Engineering Bricks

Engineering bricks differ from facing bricks in their use and application. While facing bricks are typically used as the external façade of a building, engineering bricks are used where strength and resistance to moisture absorption are the primary requirement. You will find engineering bricks used in retaining walls and other ground works courses where the wall will be supporting weight or resisting external pressures. Engineering bricks are made through the process of extrusion, where the brick material is forced through a form and cut into the appropriate lengths with a cutting wire.

Choosing the right Type of Engineering Brick

In almost all building projects you will find one of two classes of engineering bricks used. They are designated as” Class A” or “Class B”, the primary difference being in compressive strength and cost.

Class B Bricks

Class B bricks are the most popular and commonly used engineering bricks. They are almost always red in colour. The key technical specifications for class B bricks are a compressive strength of 75N/mm² or greater, with a water absorption rate of less than or equal to 7%. Of the two classes of engineering bricks, class B bricks are the least costly of the two.

Class A Bricks

Class A bricks will usually be blue in colour as a result of the higher firing temperature used in their construct. They are less porous and stronger than class B bricks but are also higher priced. Compressive strength of class A bricks is equal to, or greater than 125N/mm² with a water absorption rate of less than 4.5%.


When choosing engineering bricks it is important to note that these types of bricks are made for strength and resistance to water absorption and will not have been inspected for minor chips or surface blemishes. Variation in the colour of the bricks can also be expected. In applications where a more rustic or worn look is wanted, engineering bricks can be used in lieu of facing bricks where contrast in the façade of a brick clad building is desired.

Choosing the right style and class of brick is something you may want to do with the help of a professional who is experienced in the different options and applications. If you are considering bricks for your building project, the staff at Building Materials Online will be happy to explain in more detail the specifications of different bricks and other building materials. We are standing by, so call or e-mail us with your questions regarding engineering bricks.