The use of fired ceramic bricks goes back more than three thousand years, and bricks
are still the preferred house construction material in most countries around the world. In
many countries, the brick industry is the largest single user of energy and also employs
a large number of workers, due to the labour intensive manual brickmaking process.
Suitable clays for manufacturing bricks exist almost everywhere, and the brick-making
process can be done with simple manual methods, or in highly automated plants,
depending on the prevailing labour cost and the demand of the market.
The Bull's trench kiln
The kiln can be made circular or elliptical in shape. It is constructed on dry land, by
digging a trench, 6 - 9 m wide, 2 - 2.5 m deep, and 100 - 150 m long. An alternative
method is to build up the sides of the kiln with bricks, especially where drainage is a
problem. Gaps are left in the outer wall for easy assess to the trench during setting and
drawing of bricks.
Fired bricks being drawn from the kiln (Pakistan)
A canvas prevents air from entering the kiln from the wrong end (Pakistan)
Types of Brick Bonds
Bonds are the horizontal patterns in which bricks are laid. There are five main types of
bonds used in old buildings.
Old English Bond
This is the oldest brick pattern. Bricks were laid in alternate layers of headers and
stretchers. A 'stretcher' is a brick laid so that its side is showing, a 'header' is a brick laid
so that only its end is showing.
To escape religious persecution, the Flemings settled in England during late Tudor
times. They introduced Flemish bond: headers and stretchers laid alternatively in each
layer of bricks.
Stretcher bond is the commonest bond used today and the least interesting to look at.
Properties of 3D