters meet at a ridge beam, but may butt directly to another rafter to form a pair of rafters called a couple. Depending on the roof covering material, either horizontal laths, battens, or purlins are fixed to the rafters. Heavier under purlins or purlin plates are used to support longer rafter spans.
Tie beams, which may serve as ceiling joists, are connected between the lower ends of opposite rafters to prevent them from spreading and forcing the walls apart. Collar beams or collar ties may be fixed higher up between opposite rafters for extra strength; the rafters, tie beams and plates serve to transmit the weight of the roof to the walls of the building Pre-manufactured roof trusses come in a wide variety of styles. They are designed by the manufacturer for each specific building. Timber trusses are built in a variety of styles using wood or metal joints. Heavy timber rafters spaced 8 feet to 12 feet apart are called principal rafters. Principal rafters may carry common purlins. Roof framing must be designed to hold up a structural load including what is called dead load, its own weight and the weight of the roof covering, additional loading called the environmental load such as snow and wind. Flat roofs may need to be designed for live loads if people can walk on them. In the United States, building codes specify the loads in pounds per square foot which vary by region.
The load and span defines the spacing of the rafters and trusses. The roofing material is designed to shed water; the covering is a major element of the architecture so roofing materials come in a wide variety of colors and textures. The primary roof covering on houses in North America are asphalt shingles, but some have other types of roof shingles or metal roofs. Tile and thatch roofs are more common in Europe than North America; some roofing materials help reduce air conditioning costs in hot climates by being designed to reflect light. Asphalt shingles is the most used roofing material in North America, making up as much as 75% of all steep slope roofs; this type of material is gaining popularity in Europe due to lower installation costs. Asphalt shingles dominate North American residential roofing market, because they are about half the price of other materials In the southern US and Mexico, clay tile roofs are very popular, due to their longevity, ability to withstand hurricane winds with minimal or no damage.
In Europe and tile roofs are popular. Many slate roofs in Europe are over 100 years old, require minimal maintenance / repairs. Roof space ventilation is needed to combat condensation within the roof space, leading to interstitial condensation within the roof fabric. Condensation within the roof space is much more of a problem today due to: much less fortuitous ventilation due to tighter building envelopes with high performance windows and door and no chimneys leading; this tighter envelope means the air temperature in buildings has risen, the warmer the air in the building is, the more water vapour the air can carry. As the occupied part of building has become warner, the roof space has become colder, with high performance insulation and roofing membranes leading to a cold roof space; when the warm, moist air from below rises into the cold roof space. Most building materials are permeable to water vapour.