Bricks

There are several kinds of bricks, but we can say that most of them are made out of clay that is a group of superficial minerals that arise from the weathering of igneous rocks.
 * What are they made of?

Bricks have been used in the construction of buildings and roads for hundreds of years There are for types of bricks:
 * What are they used for?
 * How many types of brick are there?
 * 1) Mud bricks: The soft mud method is the most common, as it is the most economical. It starts with the raw clay, preferably in a mix with 25-30% sand to reduce shrinkage. The clay is first ground and mixed with water to the desired consistency. The clay is then pressed into steel moulds with a hydraulic press. The shaped clay is then fired ("burned") at 900-1000 °C to achieve strength.
 * 2) Dry pressed bricks: The dry press method is similar to mud brick but starts with a much thicker clay mix, so it forms more accurate, sharper-edged bricks. The greater force in pressing and the longer burn make this method more expensive.
 * 3) Extruded bricks: Most structural bricks are made by this method, as hard dense bricks result, and holes or other perforations can be produced by a die. The introduction of holes reduces the needed volume of clay through the whole process, with the consequent reduction in cost. The bricks are lighter and easier to handle, and have thermal properties different from solid bricks.
 * 4) Calcium silicate bricks: The raw materials for calcium silicate bricks include lime mixed with quartz, crushed flint or crushed siliceous rocktogether with mineral colourants. The finished bricks are very accurate and uniform, although the sharp arrises need careful handling to avoid damage to brick (and brick-layer). The bricks can be made in a variety of colours, white is common but pastel shades can be achieved.

Brick laying techniques are the ways to bond the bricks together into a single structural unit.
 * What is the meaning of //brick laying techniques//?

__Stretcher bond__ is the simplest repeating pattern but it is only suitable for a wall half a brick thick, the thinnest possible wall. Such a thin wall is not stable enough to stand alone, and must be tied to a supporting structure. It is common in modern buildings, particularly as the outer face of a cavity wall or as the facing to a timber framed structure. __Flemish bond__ is created by alternately laying headers and stretchers in a single course. The next course is laid so that a header lies in the middle of the stretcher in the course below.
 * Describe 2 brick laying techniques

The advantages of using bricks are many, starting with its aesthetic looks and its huge weight resistance. It only present issues when it comes to vertical stability, but people have figured out the way to deal with this along the history. We can say that if it is well employed, brick is certainly one of the best constructions material.
 * What are their advantages and disadvantages?