Cement rendering is the application of a premixed layer of sand and cement to brick, stone, or mud brick. It is textured, colored, or painted after application, it is used on exterior walls but can be used to feature an interior wall. Depending on the'look' required, rendering can be fine or coarse, textured or smooth, natural or colored, pigmented or painted; the cement rendering of brick and mud houses has been used for centuries to improve the appearance of exterior walls. It can be seen in different forms all over southern Europe. Different countries have their own styles and traditional colors. Different finishes can be created by using different tools such as sponges, or brushes; the art in traditional rendering is the appearance of the top coat. Different tradesmen have different finishing styles and are able to produce different textures and decorative effects; some of these special finishing effects may need to be created with a thin finishing'top coat' or a finishing wash. Cement render consists of 6 parts clean sharp fine sand, 1 part cement, 1 part lime.
The lime reduces cracking when the render dries. Any general purpose cement can be used. Various additives can be added to the mix to increase adhesion. Coarser sand is used in the base layer and finer sand in the top layer; the application process resembles the process for applying paint. To ensure adhesion, the surface to be rendered is hosed off to ensure it is free of any dirt and loose particles. Old paint or old render is scraped away; the surface is roughened to improve adhesion. For large areas, vertical battens are fixed to the wall every 1 to 1.5 meters, to keep the render flat and even. There is a wide variety of premixed renders for different situations; some have a polymer additive to the traditional cement and sand mix for enhanced water resistance and adhesion. Acrylic premixed renders have strength, they can be used on a wider variety of surfaces than cement render, including concrete, cement blocks, AAC concrete paneling. With the right preparation, they can be used on smoother surfaces like cement sheeting, new high tech polymer exterior cladding such as Uni-Base, expanded polystyrene.
A few of these require activation with cement just prior to application. Some premixed. There are many various acrylic-bound pigmented'designer' finishing coats that can be applied over acrylic render. Various finishes and textures are possible such as sand, marble, stone chip, lime wash or clay like finishes. There are stipple, glistening finishes, those with enhanced water resistance and anti fungal properties. Depending upon the product, they can be troweled or sponged on. A limited number can be sprayed on. Acrylic renders take only 2 days to dry and cure—much faster than the 28 days for traditional render. A significant disadvantage of acrylic render vs. traditional rendering is that acrylic render lacks the sustainability and environmental compatibility of traditional cement-and-mineral render. All buildings have a finite lifetime, their materials will be either recycled or absorbed into the environment. Acrylic being a synthetic polymer material, it does not break down by natural weathering the way that a cement and lime mixture will, persisting in the natural environment for centuries as synthetic chemical compounds that have unknown long-term effects on ecosystems.
The application and drying process of acrylic resin render involves the atmospheric evaporation of pollutant solvents—necessary for the application of the resin—which are hazardous to the health of humans and of many organisms on which humans depend. Synthetic polymers such as acrylic are manufactured from chemical feedstocks such as acetone, hydrogen cyanide, ethylene and other petroleum derivatives; the polymer products cannot be recycled, so new raw materials, taken from the finite and diminishing supply of raw natural resources, must always be put into their manufacture, making the process unsustainable. Traditional cement-based render does not have these problems, making it an arguably better choice in many cases, despite its working limitations. Cement plaster Exterior insulation finishing system Harl Lath and plaster Pargeting Plaster Plasterwork Polished plaster Siding Stucco Tadelakt Reichel, Alexander. Plaster, Render and Coatings: Details, Case Studies
The cornerstone is the first stone set in the construction of a masonry foundation, important since all other stones will be set in reference to this stone, thus determining the position of the entire structure. Over time a cornerstone became a ceremonial masonry stone, or replica, set in a prominent location on the outside of a building, with an inscription on the stone indicating the construction dates of the building and the names of architect and other significant individuals; the rite of laying a cornerstone is an important cultural component of eastern architecture and metaphorically in sacred architecture generally. Some cornerstones include time capsules from, or engravings commemorating, the time a particular building was built; the ceremony involved the placing of offerings of grain and oil on or under the stone. These were the people of the land and the means of their subsistence; this in turn derived from the practice in still more ancient times of making an animal or human sacrifice, laid in the foundations.
Frazer in The Golden Bough charts the various propitiary sacrifices and effigy substitution such as the shadow, states that: Nowhere does the equivalence of the shadow to the life or soul come out more than in some customs practised to this day in South-eastern Europe. In modern Greece, when the foundation of a new building is being laid, it is the custom to kill a cock, a ram, or a lamb, to let its blood flow on the foundation-stone, under which the animal is afterwards buried; the object of the sacrifice is to give stability to the building. But sometimes, instead of killing an animal, the builder entices a man to the foundation-stone, secretly measures his body, or a part of it, or his shadow, buries the measure under the foundation-stone, it is believed. The Roumanians of Transylvania think that he whose shadow is thus immured will die within forty days. Not long ago there were still shadow-traders whose business it was to provide architects with the shadows necessary for securing their walls.
In these cases the measure of the shadow is looked on as equivalent to the shadow itself, to bury it is to bury the life or soul of the man, deprived of it, must die. Thus the custom is a substitute for the old practice of immuring a living person in the walls, or crushing him under the foundation-stone of a new building, in order to give strength and durability to the structure, or more in order that the angry ghost may haunt the place and guard it against the intrusion of enemies. Ancient Japan legends talk about Hitobashira, in which maidens were buried alive at the base or near some constructions as a prayer to ensure the buildings against disasters or enemy attacks. A VIP of the organization, or a local celebrity or community leader, will be invited to conduct the ceremony of figuratively beginning the foundations of the building, with the person's name and official position and the date being recorded on the stone; this person is asked to place their hand on the stone or otherwise signify its laying.
Still, until the 1970s, most ceremonies involved the use of a specially manufactured and engraved trowel that had a formal use in laying mortar under the stone. A special hammer was used to ceremonially tap the stone into place; the foundation stone has a cavity into, placed a time capsule containing newspapers of the day or week of the ceremony plus other artifacts that are typical of the period of the construction: coins of the year may be immured in the cavity or time capsule. Freemasons sometimes perform the public cornerstone laying ceremony for notable buildings; this ceremony was described by The Cork Examiner of 13 January 1865 as follows:... The Deputy Provincial Grand Master of Munster, applying the golden square and level to the stone said. After this, Bishop Gregg spread cement over the stone with a trowel specially made for the occasion by John Hawkesworth, a silversmith and a jeweller, he gave the stone three knocks with a mallet and declared the stone to be'duly and laid'. The Deputy Provincial Grand Master of Munster poured offerings of corn and wine over the stone after Bishop Gregg had declared it to be'duly and laid'.
The Provincial Grand Chaplain of the Masonic Order in Munster read out the following prayer:'May the Great Architect of the universe enable us as to carry out and finish this work. May He protect the workmen from danger and accident, long preserve the structure from decay. So mote it be.' The choir and congregation sang the Hundredth Psalm. In Freemasonry, which grew from the practice of stonemasons, the initiate is placed in the north-east corner of the Lodge as a figurative foundation stone; this is intended to signify the unity of the North associated with darkness and the East associated with light. A cornerstone will sometimes be referred to as a "foundation-stone", is symbolic of Christ, whom the Apostle Paul referred to as the "head of the corner" and is the "Chief Cornerstone of the Church". A chief or head cornerstone is placed above two wall
A keystone is the wedge-shaped stone piece at the apex of a masonry arch, or the round one at the apex of a vault. In both cases it is the final piece placed during construction and locks all the stones into position, allowing the arch or vault to bear weight. In both arches and vaults, keystones are enlarged beyond the structural requirements, decorated in some way. Keystones are placed in the centre of the flat top of openings such as doors and windows for decorative effect. Although a masonry arch or vault cannot be self-supporting until the keystone is placed, the keystone experiences the least stress of any of the voussoirs, due to its position at the apex. Old keystones can decay due to a condition known as bald arch. In a rib-vaulted ceiling, keystones may mark the intersections of two or more arched ribs. For aesthetic purposes, the keystone is sometimes larger than the other voussoirs, or embellished with a boss. Mannerist architects of the 16th century designed arches with enlarged and dropped keystones, as in the "church house" entrance portal at Colditz Castle.
Numerous examples are found in the work of Sebastiano Serlio, a 16th-century Italian Mannerist architect. Architectural sculpture Coping List of classical architecture terms Oculus compression ring Media related to keystones at Wikimedia Commons
A brick is building material used to make walls and other elements in masonry construction. Traditionally, the term brick referred to a unit composed of clay, but it is now used to denote any rectangular units laid in mortar. A brick can be composed of clay-bearing soil and lime, or concrete materials. Bricks are produced in numerous classes, types and sizes which vary with region and time period, are produced in bulk quantities. Two basic categories of bricks are non-fired bricks. Block is a similar term referring to a rectangular building unit composed of similar materials, but is larger than a brick. Lightweight bricks are made from expanded clay aggregate. Fired bricks are one of the longest-lasting and strongest building materials, sometimes referred to as artificial stone, have been used since circa 4000 BC. Air-dried bricks known as mudbricks, have a history older than fired bricks, have an additional ingredient of a mechanical binder such as straw. Bricks are laid in courses and numerous patterns known as bonds, collectively known as brickwork, may be laid in various kinds of mortar to hold the bricks together to make a durable structure.
The earliest bricks were dried brick, meaning that they were formed from clay-bearing earth or mud and dried until they were strong enough for use. The oldest discovered bricks made from shaped mud and dating before 7500 BC, were found at Tell Aswad, in the upper Tigris region and in southeast Anatolia close to Diyarbakir; the South Asian inhabitants of Mehrgarh constructed, lived in, airdried mudbrick houses between 7000–3300 BC. Other more recent findings, dated between 7,000 and 6,395 BC, come from Jericho, Catal Hüyük, the ancient Egyptian fortress of Buhen, the ancient Indus Valley cities of Mohenjo-daro and Mehrgarh. Ceramic, or fired brick was used as early as 3000 BC in early Indus Valley cities like Kalibangan; the earliest fired bricks appeared in Neolithic China around 4400 BC at Chengtoushan, a walled settlement of the Daxi culture. These bricks were made of red clay, fired on all sides to above 600 °C, used as flooring for houses. By the Qujialing period, fired bricks were being used to pave roads and as building foundations at Chengtoushan.
Bricks continued to be used during 2nd millennium BC at a site near Xi'an. Fired bricks were found in Western Zhou ruins; the carpenter's manual Yingzao Fashi, published in 1103 at the time of the Song dynasty described the brick making process and glazing techniques in use. Using the 17th-century encyclopaedic text Tiangong Kaiwu, historian Timothy Brook outlined the brick production process of Ming Dynasty China: "...the kilnmaster had to make sure that the temperature inside the kiln stayed at a level that caused the clay to shimmer with the colour of molten gold or silver. He had to know when to quench the kiln with water so as to produce the surface glaze. To anonymous labourers fell the less skilled stages of brick production: mixing clay and water, driving oxen over the mixture to trample it into a thick paste, scooping the paste into standardised wooden frames, smoothing the surfaces with a wire-strung bow, removing them from the frames, printing the fronts and backs with stamps that indicated where the bricks came from and who made them, loading the kilns with fuel, stacking the bricks in the kiln, removing them to cool while the kilns were still hot, bundling them into pallets for transportation.
It was hot, filthy work." Early civilisations around the Mediterranean adopted the use of fired bricks, including the Ancient Greeks and Romans. The Roman legions operated mobile kilns, built large brick structures throughout the Roman Empire, stamping the bricks with the seal of the legion. During the Early Middle Ages the use of bricks in construction became popular in Northern Europe, after being introduced there from Northern-Western Italy. An independent style of brick architecture, known as brick Gothic flourished in places that lacked indigenous sources of rocks. Examples of this architectural style can be found in modern-day Denmark, Germany and Russia; this style evolved into Brick Renaissance as the stylistic changes associated with the Italian Renaissance spread to northern Europe, leading to the adoption of Renaissance elements into brick building. A clear distinction between the two styles only developed at the transition to Baroque architecture. In Lübeck, for example, Brick Renaissance is recognisable in buildings equipped with terracotta reliefs by the artist Statius von Düren, active at Schwerin and Wismar.
Long-distance bulk transport of bricks and other construction equipment remained prohibitively expensive until the development of modern transportation infrastructure, with the construction of canal and railways. Production of bricks increased massively with the onset of the Industrial Revolution and the rise in factory building in England. For reasons of speed and economy, bricks were preferred as building material to stone in areas where the stone was available, it was at this time in London that bright red brick was chosen for construction to make the buildings more visible in the heavy fog and to help prevent traffic accidents. The transition from the traditional method of production known as hand-moulding to a mechanised form of mass-production took place during the first half of the nineteenth century; the first successful brick-making machine was patented by Henry Clayton, employed at the
A course is a layer of the same unit running horizontally in a wall. It can be defined as a continuous row of any masonry unit such as bricks, concrete masonry units, shingles, etc. Coursed masonry construction is that in which units are arranged in regular courses, not irregularly. On the other hand, coursed rubble masonry construction is that in which units of random size, that are not cut down, are used to build courses and the in-between spaces are filled with mortar or smaller stones. If a course is the horizontal arrangement a wythe is the vertical section of a wall. A standard 8-inch CMU block is equal to three courses of brick, so, it easy to build a brick-on-CMU wall. A bond pattern is the arrangement of several courses; the types of bond patterns can be found under Brickwork. When building a masonry wall the corners are first built and the spaces between them are filled by the remaining courses. Masonry coursing can be arranged in various orientations, according to which side of the masonry is facing the outside and how it is positioned.
Stretcher: Units are laid horizontally with their longest end parallel to the face of the wall. This orientation can display the bedding of a masonry stone. Header: Units are laid on their widest edge so that their shorter ends face the outside of the wall, they tie them together. Rowlock: Units laid on their narrowest edge so their shortest edge faces the outside of the wall; these are used for garden walls and for sloping sills under windows, however these are not climate proof. Soldier: Units are laid vertically on their shortest ends so that their narrowest edge faces the outside of the wall; these are used for window tops of walls. Sailor: Units are laid vertically on their shortest ends with their widest edge facing the wall surface. Shiner or rowlock stretcher: Units are laid on the long narrow side with the broad face of the brick exposed; this orientation can display fossils within a masonry stone. Different patterns can be used in different parts of a building, some decorative and some structural.
Stretcher Course: This is a course made up of a row of stretchers. This is the simplest arrangement of masonry units. If the wall is two wythes thick, one header is used to bind the two wythes together. Header Course: This is a course made up of a row of headers. Bond Course: This is a course of headers that bond the facing masonry to the backing masonry. String Course: A horizontal row of masonry, narrower than the other courses, that extends across the façade of a structure or wraps around decorative elements like columns; this is decorative. Sill course: Stone masonry courses at the windowsill, projected out from the wall. Split course: Units are cut down so they are smaller than their normal thickness. Springing Course: Stone masonry on which the first stones of an arch rest. Starting Course: The first course of a unit referring to shingles. Case Course: Units form the foundation or footing course, it is the lowest course in a masonry wall used for multiple functions structural. Barge Course: Units form the coping of a wall by bricks set on edge
Rubble masonry is rough, unhewn building stone set in mortar, but not laid in regular courses. It may appear as the outer surface of a wall or may fill the core of a wall, faced with unit masonry such as brick or cut stone. Snecked masonry - Masonry made of mixed sizes of stone but in regular courses