Category Archives: bricks

Types of bonds in brick masonry walls – Advantages and features

Types of bonds in brick masonry commonly used in construction are detailed in this article. The process of bonding bricks with mortar in between them is known as brick masonry. Bricks are arranged in a pattern to maintain their aesthetic appearance and strength. This article is about the various types of bonds in brick masonry walls.

Bricks are rectangular construction materials. Bricks are commonly used in the construction of walls, paving, and other structures. They are also inexpensive and simple to work with.

  1. Types of Brick masonry bonds – Features
  2. Types of Bonds in brick masonry
    1. Stretcher bond – Types of Bonds in brick masonry
      1. Limitations of Stretcher bonds
      2. Applications of stretcher bonds
    2. Header bond – Type of Bonds in brick masonry
    3. English Bond – Types of bonds in brick masonry
    4. Flemish Bond
    5. Double flemish bond
    6. Single Flemish Bond
    7. Raking bond
    8. Zigzag Bond
    9. Facing Brick Bonds
    10. Dutch Bond
    11. Rat trap bond

Types of Brick masonry bonds – Features

For all types of brick masonry bonds to be stable and of high quality, the following characteristics must be followed.

  • Bricks should be uniform in size.
  • The lap should be a minimum of 1/4 brick along the length of the wall and 1/2 brick across the thickness of the wall.
  • Uniform lapping is to be maintained.
  • Avoid using too many brickbats.
  • For getting a uniform lap Length of the brick should be twice its width plus one joint.
  • The centre line of the header and stretcher in the alternate courses should coincide with each other for the stable wall.
  • Stretchers should be used in facing and a header should be used in hearing.

Types of Bonds in brick masonry

There are different types of brick masonry bonds. They are

  • Stretcher Bond
  • Header Bond
  • English Bond
  • Flemish Bond
  • Raking bond
  • Zigzag Bond
  • Herring-Bone Bond
  • Facing Bond
  • Dutch Bond
  • Diagonal Bond
  • Rattrap bond

Let us have a look at the most commonly used types of bonds in brick masonry.

Stretcher bond – Types of Bonds in brick masonry

The stretcher is the brick’s lengthwise face or otherwise known as the brick’s longer, narrower face, as shown in the elevation below. Bricks are laid so that only their stretchers are visible, and they overlap halfway with the courses of bricks above and below. Accordingly, In this type of brick bond, we lay the bricks parallel to the longitudinal direction of the wall. In other words, bricks are laid as stretchers in this manner. It is also referred to as a walking bond or a running bond. Additionally, it is among the simplest and easiest brick bonds.

Stretcher Bond - Types of bonds in brick masonry

Limitations of Stretcher bonds

  • Stretcher bonds with adjacent bricks, but they cannot be used to effectively bond with them in full-width thick brick walls.
  • They are only suitable for one-half brick-thick walls, such as the construction of a half-brick-thick partition wall.
  • Stretcher bond walls are not stable enough to stand alone over longer spans and heights.
  • Stretcher bonds require supporting structures such as brick masonry columns at regular intervals.

Applications of stretcher bonds

Stretcher bonds are commonly used as the outer facing in steel or reinforced concrete-framed structures. These are also used as the outer facing of cavity walls. Other common applications for such walls include boundary walls and garden walls

Header bond – Type of Bonds in brick masonry

Generally for header bond, the header is the brick’s widthwise face. In brick masonry, a header bond is a type of bond in which bricks are laid as headers on the faces. It’s also referred to as the Heading bond. The header is the brick’s shorter square face, measuring 9cm x 9cm. As a result, no skilled labour is required for the header bond’s construction. While stretcher bond is used for half brick thickness walls, header bond is used for full brick thickness walls that measure 18cm. Generally, in the case of header bonds, the overlap is kept equal to half the width of the brick. To achieve this, three-quarter brickbats are used in alternate courses as quoins.

header bond - Types of bonds in brick masonry
header bond

English Bond – Types of bonds in brick masonry

English bond uses alternative courses of stretcher and headers and is the most commonly used and the strongest bond in brick masonry. However, a quoin closer is used at the beginning and end of a wall after the first header to break the continuity of vertical joints. Mostly, a quoin close is a brick that has been cut lengthwise into two halves and is used at corners in brick walls. Similarly, each alternate header is centrally supported over a stretcher.

Types of bonds in brick masonry - English bond

Flemish Bond

In Flemish bond, each course is a combination of header and stretcher. Accordingly, the header is supported centrally over the stretcher below it. Generally,closers are placed in alternate courses next to the quoin header to break vertical joints in successive layers. Flemish bond, also known as Dutch bond, is made by laying alternate headers and stretchers in a single course. The thickness of Flemish bond is minimum one full brick.The drawback of using Flemish bond is that it requires more skill to properly lay because all vertical mortar joints must be aligned vertically for best results. Closers are placed in alternate courses next to the quoin header to break vertical joints in successive There are two types of Flemish bond

  • Double Flemish bond
  • Single Flemish bond

Double flemish bond

The double flemish bond has the same appearance on both the front and back faces. As a result, this feature gives a better appearance than the English bond for all wall thicknesses.

Single Flemish Bond

The English bond serves as the backing for a single flemish bond, which also includes a double flemish bond on its facing. As a result, both the English and Flemish bonds’ strengths are utilised by the bond. Similarly ,this bond can be used to build walls up to one and a half brick thick. Howerver,high-quality, expensive bricks are used for the double-flemish bond facing. Cheap bricks in turn may be used for backing and hearting.

The appearance of the Flemish bond is good compared to the English bond.  Hencer, flemish bond can be used for a more aesthetically pleasing appearance. However, If the walls must be plastered, English bond is the best choice.

Flemish bond

Raking bond

Raking bond is a type of brick bond in which the bricks are laid at angles. In this case, bricks are placed at an inclination to the direction of walls. Generally, it is commonly applicable for thick walls. Normally laid between two stretcher courses. There are two types of Raking bonds

raking bond
  • Diagonal bonds
  • Herringbone bonds

Diagonal bonds

In diagonal bonds, bricks are laid inclined, the angle of inclination should be in such a way that there is a minimum breaking of bricks. These dioganal bonds are mostly applicable for walls of two to four brick thickness. Similarly, the triangular-shaped bricks are used at the corners. 

Herringbone bonds

This type of bond is applicable in thick walls. The bricks are laid at an angle of 45 degrees from the centre in two directions. Mostly used in paving. 

Zigzag Bond

In this type of bond, bricks are laid in a zig-zag manner. It is similar to the herringbone bond. Since Zig zag bond has an aesthetic appearance it is used in ornamental panels in brick flooring. 

zig zag bond
zig zag bond

Facing Brick Bonds

In facing bond bricks are used of different thicknesses. It has an alternative course of stretcher and header. The load distribution is not uniform in this type of bonding. So it is not suitable for the construction of masonry walls.

facing bond
facing bond

Dutch Bond

It is a type of English bond. The specific pattern of laying bricks for building a wall is known as English and Dutch bonds. The primary distinction is that English Bond is a bond used in brickwork that consists of alternate courses of stretchers and headers. Dutch bond – made by alternating headers and stretchers in a single course.

Rat trap bond

rat trap bond
rat trap bond

Another name of the rat trap bond is the Chinese bond. In this type of bond, the bricks are placed in such a way that a void is formed between them. These voids act as thermal insulators. Thus provides good thermal efficiency. It also reduces the number of bricks and the amount of mortar. Construction of rat trap bonds requires skilled labours.

Refractory Bricks – Properties and Types

Refractory bricks, also known as firebrick are ceramic materials used to line furnaces, kilns, fireboxes, and fireplaces. A refractory brick is designed to withstand high temperatures while still having poor thermal conductivity for increased energy efficiency. Refractory bricks are used in place of regular bricks, which always have a tendency to shatter at high temperatures. These bricks may also go by the titles ceramic bricks or fire bricks. Brick is one of the most popular construction materials used since ancient times. Regular bricks tend to crack at high temperatures and are not preferred for high-temperature areas. In such conditions, conventional bricks are often replaced by Refractory bricks.

This article is about refractory brick, their types, and their properties.

  1. What are refractory bricks?
  2. Properties of Refractory brick
  3. Types of Refractory bricks
    1. Acid refractory bricks
    2. Basic refractory bricks
    3. Neutral refractory bricks

What are refractory bricks?

Refractory brick is a type of brick that can resist high temperatures. It is also known as ceramic bricks or fire bricks. Generally, they are yellowish-white in colour. These bricks have good thermal resistance and good compressive strength. The chemical composition of fire bricks differs from regular bricks’ chemical composition. It mainly consists of 25 to 30% alumina, and 60 to 70% silica. Also, oxides of magnesium, calcium, potassium etc are present. The main application of fire bricks is in the construction of kilns, furnaces, etc. They are able to withstand temperatures above 2100 degrees Celsius. Thus the thermal capacity helps the structure to be stable at high temperatures. 


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Properties of Refractory brick

Following are the properties of Refractory brick.

  • Refractory brick should resist high temperatures.
  • They have good compressive strength. 
  • The weight of fire bricks is 150 lbs per cubic ft. 
  • The size of refractory brick is 9×4.5×2.5 inches or 9×2.7×2.25 inches. 
  • They also have good chemical resistance, Since they do not react with the furnace gases. 
  • The water absorption of refractory brick is 5 to 10%. 
  • They have a high fusion point. 

Types of Refractory bricks

Refractory bricks are available in various sizes and shapes. There mainly three types of refractory brick

  • Acid refractory bricks
  • Basic refractory Bricks
  • Neutral refractory Bricks

Acid refractory bricks

The acid refractory brick includes silica bricks and ganister bricks. Silica brick consists of 93% of Silicon dioxide. They possess good strength and fusion points. Also, they are hard and it is suitable for acid lining in furnaces. They can withstand temperatures up to 2000 degrees Celsius. Silica bricks are made from sandstone or quartzite. Ganister bricks consist of 85% of silica, 10% clay and 2% of lime. They are also hard and can withstand temperatures up to 2100 degrees Celsius. But acid bricks are not suitable to undergo rapid temperature. Since they tend to spall. 

Basic refractory bricks

Basic refractory bricks are basic in nature. They have good corrosion resistance and chemical resistance. They consist of Magnesite bricks, dolomite bricks and Bauxite bricks. Magnesite bricks contain 85% of magnesium oxide and 3 to 5% of iron oxide. They are suitable for the lining of the furnace. They can withstand temperatures up to 1800 to 2100 degrees Celsius. Dolomite bricks can withstand temperatures up to 1400 to 1600 degrees Celsius. It contains a high amount of dolomite. Bauxite bricks are a type of basic refractories that can withstand temperatures up to 1600 degrees Celsius and contains 85% of bauxite. 

Neutral refractory bricks

Neutral refractory bricks are suitable in places to separate the acid and basic lining in the furnace. They consist of chromite bricks, carborundum, spinal bricks and forsterite bricks. These bricks have a high percentage of chrome and magnesite. 

Testing of Bricks – Top 8 Test on bricks to ensure quality

Testing of Bricks is performed both on the job site and in the laboratory. A variety of test on bricks is performed to verify their suitability for use in construction. Bricks are one of the oldest and most significant building materials due to their longevity, dependability, strength, and low cost. Bricks are construction materials made of clay and come in a specific size. Additionally, they are the foundational components of construction. Brick is a building material that has been around for a long time. They serve as both a load-bearing structure and a load-transfer medium. The dimensions of the brick are 190 mm × 90 mm × 90 mm. They have sharp edges and are also rectangular.

Audio on test on bricks
Audio on test on bricks
  1. Requirement of Good Quality Bricks and Significance of test for bricks
  2. Testing of Bricks – Top 8 tests on bricks
    1. Water absorption testing of bricks
  3. Compressive strength of brick/Crushing strength of brick
  4. Efflorescence test on brick – Testing of bricks
  5. Hardness test on bricks
  6. Shape and size Testing of Bricks
  7. Colour test of bricks
  8. Structure Test on Bricks
  9. Soundness test of bricks

Requirement of Good Quality Bricks and Significance of test for bricks

The following are the fundamental requirements for a good quality brick, making testing of bricks and brick quality checks essential.

  • Bricks should be homogenous and compact.
  • They should have equal proportions of clay, sand, and silt. 
  • Bricks should have requisite plasticity.
  • They should be free from defects like lumps and holes. 
  • The shape of the brick should be rectangular. 
  • A good brick should not break if dropped from a one-meter height.
  • Brick should not possess internal cracking and shrinkage.
  • The brick should be fire and scratch-resistant.
  • Water absorption of brick should not exceed 20 per cent of its dry weight. 
  • The compressive strength of the brick should not be less than 3.5N/mm2.
Good quality bricks
Good quality bricks

To maintain these qualities, testing of bricks should be done. This article discusses the test on bricks that are carried out to ensure the quality of good bricks.

Testing of Bricks – Top 8 tests on bricks

In order to find the quality and sustainability of the bricks, various tests on bricks are performed. Further in this article, we have listed the top 8 tests on bricks.

  • Water absorption test of brick
  • Compressive strength test of brick/ crushing strength test on bricks
  • Hardness test of brick
  • Shape and size test of bricks
  • Colour test of bricks
  • Soundness test of brick
  • Structure of brick test
  • Efflorescence test of brick

Water absorption testing of bricks

A water absorption test of the brick is performed to determine the amount of moisture absorbed by the brick under extreme conditions. The purpose of the water absorption test of bricks is to determine their durability of the bricks. The water absorption test necessitates the use of a weighing machine and a drying oven.

  • Firstly, the brick specimen is dried in a drying oven 
  • After that, weigh the dry specimen using the weighing machine and mark it as W1.
  • Secondly, immerse the brick in water for 24 hours.
  • Then take the brick out and drain the water.
  • Similarly, measure the weight and mark it as W2.
  • Finally using the formula determine the water absorption.

Water absorption = (W1 -W2) / W1 x 100

The moisture content of the brick is thus determined by the difference between the dry weight and the wet weight. Water absorption for high-quality bricks should be less than 20% of the dry weight. This brick test ensures that the brick is long-lasting and can withstand extreme weather conditions.

Compressive strength of brick/Crushing strength of brick

The ability of the brick to withstand a particular load without failure is the compressive strength of the brick.

A compressive strength testing machine is the apparatus for determining the compressive strength of brick.

  • First, Take three sample specimens and submerge them in water. 
  • After 24 hours, drain the water. Fill the frog and void with mortar in a ratio of 1: 3. 
  • Subsequently, store the brick in jute bags for 3 days. 
  • Place the brick in the compression testing machine with the brick frog area facing upwards. After that apply the load slowly.
  • Note down the load at which the bricks break.
  • Finally, using the formula to determine the compressive strength of brick. 

Compressive strength (N/mm2) = Maximum load at bricks fail/ Loaded area of brick

For good quality bricks, the compressive strength should not be less than 3.5 N/mm2

Compressive strength of brick/Crushing strength of brick - Apparatus
Compressive strength of brick/Crushing strength of brick – Apparatus

Efflorescence test on brick – Testing of bricks

A good quality brick should be free of soluble salts. However, If soluble salts are present, they form a white substance on the brick surface. Generally, efflorescence on brick is the name given to this white formation. The test procedure for performing the Efflorescence test on brick is as follows.

  • First, take a brick specimen and submerge it in water for 24 hours. 
  • After 24 hours, drain the brick and allow them to dry.
  • Keenly observe the brick surface.
Brick surface conditionDegree of Efflorescence
No white substanceZero efflorescence
10% white substanceSlight efflorescence
50% white substanceModerate efflorescence
More than 50% white substanceHeavy efflorescence
Efflorescence test on brick – Range
Efflorescence Test on Bricks
Efflorescence Test on Bricks

Hardness test on bricks

The hardness test on bricks is a field verification test. Hence they are performed on-site. A good brick should resist scratches against sharp things. The following is the test procedure for the hardness test on bricks.

  • At first, choose a brick randomly from the stack.
  • Using a nail or finger make a mark on its surface. 
  • If there is no scratch, then it is a good quality brick.

Shape and size Testing of Bricks

A good quality brick should be uniform in size and rectangular in shape. In order to check this, measure the brick on the field. The standard size of the brick is 190mm x 90mm x 90mm.

  • Randomly, choose 20 bricks from the stack.
  • Sort them in length, width and height wise.
  • If the sizes are the same, Then they are good bricks.
shape and size test of bricks
shape and size test of bricks

Colour test of bricks

Normally good quality bricks are deep red or copper colour. The colour test is a field test. Therefore, it can be observed visually.

Structure Test on Bricks

Homogeneity and compact structure are the quality of good bricks. 

  • Randomly, pick one brick from the stack.
  • Cut the brick into two pieces at the centre. 
  • Then observe its inner side.
  • They should be free from defects such as lumps, holes etc. 

Soundness test of bricks

The soundness test of bricks is a field test used to determine the strength of the bricks.

  • In this test, choose two bricks randomly without damage or break.
  • Hit the bricks with each other. 
  • Then, listen to the sound the brick produce. 
  • If a metal ringing sound is produced, then it is good quality bricks.