Ever Wonder What Bricks Are Made Of? (2024)

Home Improvement

Burnt Clay, Concrete, Sun-Dried, and More

• 01 of 07

  Burnt Clay Bricks

  

  Burnt clay brick is one of the very oldest building materials found in many of the ancient structures of the world. Classic burnt clay bricks are created by pressing wet clay into molds, then drying and firing them in kilns. In appearance, these bricks are solid blocks of hardened clay and usually reddish.

  Burnt clay bricks are typically sold in four classes. First-class burnt-clay bricks are the finest, offering the best quality and strength. These high-grade burnt clay bricks have no noticeable flaws and cost more than lower classes.

  When burnt clay bricks are used in walls, they require plastering or rendering with mortar. Uses for burnt clay bricks include masonry walls, foundations, and columns.

• 02 of 07

  Sun-Dried Clay or Mud Bricks

  

  Sun-dried clay bricks, also known as mud bricks, are one of the oldest styles of bricks, but also the least durable. Sun-dried bricks are made by putting mud into a form and baking them in the sun. When the loaves of mud are dry, they are stacked and held together with more mud. Classic adobe-style homes are made with extremely thick walls constructed of mud brick.

  See Also

  The Colors of Brick

• 03 of 07

  Sand Lime Bricks

  

  Sand lime bricks (calcium silicatebricks) are made by mixing sand, fly ash, and lime. Pigments may also be added for color. The mixture is then molded under pressure to form bricks. Sand lime bricks are not fired in kilns in the same manner as burnt clay bricks; instead, the materials bond together by a chemical reaction that occurs as the wet bricks dry under heat and pressure. Sand lime bricks offer advantages such as:

  • Their uniform shape presents a smoother finish that doesn’t require plastering.
  • They offer excellent strength for load-bearing structures.
  • They are gray instead of the standard reddish color. Different pigments can be added for ornamental purposes.
  • Less mortar is required during construction.
  • Edges are straight and precise, making construction easier.
  • They do not effloresce salts and minerals.

  Sand lime bricks are often used in structural foundations and walls, exposed brick and pillars, and, when the pigment is added, for ornamental uses.

• 04 of 07

  Engineering Bricks

  

  Engineering bricks are used primarily in civil projects where strength and resilience against the elements are essential. They are clay-based and can be mixed with many other materials.

  What sets engineering bricks apart from other types is their extreme durability: They are fired at extremely high temperatures to produce a brick as hard as iron. They also have very low porosity and are used in places like sewers, retaining walls, manholes, foundational work, and underground tunnels, where resistance to water and frost is crucial. They come in two classes, A and B, with A offering higher compression strength and lower water absorption for the toughest conditions.

  Continue to 5 of 7 below

• 05 of 07

  Concrete Bricks

  

  Concrete bricks are made from solid concrete poured into molds. They are traditionally used in internal brickwork but are more frequently used in exterior work, such as facades and fences, to provide a modern or urban aesthetic. Concrete bricks can be manufactured in different colors if pigments are added during production.

  Due to their durability, concrete bricks can be used in almost any construction except underground since they tend to be porous.

• 06 of 07

  Fly Ash Clay Bricks

  

  Fly ash clay bricks are manufactured with clay and fly ash—a byproduct of coal burning—fired at about 1,832 degrees Fahrenheit. This type of brick is sometimes described as self-cementing since it contains a high volume of calcium oxide and expands when exposed to moisture. This tendency to expand, however, can also produce pop-out failure. Fly ash clay brick has the advantage of being lighter in weight than clay or concrete brick.

  Typical uses for fly ash clay brick include:

  • Structural walls
  • Foundations
  • Pillars
  • Anywhere that improved fire resistance is required

• 07 of 07

  Fire Bricks

  

  A fire brick, also called refractory brick, is used to line very hot areas. Fire bricks are fired at extremely high temperatures and specially formulated with silica and a high aluminum oxide content to withstand excessive heat for use in places that involve direct flames, such as furnaces, kilns, fireplaces, chimneys, barbecues, and pizza ovens.