Types of Bricks – Detail Classification of Bricks

Bricks are a regular size rectangular unit. Bricks are made of clay. They are usually used for most of the building works. Bricks are most generally used as a substitute for stone when the stone is not available.

Types of Bricks

Bricks can be of many types depending on –

1. Quality
2. Building Process
3. Manufacturing Method
4. Raw Material
5. Using Location 
6.  Weather-resisting Capability
7. Purpose of Using 
8. Shape 
9. Region

Classification of Bricks Based on Quality

On the basis of quality, Bricks are of the following kinds:

1. First Class Brick: The size is standard. The color of these bricks is uniform yellow or red. It is well burnt, regular texture, uniform shape. The absorption capacity is less than 10%, crushing strength is, 280kg/cm² (mean) where it is 245 kg/cm² (minimum). It doesn’t have efflorescence. It emits a metallic sound when struck by another similar brick or struck by a hammer. It is hard enough to resist any fingernail expression on the brick surface if one tries to do with a thumbnail. It is free from pebbles, gravels or organic matters. It is generally used-
   • in a building of long durability, say 100 years
   • for building exposes to a corrosive environment;
   • for making coarse aggregates of concrete.
2. Second Class Brick: The size is standard, color is uniform yellow or red. It is well burnt, slightly over burnt is acceptable. It has a regular shape; efflorescence is not appreciable. The absorption capacity is more than 10% but less than 15%. Crushing strength is 175kg/cm²(mean) where the minimum is 154 kg/cm². It emits a metallic sound when struck by another similar brick or struck by a hammer. It is hard enough to resist any fingernail expression on the brick surface if one tries to do with a thumbnail. It is used for the construction of one-storied buildings, temporary shed when intended durability is not more than 15 years. 
3. Third Class Brick: The shape and size are not regular. The color is soft and light red colored. It is under burnt, slightly over burnt is acceptable. It has extensive efflorescence. The texture is non-uniform. The absorption capacity is more than 15% but less than 20%. The crushing strength is 140kg/cm²(mean) where the minimum crushing strength is 105kg/cm². It emits a dull or blunt sound when struck by another similar brick or struck by a hammer. It leaves fingernail expression when one tries to do with the thumbnail.

Classification of Bricks Based on Building Process

On the basis of the building process Bricks are of following kinds:

1. Unburnt Bricks: These are half burnt bricks. The color is yellow. The strength is low. They are used as surki in lime terracing. They are used as soiling under RCC footing or basement. Such bricks should not be exposed to rainwater.
2. Burnt Bricks: Burnt bricks are made by burning them in the kiln. First class, Second Class, Third Class bricks are burnt bricks. 
3. Over Burnt or Jhama Brick: It is often known as the vitrified brick as it is fired at high temperature and for a longer period of time than conventional bricks. As a result, the shape is distorted. The absorption capacity is high. The strength is higher or equivalent to first class bricks. It is used as lime concrete for the foundation. It is also used as coarse aggregate in the concrete of slab and beam which will not come in contact with water.

Classification of Bricks Based on Manufacturing Method

On the basis of manufacturing method bricks are of the following kinds:

1. Extruded Brick: It is created by forcing clay and water into a steel die, with a very regular shape and size, then cutting the resulting column into shorter units with wires before firing. It is used in constructions with limited budgets. It has three or four holes constituting up to 25% volume of the brick.
2. Molded Brick: It is shaped in molds by hand rather being in the machine. Molded bricks between 50-65mm are available instantly. Other size and shapes are available in 6-8 weeks after the order.
3. Dry pressed Brick: It is the traditional types of bricks which are made by compressing clay into molds. It has a deep frog in one bedding surface and shallow frog in another.

Classification of Bricks Based on Raw Materials

On the basis of raw materials bricks are of the following kinds:

1. Burnt Clay Brick: It is obtained by pressing the clay in molds and fried and dried in kilns. It is the most used bricks. It requires plastering when used in construction works. 
2. Fly ash clay Brick: It is manufactured when fly ash and clay are molded in 1000 degree Celsius. It contains a high volume of calcium oxide in fly ash. That is why usually described as self-cementing. It usually expands when coming into contact with moisture. It is less porous than clay bricks. It proved a smooth surface so it doesn’t need plastering.
3. Concrete Brick: It is made of concrete. It is the least used bricks. It has low compression strength and is of low quality. These bricks are used above and below the damp proof course. These bricks are used can be used for facades, fences and internal brickworks because of their sound reductions and heat resistance qualities. It is also called mortar brick. It can be of different colors if the pigment is added during manufacturing. It should not be used below ground. 
4. Sand-lime Brick: Sand, fly ash and lime are mixed and molded under pressure. During wet mixing, a chemical reaction takes place to bond the mixtures. Then they are placed in the molds. The color is greyish as it offers something of an aesthetic view. It offers a smoother finish and uniform appearance than the clay bricks. As a result, it also doesn’t require plastering. It is used as a load bearing members as it is immensely strong. 
5. Firebrick: It is also known as refractory bricks. It is manufactured from a specially designed earth. After burning, it can withstand very high temperature without affecting its shape, size, and strength. It is used for the lining of chimney and furnaces where the usual temperature is expected to be very high.

Classification of Bricks Based on Using Location

On the basis of using location bricks are of the following kinds:

1. Facing Brick: The façade material of any building is known as facing brick. Facings bricks are standard in size, are stronger than other bricks and also have better durability. The color is red or brown shades to provide a more aesthetic look to the building. There are many types of facing bricks which use different techniques and technology. Facing bricks should be weather resistant as they are most generally used on the exterior wall of buildings. 
2. Backing Brick: These types of brick don’t have any special features. They are just used behind the facing bricks to provide support.

Classification of Bricks Based on Weather-resisting Capability

On the basis of weather-resisting capability bricks are of following kinds:

1. Severe Weather Grade: These types of bricks are used in the countries which are covered in snow most of the time of year. These bricks are resistant to any kind of freeze-thaw actions.
2. Moderate Weather Grade: These types of bricks are used in tropical countries. They can withstand any high temperature. 
3. No Weather Grade: These bricks do not have any weather resisting capabilities and used on the inside walls.

Classification of Bricks Based on Their Using

There are many uses of bricks. On the basis of the purpose of their using bricks are of the following kinds:

1. Common Bricks: These bricks are the most common bricks used. They don’t have any special features or requirements. They have low resistance, low quality, low compressive strength. They are usually used on the interior walls.
2. Engineering Bricks: These bricks are known for many reasons. They have high compressive strength and low absorption capacity. They are very strong and dense. They have good load bearing capacity, damp proof, and chemical resistance properties. They have a uniform red color. They are classified as Class A, class B, class C. Class A is the strongest but Class B is most used. They are used for mainly civil engineering works like sewers, manholes, ground works, retaining walls, damp proof courses, etc.

Classification of Bricks Based on Shape

On the basis of shape bricks are of following kinds:

1. Bullnose Brick: These bricks are molded into round angles. They are used for rounded quoin.
2. Airbricks: These bricks contain holes to circulate air. They are used on suspended floors and cavity walls.
3. Channel Bricks: They are molded into the shape of a gutter or channel. They are used in drains. 
4. Coping Bricks: They can be half round, chamfered, Saddleback, angled varied according to the thickness of the wall.
5. Cow Nose Bricks: Bricks having double bullnose known as Cow Nose Bricks.
6. Capping Bricks: These bricks are used to cap the tops of parapets or freestanding walls. 
7. Brick Veneers: These bricks are thin and used for cladding.
8. Curved Sector Bricks: These are curved in shape. They are used in arcs, pavements, etc.
9. Hollow Bricks: These bricks are around one-third of the weight of the normal bricks. They are also called cellular or cavity bricks. Their thickness is from 20-25mm. These bricks pave the way to quicker construction as they can be laid quickly compared to the normal bricks. They are used in partitioning. 
10. Paving Bricks: These bricks contain a good amount of iron. Iron vitrifies bricks at low temperature. They are used in garden park floors, pavements. These bricks withstand the abrasive action of traffic thus making the floor less slippery. 
11. Perforated Bricks: These bricks contain cylindrical holes. They are very light in weight. Their preparation method is also easy. They consume less clay than the other bricks. They can be of different shapes like round, square, rectangular. They are used in the construction of the panels for lightweight, structures, and multistoried frame structures. 
12. Purpose Made Bricks: For specific purposes, these bricks are made. Splay and can’t bricks are made for doors and window jambs. Engineering bricks are made for civil engineering constructions such as sewers, manholes, retaining walls. Fire bricks are made for chimneys and fireworks. Ornamental bricks are made to use for cornices, corbels. Arch bricks are used in arcs.

Classification of Bricks Based on Region

On the basis of the region bricks are of following kinds:

1. Cream City Bricks: These bricks are from Milwaukee, Wisconsin. 
2. London Stock: These bricks are used in London.
3. Dutch: These are from the Netherlands.
4. Nanak Shahi Bricks: These are from India. 
5. Roman: These are used in Roman constructions, 
6. Staffordshire Blue Brick: These are from England.