Masonry

STONES

Rubble masonry: In rubble masonry, the stones of irregular sizes are used.

Coursed rubble masonry : In coursed rubble masonry, stones of particular courses are of equal height. The heights of the stone vary from 50 mm to 200 mm. Stones used between the header should not be small than 5 cm in thickness. This type of buildings are used for public buildings, residential buildings etc. Depending on the heights of each course and the thickness of mortar joints,

course rubble masonry is further classified as

a)      course rubble masonry I sort,

b)      course rubble masonry II sort and

c)      course rubble masonry III sort.

Un coursed rubble masonry: In this type of masonry, the courses are not maintained regularly.

The larger stones are laid first and the spaces between them are filled by means of spalls. The wall is brought to level every 300 to 500 mm.

Dry Rubble Masonry : The structure made with stones laid in different courses, without any mortar is called Dry rubble masonry . The stones used in this type of construction should have maximum bedding area.

Random rubble masonry : In this type of masonry, the stones are selected at random. Their size and shape is not considered

Ashlar masonry : In this type of masonry square or rectangular blocks of stones are used. The height of            stones vary from 250 to 300 mm.

Ashlar masonry is further classified

(i) Ashlar fine

(ii) Ashlar rock and quarry fuel

(ii) Ashlar chamfered

(iv) Ashlar facing

Ashlar fine: In this type of stone masonry the stone blocks are finely chisel dressed and then faces are made perfectly the in shape and joints are kept less than 3 mm. The face stones are normally laid as headers and stretcher in alternate courses. The height of stones used in masonry should never be less their breadth.

Ashlar rock: In this type of stone masonry the exposed faces of facing stones, are used as obtained from the quarry. If the stone projection is more than 8 cm, it is hammered to provide a rough surface.

Ashlar chamfered: It is similar to the quarry faced masonry with difference that edged round the exposed faces of each stone, are leveled at an angle of 45^o for a depth of 2.5 cm.

Ashlar facing: In this type the exposed face is constructed with stone masonry and backing is constructed in brick masonry, rubble masonry. The backing and facing are constructed simultaneously the composite construction reduces, the expenditure to a great extent.

Brick Masonry

  Ø  Bricks should be soaked water at least two hour before use.

  Ø  Minimize the use of brick -bats.

  Ø  The height of brick masonry in a day should be less than 1.5 m.

  Ø  The walls should be stopped with a toothed end.

Ø  Finished brick work in cement mortar should be cured 1 to 2 weeks.

  Ø  Flemish bond is weaker than English bond.

King closer: It is a brick which is cut in such a way that the width of one of its end is half of that of a full brick.

Queen closer: It is a term applied to a brick which is half as a full brick. Queen closer is made by cutting a brick lengthwise into two portions.

Beveled closer: It is similar to king closer the only difference that the whole length of the brick is beveled for maintaining half with at one end and full width at the other.

Mitred closer: It is a brick whose one end is cut splayed or mitred for the full width.

Brick bat: It is the portion of a brick cut across the width or a brick cut by some fraction of its length. If a brick cut by half size in it called as half bat and cut by thee quarter size is three quarter bat.

Lap: The horizontal distance between two vertical joints is termed as lap.

Arises: The edges of the bricks are called as arises. Arises should be sharp and unbroken.

Bed joint: Joints parallel to the bed of bricks or stone in a course are termed on bed joints.

Perpends: It is a vertical joint on the face of a wall directly over vertical joints of alternate courses.

Frog: Depressions provided in the face of the brick is called as frog. It forms a key with mortar to prevent sliding.

S.No.	Stone Masonry	Brick Masonry
I	The stones obtained naturally are dressed to a particular shape and used for masonry work.	In this the bricks burnt in kiln and used for masonry work.
2	Stone masonry is very strong.	Strength of brick masonry is lesser than stone masonry.
3	Water tight stone masonry may be constructed.	Like stone masonry water tight masonry work is not possible in Brick masonry.
4	Stone masonry does not have the property of water absorption so this masonry is suitable for bath room and toilets than brick Masonry.	Brick walls are having the property of water absorption. To protect the walls from the dampness cement plastering is necessary. When sewage water is sprinkled on the walls the brick are eroded and attains the powder form.
5	Even though stone masonry is hard but construction is tough.	Construction of brick masonry work is very easy.
6	Bonding property is not much high as III brick masonry and consumption of cement mortar is also high.	Good bonding property is available in brick work. Less quantity of cement or lime mortar is used.
7	Lifting and handling of stones are tough. So speed of masonry work is slow.	As the size of brick is small handling and lifting is easy. So masonry work is faster.
8	In hilly areas stores are highly available so construction cost is low	Other than hilly area cost of brick work is economical.
9	We cannot directly use the stone which are taken from stone quarry. It should be required to some extent so cost becomes high.	We can use the bricks directly from the kiln so cost becomes low.
10	Minimum width of stone masonry should be 30cm construction of stone masonry below this width is tough.	We can construct brick walls from 10cm to 20cm.
11	Heat absorption property is high for stone masonry.	Heat absorption property is not much high.