What Is Rat Trap Bond:
Rat trap bond is a type of brick masonry wall in which bricks are laid in vertical position instead of conventional horizontal position creating a hollow space (cavity) within the wall. It is also known as Chinese brick bond.
Method Of Construction:
The rat trap bond construction is a modular type of masonry construction. In this type of brick, masonry bricks are placed on edges making visible the shinner and rowlock. Thus 110 mm face is exposed from front elevation (for brick size of 230mmx110mmx75mm). This gives the wall an internal cavity which provides effective thermal insulation.
Advantages Of Rat Trap Bond:
The advantages of rat trap brick masonry are as following:
1. It requires approximately 30% less bricks and 50% less mortar than conventional masonry. Reduces the cost of a 9″ wall by 20-30%.
2. Strength is equal to a standard solid brick wall.
3. Cavity induced in wall provides advantage of thermal comfort. Makes the interior cooler in summer and warmer in winter.
4. It can be used as thick partition wall as well as load-bearing wall.
5. It reduced material requirement results in considerable cost saving.
6. All pillars, lintels, sill bonds, electrical conducts, tie beams etc can be concealed. Better aesthetic looks for exposed brickwork.
7. For more structural safety, reinforcement bars can be inserted through the cavity until the foundation.
Disadvantages Of Rat Trap Bonds:
The disadvantages of rat trap brick masonry are as following:
1. It does not provide good sound insulation.
2. Extra care must be taken while designing the wall length and heights for a structure.
3. It requires trained masons, otherwise wastage of mortar falling into the cavity.
4. On average a rat trap brick wall needs cleanness of external surface (if not plastered) every three years.
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