Burnt Clay, Concrete, Sun-Dried, and More
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Updated on 06/22/23
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In This Article
In the history of professional construction practices, brick is one of the oldest materials for homes and building projects. It is also arguably the most durable since all types of brick walls, foundations, pillars, and road surfaces are still intact from thousands of years ago.
Burnt clay bricks are the classic red brick style found on many homes and buildings, but bricks can be made of many different materials for various purposes. The types of bricks are categorized according to their component materials and method of manufacture.
Here, learn about the seven most common types of brick that are best for construction and home renovation.
What Is Brick?
Officially, the term "brick" is used to denote a building unit made of shaped clay, but in modern times it refers to any stone- or clay-based building unit that is joined with cementitious mortar when used in construction.
Typically, brick sizes are about 8 inches long and 4 inches wide, coming in various thicknesses. Sizes also vary by country. Standard brick prices vary widely from $.25 to $4 per brick. Larger stone- or clay-based building units, such as those used in foundations, are called "blocks."
Types of Bricks
In modern construction practices, bricks are categorized according to their component materials and method of manufacture. Under this classification, here are seven common types.
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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.
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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.
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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.
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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
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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.
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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
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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.
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Benefits of Using Bricks
There are many advantages when bricks are used in construction.
- Aesthetic: Bricks offer a variety of natural colors and textures.
- Strength: Bricks offer high compressive strength.
- Porosity: The ability to release and absorb moisture helps regulate temperatures and humidity inside structures.
- Fire protection: When appropriately prepared, brick can resist fire at maximum protection ratings for up to eight hours.
- Sound attenuation: The amount of sound a brick wall blocks out varies, but standard forms can block an average of 60-70 decibels, and brick walls can be constructed to block over 200 decibels.
- Insulation: Bricks absorb and release heat slowly for excellent thermal insulation compared to other materials. By helping to regulate and maintain the constant interior temperatures of a structure, bricks can save 50 percent more energy than wood.
- Wear resistance: Strong composition resists wear and tear common in other materials.
Tip
Unlike wood, bricks are man-made, requiring no excavation, deforestation, or exploitation of non-renewable resources.
How Bricks Are Made
Bricks are made in various ways, often from a clay-based material, molded into shape, and then fixed in form with heat or other drying processes.
The oldest bricks used natural clay and were dried in the sun. Sun-dried bricks may be the oldest type but also the weakest. Over time, techniques were developed to make bricks stronger and more resilient to weight, heat, weather, and erosion.
The composition of bricks can be changed to achieve desired qualities by mixing clay with concrete, ash, or various chemicals for different purposes. For example, fire bricks contain silica and alumina so they can remain extremely durable when exposed to direct flames.
How Bricks Are Categorized
Brick can be categorized in several ways. For example, you can divide brick in the following three ways:
- By facing: Facing (exposed) vs. backing (structural and hidden from view)
- By manufacturing method: Unfired (air-cured) vs. fired (oven-baked)
- By use: Common bricks (used for residential construction) vs. engineering bricks (used in heftier civil projects)
Tip
Bricks can be categorized according to different features, but categories overlap, and the taxonomy—though very descriptive—is imperfect.
Bricks can also be categorized according to their shape:
- Brick veneers are thin and used for surface cladding.
- Airbricks contain large holes to circulate air and decrease weight for suspended floors and cavity walls.
- Perforated bricks have many drilled cylindrical holes and are very light in weight.
- Bullnose bricks are molded with round angles.
- Paving bricks contain iron for underfoot paving applications.
- Capping bricks top freestanding walls.
- Hollow bricks are about one-third of standard bricks' weight for non-load-bearing partition walls.
FAQ
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What kind of brick is used for houses?
Both burnt clay brick (fired) and unburnt clay brick (cured without heat) are robust forms of brick used for house construction. Burnt clay is more commonly used for home construction though unburnt clay is slowly becoming more popular as a greener option that uses less energy to manufacture.
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What is the strongest brick?
The strongest bricks are known as Class A engineering bricks. Class A bricks are not used for their aesthetics and are rarely used for facing bricks. They are used for their compressive strength and low water absorption rates. The bricks are typically used for commercial applications, such as underground structures that may be affected by water and frost.
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What is the cheapest type of brick?
Machine-made bricks are the cheapest bricks, costing much less than hand-made or hand-molded bricks. In addition, it is common for builders and developers to use bricks laid in a stretcher bond, also called a running bond (laid lengthwise) because it reduces the amount of bricks needed as well as the labor and time necessary to lay the bricks.
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Efflorescence: Causes and Prevention. The Brick Industry Association.
The Many Types of Bricks. The American Ceramic Society.
Zhen-Dong Cui et al. Design of Underground Structures. Springer, 2019.
Sustainable Building Materials. African Sustainability Academy.
Do I need Fire bricks for a fireplace or braai? The Clay Brick Association of Southern Africa.
Technical Notes on Brick Construction. The Brick Industry Association.
Özge Andiç-Çakır et al. Improvement of traditional clay bricks’ thermal insulation characteristics by using waste materials. Case Studies in Construction Materials, vol. 15, 2021. doi:10.1016/j.cscm.2021.e00560
Fire Resistance of Brick Masonry. The Brick Industry Association.
Unfired clay bricks. Greenspec.
