Bricks are one of mankind's oldest building materials, probably dating from the time someone threw mud into a fire and discovered it became rock hard and suitable for making things. Traditional bricks are made of clay, once formed by hand of whatever earth was handy. The type of clay determined the type and quality of the brick. Today's bricks are made by machines and fired in giant kilns, with clay standards and special additives.
There are three basic types of brick: building, face and paver. All are made with some type of clay, but with different size, colour and durability characteristics to suit various applications. Building bricks are used to build walls or elements intended to support structures. Face bricks are more decorative, to provide an attractive finish to the outside of a wall. Pavers are designed for walks and paving.
The type of clay used will determine the hardness, durability and colour of bricks. Red clay bricks, the most common type, get their colour from iron content; the more iron, the deeper the colour. The intensity of the firing heat also can affect the colour; very high temperatures will produce a darker shade. Adding other elements, such as manganese, silica, lime or alkali, will make colours ranging from yellow and cream to almost black. Some bricks have uniform colour throughout; others have slight variations of shade, depending on the clay and the brick formation.
Common clay bricks are traditionally some shade of red. The traditional size is called nominal and is 2-by-4-by-8-inches, though actually slightly smaller because the nominal size allows for mortar. Common clay bricks are used to build walls and other structures and also can be used as facing or as paving for patios and sidewalks. Some varieties have manufacturer names or other information moulded into one wide face. Basic construction bricks often have two or three holes to lower the weight and add space for securing mortar.
Face bricks are designed to present an attractive surface on the outside of a building or wall. They typically have one 2-inch edge or face intended to be placed toward the outside. Many have special surface treatments, rough edges called "struck face." Some face bricks will have different colours or looks and may have an almost ceramic or shiny look with the addition of special clay on one side. Face bricks often are more uniform in colour and size but also can have variations in size and shape to create different looks. Some styles are longer, for instance.
All bricks are rated for their intended use, including such factors as resistance to weather, ability to support weight, absorption of moisture, resistance to abrasion. FBS (Face Brick Standard) is for general use with variations in size and colour permitted; FBX (Face Brick Extra) is similar but with minimal size and colour variation allowed. NFP (Non-Facing Plastered) is for construction that will be covered with other facing. Types I, II and III are specifically for various paving applications..