The term brick refers to small units of building material, often made from fired clay and secured with mortar, a bonding agent comprising of cement, sand, and water. Long a popular material, brick retains heat, with-stands corrosion, and resists fire. Because each unit is small—usually four inches wide and twice as long, brick is an ideal material for structures in confined spaces, as well as for curved designs. Moreover, with minimal upkeep, brick buildings generally last a long time.

For the above-cited practical reasons and because it is also an aesthetically pleasing medium, brick has been used as a building material for at least 5,000 years. The first brick was probably made in the Middle East, between the Tigris and Euphrates rivers in what is now Iraq. Lacking the stone their contemporaries in other regions used for permanent structures, early builders here relied on the abundant natural materials to make their sun-baked bricks. These, however, were of limited use because they lacked durability and could not be used outdoors; exposure to the elements caused them to disintegrate. The Babylonians, who later dominated Mesopotamia, were the first to fire bricks, from which many of their tower-temples were constructed.

From the Middle East the art of brickmaking spread west to what is now Egypt and east to Persia and India. Although the Greeks, having a plentiful supply of stone, did not use much brick, evidence of brick kilns and structures remains throughout the Roman Empire. However, with the decline and fall of Rome, brickmaking in Europe soon diminished. It did not resume until the 1200s, when the Dutch made bricks that they seem to have exported to England. In the Americas, people began to use brick during the sixteenth century. It was the Dutch, however, who were considered expert craftsmen.

Prior to the mid-1800s, people made bricks in small batches, relying on relatively inefficient firing methods. One of the most widely used was an open clamp, in which bricks were placed on a fire beneath a layer of dirt and used bricks. As the fire died down over the course of several weeks, the bricks fired. Such methods gradually became obsolete after 1865, when the Hoffmann kiln was invented in Germany. Better suited to the manufacture of large numbers of bricks, this kiln contained a series of compartments through which stacked bricks were transferred for pre-heating, burning, and cooling.

Brickmaking improvements have continued into the twentieth century. Improvements include rendering brick shape absolutely uniform, lessening weight, and speeding up the firing process. For example, modern bricks are seldom solid. Some are pressed into shape, which leaves a frog, or depression, on their top surface. Others are extruded with holes that will later expedite the firing process by exposing a larger amount of surface area to heat. Both techniques lessen weight without reducing strength.

However, while the production process has definitely improved, the market for brick has not. Brick does have the largest share of the opaque materials market for commercial building, and it continues to be used as a siding material in the housing industry. However, other siding materials such as

To produce brick, the raw materials are first crushed and ground in a jaw crusher. Next, the ingredients are formed using one of several methods. In extrusion, the pulverized ingredients are mixed togther with water, passed into a de-airing chamber (which removes the air to prevent cracking), compacted, and extruded out of a die of the desired shape.
wood, stucco, aluminum, plaster, and vinyl are strong competitors because they cost up to 50 percent less, and some (notably stucco and plaster) offer built-in insulation. Yet these systems can cost up to 1.75 times that of brick, which also requires less maintenance. Other materials that compete with brick despite their usually higher cost include precast concrete panels, glass, stone, artificial stone, concrete masonry, and combinations of these materials, because advances in manufacturing and design have made such materials more attractive to the builder. According to the U.S. Industrial Outlook, the use of brick as a siding material for single-family homes dropped from 26 percent in 1984 to 17 percent in 1989.

Raw Materials

Natural clay minerals, including kaolin and shale, make up the main body of brick. Small amounts of manganese, barium, and other additives are blended with the clay to produce different shades, and barium carbonate is used to improve brick's chemical resistance to the elements. Many other additives have been used in brick, including byproducts from papermaking, ammonium compounds, wetting agents, flocculents (which cause particles to form loose clusters) and deflocculents (which disperse such clusters). Some clays require the addition of sand or grog (pre-ground, pre-fired material such as scrap brick).

A wide variety of coating materials and methods are used to produce brick of a certain color or surface texture. To create a typical coating, sand (the main component) is mechanically mixed with some type of colorant. Sometimes a flux or frit (a glass containing colorants) is added to produce surface textures. The flux lowers the melting temperature of the sand so it can bond to the brick surface. Other materials including graded fired and unfired brick, nepheline syenite, and graded aggregate can be used as well.

The Manufacturing

The initial step in producing brick is crushing and grinding the raw materials in a separator and a jaw crusher. Next, the blend of ingredients desired for each particular batch is selected and filtered before being sent on to one of three brick shaping processes—extrusion, molding, or pressing, the first of which is the most adaptable and thus the most common. Once the bricks are formed and any subsequent procedures performed, they are dried to remove excess moisture that might otherwise cause cracking during the ensuing firing process. Next, they are fired in ovens and then cooled. Finally, they are dehacked—automatically stacked, wrapped with steel bands, and padded with plastic corner protectors.

Grinding, sizing, and combining
raw materials


Chamfering the brick




Setting and packaging

Quality Control

Though the brick industry is often considered unsophisticated, many manufacturers are participating in total quality management and statistical control programs. The latter involves establishing control limits for a certain process (such as temperature during drying or firing) and tracking the parameter to make sure the relevant processes are kept within the limits. Therefore, the process can be controlled as it happens, preventing defects and improving yields.

A variety of physical and mechanical properties must be measured and must comply with standards set by the American Society of Testing and Materials (ASTM). These properties include physical dimensions, density, and mechanical strength. Another important property is freeze-thaw durability, where the brick is tested under conditions that are supposed to simulate what is encountered in the outdoors. However, current tests are inadequate and do not really correlate to actual conditions. What passes in the laboratory may not pass in the field. Therefore, the brick industry is trying to develop a more accurate test.

A similar problem exists with a condition known as efflorescence, which occurs when water dissolves certain elements (salt is among the most common) in exterior sources, mortar, or the brick itself. The residual deposits of soluble material produce surface discoloration that can be worsened by improper cleaning. When salt deposits become insoluble, the efflorescence worsens, requiring extensive cleaning. Though a brick may pass the laboratory test, it could fail in the field due to improper design or building practices. Therefore, brick companies are developing their own in-house testing procedures, and research is continuing to develop a more reliable standard test.

The Future

Currently, the use of brick has remained steady, at around seven to nine billion a year, down from the 15 billion used annually during the early 1900s. In an effort to increase demand, the brick industry continues to explore alternative markets and to improve quality and productivity. Fuel efficiency has also improved, and by the year 2025 brick manufacturers may even be firing their brick with solar energy. However, such changes in technology will occur only if there is still a demand for brick.

Even if this demand continues, the brick industry both here and abroad faces another challenge: it will soon be forced to comply with environmental regulations, especially in the area of fluorine emissions. Fluorine, a byproduct of the brickmaking process, is a highly reactive element that is dangerous to humans. Long-term exposure can cause kidney and liver damage, digestive problems, and changes in teeth and bones, and the Environmental Protection Agency (EPA) has consequently established maximum exposure limits. To lessen the dangers posed by fluorine emissions, brickworks can install scrubbers, but they are expensive. While some plants have already installed such systems, the U.S. brick industry is trying to play a more important role in developing less expensive emissions testing methods and establishing emission limits. If the brick industry cannot persuade federal regulators to lower their requirements, it is quite possible that the industry could shrink in size, as some companies cannot afford to comply and will go out of business.

Where To Learn More


Bender, Willi and Frank Handle. Brick and Tile Making. Bauverlag GmbH, 1985.


Robinson, Gilbert C. Ceramics and Glasses. ASM International, 1992, pp. 943-950.


"Trends in Brick Plant Operations," The American Ceramic Society Bulletin. 1992, pp. 69-74.

Hall, Alvin. "Using Computer-Aided Manufacturing to Build Better Brick," The American Ceramic Society Bulletin. 1990, pp. 80-82.

Richards, Robert W. "Brick Manufacturing from Past to Present," The American Ceramic Society Bulletin. May, 1990, pp. 807-813.

Sheppard, Laurel M. "Making Brick and Meeting Regulations," The American Ceramic Society Bulletin. 1993.

"Lodge Lane Brickworks: A Breakthrough in the Reduction Firing of Bricks," Ziegelindustrie. September, 1992, pp. 344-341.

L S. Millberg

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Aug 9, 2009 @ 11:11 am
Thank U 4 the well researched info. May add me on yo e-mailing list.
I would like 2 know the type of clay used when making face brick.
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Jan 30, 2010 @ 2:02 am
basically by reading the above article i am somewhat diverted from my buisness idea.
Actually i was on a way of designing a brick manufacturing plant.I think so this buisness won't be feasible as enivromental norms would be strict furthur & to overcome that enivromental norms I have to put up all my profits in that.ok am i thinking correctly or am i wrong please give feedback if any body is in same thinking before me.
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Jun 22, 2011 @ 6:06 am
I want general information about the terms of the burnt bricks
1 - types of bricks
2 - method of manufacture of burnt bricks
3 - method of manufacture of the misdeeds of burnt bricks
4 - Specifications burnt bricks
