Brick is a solid building material, commonly used to build walls or other structures. It is formed from clay or other mixtures and then fired (or baked) in a kiln. It is a durable building material that resists fire, rot, and weathering.

The term brick originated in the Middle French word brique, which is related to the Latin word bricus, meaning “broken piece”. It has been compared to Middle Dutch bricke, meaning “to break” or “to splinter”.

Today, the name brick refers to any stone- or clay-based building unit that is pressed together with cementitious mortar and then set in place to form a wall or other structure. There are thousands of different types, based on their size, forming method, origin, quality, texture and/or materials.

Common types of brick include:

soft mud dry press extruded
The earliest bricks were formed from hand-moulded mud and then dried in the sun. This process is still used today, though it is now more common to produce bricks in factory-style kilns rather than by hand.

Choosing the right type of brick is critical to ensure that it performs as intended. The correct brick will depend on the application, such as if it is for structural support or as an ornamental element. It will also have to be the right colour, surface texture, density, weight, absorption, pore structure, thermal characteristics, and fire resistance.

A brick may be perforated, which has holes drilled through it; cellular, which has indentations on one face of the brick; or hollow, which has holes that extend to a depth of more than 25% of its volume. Alternatively, it may have an indentation known as a “frog” that must be filled with mortar before the brick is laid.

Most bricks are made by combining clay with a small amount of sand and water in a mould. There are a variety of ways to make the brick mixture; the most popular methods are soft mud and dry-press.

The most efficient way to fire the brick is in a BTK, or a box kiln. These kilns contain several chambers that are linked by passages to gradually increasing temperatures until the entire kiln is at optimum firing and cooling.

This method has a number of advantages, including higher efficiency and less energy waste. A typical BTK kiln uses only 10% of the energy of a conventional kiln.

Another advantage is that the air reheats in a BTK, which saves fuel costs. The heated air is then re-used to pre-heat and dry the bricks.

Modern bricks may be produced from a variety of materials, including limestone, sand, and concrete. These are often referred to as’special’ or ‘engineering’ bricks, because they have particularly high strength and are often used in civil engineering applications.

Some bricks are manufactured with a special mix of sand and clay that has been formulated to improve specific characteristics. For example, sand-lime bricks are usually used for fireproof construction and have a strong, durable finish. They have low water absorption, good acid resistance, and excellent strength. Fly ash is another common ingredient for making sand-lime bricks.