English bond:
English bond has two
alternating courses of stretchers and headers
Rat
trap bond:
Rat-trap bond
also known as Chinese bond
is a type of garden wall bond similar to Flemish bond but consisting of
rowlocks and shiners instead of headers and stretchers (the stretchers and
headers are laid on their sides, with the bed face of the stretcher facing
outward). This gives a wall with an internal cavity bridged by the headers;
hence the name. The main advantage of this bond is economy in use of bricks,
giving a wall of one-brick thickness with fewer bricks than a solid bond. No
plastering of the outside face is required and the wall usually is quite
aesthetically pleasing and the air gaps created within the wall help make the
house thermally comfortable. In summer the temperature inside the house is
usually at least 5 degrees lower than the outside ambient temperature and vice
versa in winter.
Advantages:
·
Strength
is equal to standard 10" (250mm) brick wall.
·
The
air medium or cavity created in between the bricklayers helps in maintaining a
good thermal comfort inside the building.
·
As
the construction is done by aligning the bricks from both sides with the plain
surfaces facing outwards, plastering is not necessary except in a few places.
·
Buildings
up to two stories can easily be constructed with this technique.
·
In R.C.C.
framed structures, the filler walls can be made of rat-trap bond.
Material:
·
Conventional
English bond (9’’thk wall) 350 bricks are required per cu. m whereas in
Rat-trap bond only 280 bricks are required and also the reduced number of
joints reduces the mortar consumption.
Cost
saving:
·
In the Rat Trap
Bond bricks are placed on edge in 1:6 cement mortar. With this technique there
is reduction in cost of the wall by 25%,
(reference- HUDCO)
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