Brick is the oldest and most useful construction material used all over the world for masonry construction. Brick masonry is used extensively as it is a highly durable form of masonry construction. In simple terms, brick masonry is constructed by placing several bricks on the mortar in a proper sequential manner to form a solid mass that is capable of resisting the imposed loads.
Bond in brick masonry is the feature that adheres the bricks laid in the mortar together. Such a phenomenon of arranging the bricks in the mortar in a systematic manner in masonry construction is known as brick bonding. On account of this, bonds in brick masonry are developed by filling the mortar between the layers of bricks and in grooves where the bricks are laid adjacently. There are 10 types of brick bonds that are explained below.
The major objectives of providing the bonds in brick masonry construction can be listed as follows:
a. To hold the building units together.
b. To resist all the imposed loads and external loads.
c. To ensure the strength and stability of the masonry structure.
d. To increase the aesthetic appearance of the masonry structure.
Rules for Bricklaying:
Following are the rules for bricklaying:
i) The brick to be used should be of uniform size. The length of the bricks should be twice the breadth of brick plus one mortar joints.
ii) The bricks should not absorb water more than 1/5 times or 20% of their weight when kept inside the water for 24 hours.
iii) The amount of lap should be minimum half brick across the thickness of the wall.
iv) The use of brickbats should be minimum.
v) Before use, the brick should be sucked in the water for at least 1 hour.
vi) The thickness of the mortar should not be more than 13 mm.
vii) The brick and mortar used in masonry should be as per the specification.
viii) Proper bonding should be adopted.
ix) The wall should be raised truly vertical and regular checking should be done by a plumb bob.
x) All the finished masonry walls should be cured for at least one week.
xi) If the large voids appear in masonry, they should not be fed only by the mortar.
xii) Wall masonry should not be raised more than one meter a day.
Types of Brick Bonds
Types of brick bonds that are most widely used include the following:
a. Stretcher Bond
Stretcher refers to the long face or part of the brick. Stretcher bond is constructed by laying the bricks in the mortar such that only the stretcher face of the bricks remain exposed.
Stretcher bond is also commonly referred to as the Running bond as it consists of a continuous running pattern. This type of bond is the simplest form of the bond used in brick masonry. It is most commonly used in the UK.
Stretcher bond is most commonly used as a facade for the main masonry structure and the construction of garden walls, boundary walls, division walls, chimney stacks etc. It can also be used as outer facing walls in reinforced concrete framed structures.
Advantages of Stretcher Bond
The major advantages of the stretcher bond in brick masonry can be listed as follows:
a. It is easy and simple to construct.
b. Skilled manpower is not required for the construction of stretcher bond.
Disadvantages of Stretcher Bond
Some of the disadvantages of the stretcher bond can be listed as follows:
a. Stretcher bond cannot be used in case of full-width thick brick walls as they are suitable only for half brick thick walls such as the partition walls.
b. When the structure has long span or height, the masonry walls cannot be constructed using the stretcher bond as it cannot withstand the loads imposed.
c. For landscaping and architectural masonry constructions, stretcher bond is not desirable.
b. Header Bond
As the name itself implies, header bond is formed by utilizing the header face of the brick. The header is the shorter square face of the brick as seen in the elevation.
Header bond is similar to the stretcher bond except that the header faces of the bricks are exposed. Also, unlike the stretcher bond, header bond is used for the walls with full brick thickness.
Header bond is also sometimes referred to as the heading bond. The arrangement of the bricks is done such that the overlap is equal to half the width of the brick. This is accomplished by using three-quarter brickbats as quoins i.e. the offsets are made by half a brick.
The header bond is desirable in case of curved brick masonry construction such as curved brick walls.
Advantages of Header Bond
Some of the advantages offered by the header bond can be listed as follows:
a. It is easy and simple to construct.
b. Skilled manpower is not required for the construction as in stretcher bond.
Disadvantages of Header Bond
Some of the disadvantages of header bond can be listed as follows:
a. It does not have considerable strength in the direction of the wall.
b. It is not desirable for the construction of aesthetically important masonry structures.
c. English Bond
English bond essentially consists of alternate header courses and stretcher courses of bricks. The overlap in English bond is formed by inserting a queen closer next to a quoin header. It is mostly used in Asian countries like India, Bangladesh, etc. It is more strong and durable as compared to header and stretcher bond.
Advantages of English Bond
Some of the advantages offered by the English bond can be listed as follows:
a. It offers great strength and stability.
b. It can be used for the construction of masonry walls of almost all thickness.
c. Highly skilled manpower is not required for the construction of such a bond.
Disadvantages of English Bond
Some of the disadvantages of English bond can be listed as follows:
a. It is not very aesthetically pleasing.
b. This type of bond construction is comparatively expensive.
c. There is a higher possibility of moisture ingress through the traverse joints.
d. Flemish Bond
Flemish bond is brick bond in which each course essentially consists of alternately placed headers and stretchers. The bond is thus developed by laying the header face and the stretcher face of the brick alternately in mortar such that every alternate course begins with a quoin header at the corner. To the next of quoin header, quoin closer is placed in alternate courses to develop face lap. In Flemish bond, the header face is centrally supported over the stretcher below it.
The Flemish bond can be further divided into the following types:
i. Single Flemish Bond:
The single flemish bond is the intermediate bond between the English bond and the Double Flemish bond. It consists of double flemish bond on the facing side and English bond on the backing face. Thus, single flemish bond gains adequate strength from the English bond whereas maintains the aesthetic appearance utilizing the Flemish bond.
ii. Double Flemish Bond:
The double Flemish bond consists of Flemish bond on both the backing side and the facing side of the masonry. It is highly appealing aesthetically and is thus used in architecturally important masonry structures.
Advantages of Flemish Bond
Some of the advantages of the Flemish bond can be listed as follows:
a. It is very economical.
b. It is highly appealing in terms of appearance.
Disadvantages of Flemish Bond
Some of the disadvantages of the Flemish bond can be listed as follows:
a. It requires highly skilled manpower for construction.
b. It is not as strong as the English bond.
e. Rat Trap Bond
Rat trap bond is also commonly referred to as the Chinese brick bond. It can be defined as the bond in which the bricks are laid edgewise i.e. the shiner and the rowlock face of the brick is visible on the facing side of the wall.
In other words, the rat trap bond is the masonry bond in which the bricks are laid vertically to form a cavity in the masonry wall. It is regarded as a form of modular masonry. It is constructed such that the masonry wall thickness is maintained the same as that of a typical or conventional masonry brick wall. The internal cavity thus formed is duly bridged by the rowlocks.
The rat trap bond is highly advantageous. This is because the cavity formed in the rat trap bond facilitates the reduction in the number of bricks and mortar required. The internal cavity formed also enhances the thermal insulation inside the building.
Advantages of Rat Trap Bond
Some of the advantages offered by a rat trap bond can be listed as follows:
a. It ensures the construction is highly cost-effective as the number of bricks required as well as the mortar required is reduced. In general practice, it has been found that a masonry wall constructed using other types of brick bond requires 500 numbers of bricks for 1m³ while the same masonry wall when constructed using the rat-trap bond requires only 430 numbers of bricks. This indicates that using rat trap bond for the masonry construction can reduce the number of brick required by 20% to 35% whereas the quantity of mortar required can be reduced by 30% to 50%.
b. It enhances the thermal regulation and comfort inside the masonry structure.
c. The internal cavity formed in the rat trap bond can also be utilized for the fitting of electrical wires, cables and sanitary pipes.
d. A well-constructed rat trap bond is aesthetically pleasing in appearance. It delivers a good finished look and thus there is no need for plastering and painting of the structure. This saves both the time of completion and the cost for plastering and painting works.
e. The internal cavity formed in the rat trap bond reduces the dead load on the structure thereby increasing the overall strength and stability of the structure as a whole. Such walls can be efficiently used both as the load-bearing structural walls and partition or dividing walls.
f. It offers a high degree of durability.
g. The maintenance needs as well as the cost is comparatively lower.
h. It also offers easy and efficient concealing of the tie beams, lintel beams, columns etc.
Disadvantages of Rat Trap Bond
Some of the disadvantages of a rat trap bond can be listed as follows:
a. Highly skilled and trained labour is required for the construction of a rat trap bond.
b. There may be a problem of sound insulation due to the internal cavity.
e. If proper technique and care are not taken, wastage of mortar may occur.
f. Zigzag Bond
zigzag bond is a bond in which the laying of the bricks is done in a zigzag manner. The zigzag bond is similar to the Herring-bone bond.
It offers a good aesthetic appearance and thus is mostly used for paving works in residential masonry constructions, floors, footpaths etc. However, the zigzag bond is non-load bearing in nature and cannot be used in the construction of main walls in masonry constructions.
g. Herring-Bone Bond
In herring-bone bond, bricks are laid at 45degree in both the directions from the centre in each course of the wall. It is similar to the zigzag bond. Such type of bond is highly desirable for the construction of very thick masonry wall i.e. for masonry walls equal to or greater than four bricks thick.
Herring-bone bond is most commonly used for the paving works. It can also be used for the construction of boundary walls as it can offer medium load-bearing strength.
h. Facing Bond
Facing bond is the type of brick bond in which the bricks are laid such that a header course comes only after several courses of stretcher course. It is mostly adopted for the construction of thick walls. Facing bond is highly desirable when the facing wall and the backing wall with different thickness have to be constructed. However, due to such variation in thickness, the number of joints in the facing and the backing face is not equal as a result the load distribution is not uniform. Such, non-uniformity may also lead to the unequal settlement of the masonry walls.
i. Dutch Bond
Dutch bond is simply a type of advanced or modified English bond i.e. Dutch bond consists of alternate courses of the headers and stretchers. The only modification in Dutch bond is that each stretcher course starts with a three-quarter bat and thus every alternate stretching course consists of a header placed next to the three-quarter bat which is provided at the quoin.
j. Diagonal Bond
Diagonal bond is the bond in which the bricks are placed in a diagonal manner i.e. the bricks are placed in an end to end fashion. Diagonal bond is desirable for the masonry walls that are two to four brick thick.
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