What Is Rat Trap Bond? | Construction of Rat Trap Bond | Advantages & Disadvantages of Rat Trap Bond in Masonry Work

Introduction of Rat Trap Bond?

There are different types of bonds for brick masonry walls in construction.  Brick masonry is usually made by filling mortar into brick layers and grooves according to the bond.

Brickwork is done according to a pattern or structure in construction. Or in other words, a brick wall can also be defined as the arrangement of bricks in different patterns in construction, which is commonly called a brick bond.

Each of the brick bonds has its own look and structural considerations in the special case of the walls.

The strength of brick masonry in construction depends on the type of bond and material of the brick, which helps to give brick masonry proper stability, strength, and durability.

The first concept of rat trap bond as a bond for brickwork was introduced in 1970 by architect Mr.Laurie Baker in Kerala.

The various benefits of using a rat trap bond include fire resistance and aesthetic properties. So rat trap bonds are emerging very fast in the construction sector.

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What Is Rat Trap Bond?

Rat trap bond is a technique used for wall construction. Rat trap Bond is a type of masonry bond.

In this Rat trap bond, the bricks are laid in a vertical position. Thus there is a cavity between the walls. In this type of bond, the wall thickness can be kept the same as a traditional brick masonry wall. The formation of rat trap Bond is known as Chinese brick bond.

Using this rat trap Bond of masonry bond can reduce the number of bricks and mortar compared to English / Flemish bonds. This reduction is due to cavities formed in the wall.

The bond was created by architect Mr.Laurie Baker. This type of brick bond does not reduce the strength of the wall. Therefore, the use of rat trap bonds makes it possible to use the material as required, which can be used for construction cost and better thermal efficiency than traditional masonry.

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Material Selection for Rat Trap Bond in Masonary Work

Brick

• The choice of bricks is extremely important in construction for this type of rat trap bond. Because in the masonary work done by this rat trap bond method, there is a cavity between the two bricks.
• The size of the bricks for this method requires a standard size. So in this type of masonary work, the difference in the size of the brick is not accepted.
• The bricks used for the rat trap bond should have straight edges and right angles. In addition, the brick should be full rectangular size.
• The masonry done by this method is of modular type. So the brick must be the same size to achieve good strength and finish of masonary wall.

Mortar

• Mortar plays an important role in strengthening masonary wall for the rat trap bond method.
• The rat trap bond method usually uses a 1: 4 mortar.

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Construction of Rat Trap Bond

The rat trap bond is done by following the steps for the construction of the masonry wall,

• The bricks are laid vertically on the mortar. Fixing is done by 90 mm side surface of the brick. The standard size of brick in elevation is 190 mm * 90 mm * 90 mm.
• So that the inside of the wall forms a cavity between two bricks with a length of 190 mm.
• In lintels, seals, and other openings by rat trap bond, cavities are not formed for fixing the frame.
• To give strength and stability to the lintel and frame, a reinforcement bar can be provided.
• If through proper designing and planning, electrical wires and fittings can be concealed through internal cavities.

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Advantages & Disadvantages of Rat Trap Bond in Masonry Work

Advantage of Rat Trap Bond in Masonry Work

Below are some of the benefits of rat trap bond masonry work.

1. Advantage of Rat Trap Bond: Appearance

Proper finishing masonry wall made by this type of rat trap bond in construction gives the outside surface of the wall an attractive appearance.

The plastering process can be avoided in proper masonry work done by rat trap Bond.

2. Advantage of Rat Trap Bond: Thermal insulation

The main advantage of rat trap bonds is thermal insulation, which is effective in reducing the room temperature from the outside temperature. This can reduce the cost of electricity.

The masonry work done by rat trap Bond helps maintain temperature against both heat and cold in all weather conditions.

3. Advantage of Rat Trap Bond: Load bearing capacity

The use of rat-trap bonds in masonry work does not affect the load-bearing capacity. It has the same load-bearing capacity as other masonry brick bonds.

This method of the rat-trap bond can be used in brickwork to reduce construction materials.

4. Advantage of Rat Trap Bond: Cost saving: Reduce Dead load

The use of rat trap bond in masonry construction is 20% less dead load than other traditional masonry work, which reduces the total load on the base.

5. Advantage of Rat Trap Bond: Cost saving

Using a method like rat-trap bond can save about 30% bricks and 50% mortar compared to conventional masonry.

Doing this type of rat trap bond in masonry reduces the total material consumption, which is beneficial for total costing in the construction budget.

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Disadvantage of Rat Trap Bond in masonry work

1. The rat trap bond method for masonry work is used by skilled workers. If skilled labor is not familiar with this method, pre-training is required, which may increase the cost of labor.
2. The masonry work done by the rat-trap bond is not able to resist the noise. Therefore, the use of this method should be avoided for a soundproof wall.
3. Bricklaying in this type of method should be done properly in line and level. Therefore special care should be taken for masonry work done by this type of method.
4. The masonry work done by the rat trap bond needs to be maintained periodically.

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Important Point When Using the Rat Trap Bond Method

• For this type of method, the proper quality of the bricks is checked before using the bricks in the masonry work. In which the quality and sharp edges of the bricks are checked for masonry work.
• The surface layer or the first layer should be solid before using this type of method in masonry work.
• The sides should be solid in exposed areas such as seals and lintel layers. Therefore it is necessary to do solid masonry work in this type of rat trap bond next to the framework for doors and windows.
• If more strength is required in the construction of the building, extra reinforcement can be done in the cavity of the rat-trap bond. In addition, reinforcement can be placed to resist natural effects such as earthquakes.
• Electrical appliances and plumbing pipes can be concealed through proper planning and smart work.
• Particular care is taken for masonry work done by rat trap bond than the construction of traditional 9-inch brickwork. Such as line, level.
• According to the experiment or survey, the old method used 350 bricks in one m3. While rat trap bond requires 250 bricks. Thus this method reduces the consumption of brick and mortar, which affects the building budget.

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