Glazed Bricks: Features & Properties

Reading time: 1 minute

Glazed bricks are extruded clay masonry units with ceramic coating fused on their exterior surface. These bricks being both attractive and durable find their use in exterior as well as interior construction.

Glazed brick units are used mainly for wall applications like structural walls, partition walls, multi-wythe walls, or veneers. 

This article discusses the features and advantages of glazed bricks used in the construction industry. 

Features of Glazed Bricks

1. Glazed bricks are fired twice during their production in kilns. Initially, they are fired as a part of the making process and secondly for fusing the ceramic coating with the brick’s surface.
2. The ceramic finish provided for bricks are available in many standard and custom colors. 
3. The surface of glazed brick forms an impervious layer that is highly tolerant against impact and abrasion.
4. They are resilient to staining and graffiti, water, and frost damage, ensuring to retain their integrity for generations.
5. The code ASTM C 126-99: Standard Specification for Ceramic Glazed Structural Clay Facing Tile, Facing Brick, and Solid Masonry Units gives the details of ceramic glazed bricks used for walls.
6. The ceramic glaze is fused to the body of the brick at a temperature above 1500^oF, making them an inseparable layer.
7. The different grades and types of glazed bricks as per ASTM standards are given in Table-1 below:

Grade S (Select)	Used where the mortar joints are narrow
Grade SS (Select sized or ground edge)	Used where the variation of face dimension is small
Type I (Single-faced units)	Used where only one finished face is exposed
Type II ( Two-faced units)	Used where two opposite finished faces are exposed

8. ASTM C 126 and C 1405 provide specifications for glazed bricks and the properties of ceramic glaze used for the manufacturing. The major properties of glaze material covered in the code are imperviousness, opacity, resistance to fading, resistance to crazing, flame spread, fuel contribution and smoke density, toxic fumes, hardness, and abrasion resistance. 
9. Glazed masonry units can be used for load-bearing and non-loadbearing wall applications.
10. The ceramic glazed bricks are heavy due to the extra coat and are able to withstand most harsh weather conditions. It has been used repeatedly in regions with below-freezing temperatures and even in warmer regions.
11. The weights of glazed bricks vary based on the raw material, size, manufacturing process, and amount of corning. The average weight of glazed brick that meets the requirements of ASTM C 1405 is given in Table-2 below:

Considerations in Glazed Brick Masonry Construction

The durability of glazed brick is dependent on effective water management. As per Brick Industry Association (BIA), glazed bricks must not be used in areas that are likely to get saturated. When used in water-saturated areas, a drainage system that allows the water entering the wall system to drain away must be designed. 

The glazed surface may not let the water penetrate, but the mortar joints, when prone to frequent water and moisture, have chances to deteriorate. Therefore, along with the construction of the exterior glazed brick wall, a vented drainage type wall system must be installed to properly collect water coming inside the wall cross-section.

Glazed bricks are heavier compared to standard bricks. Hence, the foundation design must consider this extra weight of glazed bricks.

Advantages of Glazed Bricks

1. Glazed bricks are highly versatile. They are available in various shapes, sizes, colors, and finishes.
2. Glazed bricks can be cleaned using simple soap water. Hence, it demands minimal maintenance.
3. As glazed bricks are made out of burned clay and with fused ceramic, they possess high resistance to fire.
4. The ceramic layer on bricks enhances the brick resilience and endurance. Hence, they are highly durable.
5. Glazed bricks can be colored or shaded to match with the aesthetics of the surrounding area. 

However, the production of glazed bricks demands a high temperature and requires two-time firing. This consumes a lot of energy. In addition to this, the glaze material used for the fusing is very costly, making glazed bricks an expensive product. 

FAQs

Read More

Difference Between AAC Blocks and Clay Bricks

Acid-Resistant Bricks: Properties, Types, Tests, and Advantages