Brick, Brick

Being much more resistant to cold and moist weather conditions, brick enabled the construction of permanent buildings in regions where the harsher climate precluded the use of mud bricks.

The use of bricks in Southern and Western Germany, for example, can be traced back to traditions already described by the Roman architect Vitruvius.

Brook, 19–20 Early descriptions of the production process and glazing techniques used for bricks can be found in the Song Dynasty carpenter's manual Yingzao Fashi , published in 1103 by the government official Li Jie, who was put in charge of overseeing public works for the central government's construction agency. The historian Timothy Brook writes of the production process in Ming Dynasty China (aided with visual illustrations from the Tiangong Kaiwu encyclopedic text published in 1637): in Iran displays 12th century craftsmanship ...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 also had to know when to quench the kiln with water so as to produce the surface glaze. To anonymous laborers 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 standardized wooden frames (to produce a brick roughly 42 cm long, 20 cm wide, and 10 cm thick), 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 (likelier wood than coal), stacking the bricks in the kiln, removing them to cool while the kilns were still hot, and bundling them into pallets for transportation. It was hot, filthy work. Brook, 20–21.

It culminated in the so-called brick Gothic, a reduced style of Gothic architecture that flourished in Northern Europe, especially in the regions around the Baltic Sea which are without natural rock resources. Brick Gothic buildings, which are built almost exclusively of bricks, are to be found in Denmark, Germany, Poland and Russia.

It was only during the mid-18th century that visible brick walls regained some degree of popularity, as illustrated by the Dutch Quarter of Potsdam, for example.

Before this time bricks were generally made close to their point of intended use. It has been estimated that in England in the eighteenth century carrying bricks by horse and cart for ten miles (16 km) over the poor roads then existing could more than double their price.

The buildings of the Industrial Revolution in Britain were largely constructed of brick and timber due to the demand created. During the building boom of the nineteenth century in the eastern seaboard cities of Boston and New York, for example, locally made bricks were often used in construction in preference to the brownstones of New Jersey and Connecticut for these reasons.

Brick was revived for high structures in the 1950s following work by the Swiss Federal Institute of Technology and the Building Research Establishment in Watford, UK. This method produced eighteen story structures with bearing walls no thicker than a single brick (150-225 mm). This potential has not been fully developed because of the ease and speed in building with other materials, in the late-20th century brick was confined to low- or medium-rise structures or as a thin decorative cladding over concrete-and-steel buildings or for internal non-load bearing walls.

The bricks often have added lime, ash, and organic matter to speed the burning.

The most common type of brick kiln in use there are Bull's Trench Kiln (BTK), based on a design developed by British engineer W. Bull in the late nineteenth century.

This is forced through a die to create a long cable of material of the proper width and depth. This is then cut into bricks of the desired length by a wall of wires. Most structural bricks are made by this method, as hard dense bricks result, and holes or other perforations can be produced by the die. The introduction of holes reduces the needed volume of clay through the whole process, with the consequent reduction in cost. The bricks are lighter and easier to handle, and have thermal properties different from solid bricks. The cut bricks are hardened by drying for between 20 and 40 hours at 50-150 C before being fired. The heat for drying is often waste heat from the kiln.

The finished bricks are very accurate and uniform, although the sharp arrises need careful handling to avoid damage to brick (and brick-layer). The bricks can be made in a variety of colours, white is common but pastel shades can be achieved.

For example pink coloured bricks are the result of a high iron content, white or yellow bricks have a higher lime content. Most bricks burn to various red hues, if the temperature is increased the colour moves through dark red, purple and then to brown or grey at around 1300 C. Calcium silicate bricks have a wider range of shades and colours, depending on the colourants used. The names of bricks may reflect their origin and colour, such as London Red and Cambridgeshire White.

They are made from a dry, small aggregate concrete which is formed in steel moulds by vibration and compaction in either an "egglayer" or static machine. The finished blocks are cured rather than fired using low-pressure steam. Concrete blocks are manufactured in a much wider range of shapes and sizes than clay bricks and are also available with a wider range of face treatments - a number of which are to simulate the appearance of clay bricks.

Subsequent reheating in the kiln fuses the slip into a glazed surface integral with the brick base.

They are very durable and considered more handsome than clay bricks by some. Only a few stones are suitable for bricks.

In most cases, the length of a brick is about twice its width, about eight inches (about 200 mm) or slightly more. This allows bricks to be laid bonded in a structure to increase its stability and strength (for an example of this, see the illustration of bricks laid in English bond , at the head of this article. The wall is built using alternating courses of stretchers , bricks laid longways and headers , bricks laid crossways. The headers tie the wall together over its width.

In the United Kingdom, the usual ("work") size of a modern brick is 215 102.5 65 mm (about 8.5 4 2.5 inches), which, with a nominal 10 mm mortar joint, forms a "coordinating" or fitted size of 225 112.5 75 mm, for a ratio of 6:3:2.

The density of solid clay bricks is around 2,000 kg/m: this is reduced by frogging, hollow bricks, etc.; but aerated autoclaved concrete, even as a solid brick, can have densities in the range of 450850 kg/m.

Blocks may be solid, cellular or hollow The term "frog" for the indentation on one bed of the brick is a word that often excites curiosity as to its origin.

In England clay bricks can have strengths of up to 100 MPa, although a common house brick is likely to show a range of 2040 MPa.

In the USA, brick pavement was found incapable of withstanding heavy traffic, but it is coming back into use as a method of traffic calming or as a decorative surface in pedestrian precincts. For example, in the early 1900s, most of the streets in the city of Grand Rapids, Michigan were paved with brick.

They have various uses, especially refractory bricks such as silica, magnesia, chamotte and neutral (chromomagnesite) refractory bricks. This type of brick must have good thermal shock resistance, refractoriness under load, high melting point, and satisfactory porosity. There is a large refractory brick industry, especially in the United Kingdom, Japan and the United States.

Although many houses in the UK are now built using a mixture of concrete blocks and other materials, many houses are skinned with a layer of bricks on the outside for aesthetic appeal.

Source: Wikipedia > Brick