UNIT II CONSTRUCTION PRACTICES

Specifications, details and sequence of activities and construction co-ordination – Site Clearance – Marking –
Earthwork - masonry – stone masonry – Bond in masonry - concrete hollow block masonry – flooring – damp proof
courses – construction joints – movement and expansion joints – pre cast pavements – Building foundations –
basements – temporary shed – centering and shuttering – slip forms – scaffoldings – de-shuttering forms –
Fabrication and erection of steel trusses – frames – braced domes – laying brick –– weather and water proof – roof
finishes – acoustic and fire protection.

MASONRY:
It is the building of structures from individual units laid in and bound together by mortar; the term
masonry can also refer to the units themselves. The common materials of masonry construction are brick,
stone, marble, granite, travertine, limestone, cast stone, concrete block, glass block, stucco, tile, and cob.
Masonry is generally a highly durable form of construction. However, the materials used, the quality of
the mortar and workmanship, and the pattern in which the units are assembled can significantly affect the
durability of the overall masonry construction. A person who constructs masonry is called a mason or
bricklayer.
Applications
Masonry is commonly used for the walls of buildings, retaining walls and buildings. Brick and concrete
block are the most common types of masonry in use in industrialized nations and may be either weight-
bearing or a veneer. Concrete blocks, especially those with hollow cores, offer various possibilities in
masonry construction. They generally provide great compressive strength, and are best suited to structures
with light transverse loading when the cores remain unfilled. Filling some or all of the cores with concrete
or concrete with steel reinforcement (typically rebar) offers much greater tensile and lateral strength to
structures.
Advantages
 The use of material such as bricks and stones can increase the thermal mass of a building and can
protect the building from fire.
 Most types of masonry typically will not require painting and so can provide a structure with
reduced life-cycle costs.
 Masonry is non-combustible product.
 Masonry walls are more resistant to projectiles, such as debris from hurricanes or tornadoes.
 Masonry structures built in compression preferably with lime mortar can have a useful life of
more than 500 years as compared to 30 to 100 for structures of steel or reinforced concrete.
Disadvantages
 Extreme weather, under certain circumstances, can cause degradation of masonry wall surfaces
due to frost damage.
 Masonry tends to be heavy and must be built upon a strong foundation, such as reinforced
concrete, to avoid settling and cracking.
 Other than concrete, masonry construction does not lend itself well to mechanization, and
requires more skilled labor than stick-framing.
  Masonry consists of loose components and has a low tolerance to oscillation as compared to other
materials such as reinforced concrete, plastics, wood, or metals.
STONE MASONRY AND BRICK STONE MASONRY

Definition:

Rock, that is removed from its natural site and generally, cut or dressed and then finished for building
purposes, is called "Stone" and the art of building the structure with stones as constructional units is
called "Stone Masonry".

Types of Stone Masonry:

Stone masonry may be broadly classified into the following two types:
I. Rubble Masonry
II. Ashlar Masonry
I. Rubble Masonry:
The stone masonry in which either undressed or roughly dressed stone are laid in a suitable mortar is
called rubble masonry. In this masonry the joints are not of uniform thickness. Rubble masonry is further
sub-divided into the following three types:
1. Random rubble masonry
2. Squared rubble masonry
3. Dry rubble masonry
1. Random rubble masonry: The rubble masonry in which either undressed or hammer dressed stones
are used is called random rubble masonry. Further random rubble masonry is also divided into the
following three types:
a. Un coursed random rubble masonry: The random rubble masonry in which stones are laid
without forming courses is known as un coursed random rubble masonry. This is the roughest
and cheapest type of masonry and is of varying appearance. The stones used in this masonry are
of different sizes and shapes. before lying, all projecting corners of stones are slightly knocked
off. Vertical joints are not plumbed, joints are filled and flushed. Large stones are used at corners
and at jambs to increase their strength. Once "through stone" is used for every square meter of
the face area for joining faces and backing.
Suitability: Used for construction of walls of low height in case of ordinary buildings.
 b. Coursed random rubble masonry: The random rubble masonry in which stones are laid in
layers of equal height is called random rubble masonry. In this masonry, the stones are laid in
somewhat level courses. Headers of one coursed height are placed at certain intervals. The stones
are hammer dressed.
Suitability: Used for construction of residential buildings, go downs, boundary walls etc.

2. Squared rubble masonry: The rubble masonry in which the face stones are squared on all joints and
beds by hammer dressing or chisel dressing before their actual laying, is called squared rubble masonry.
There are two types of squared rubble masonry.
a. Coursed Square rubble masonry: The square rubble masonry in which chisel dressed stones
laid in courses is called coarse square rubble masonry. This is a superior variety of rubble
masonry. It consists of stones, which are squared on all joints and laid in courses. The stones are
to be laid in courses of equal layers. and the joints should also be uniform.
Suitability: Used for construction of public buildings, hospitals, schools, markets, modern
residential buildings etc and in hilly areas where good quality of stone is easily available.
 b.Un coursed square rubble masonry: The squared rubble in masonry which hammer dressed
stones are laid without making courses is called un coursed square rubble masonry. It consists of
stones which are squared on all joints and beds by hammer dressing. All the stones to be laid are
of different sizes.
Suitability: Used for construction of ordinary buildings in hilly areas where a good variety of
stones are cheaply available.

3.Dry rubble masonry: The rubble masonry in which stones are laid without using any mortar is called
dry rubble masonry or sometimes shortly as "dry stones". It is an ordinary masonry and is recommended
for constructing walls of height not more than 6m. In case the height is more, three adjacent courses are
laid in squared rubble masonry mortar at 3m intervals.

II. Ashlar masonry:

The stone masonry in which finely dressed stones are laid in cement or lime mortar is known as
ashlars masonry. In this masonry are the courses are of uniform height, all the joints are regular, thin and
have uniform thickness. This type of masonry is much costly as it requires dressing of stones.

Suitability: This masonry is used for heavy structures, architectural buildings, high piers and abutments
of bridges.
Ashlars masonry is further sub divided into the following types:
ne or coarse ashlar masonry
 Ashlar fine or coursed ashlar masonry: In this type of stone masonry stone blocks of same
height in each course are used. Every stone is fine tooled on all sides. Thickness of mortar is
uniform through out. It is an expensive type of stone masonry as it requires heavy labor and
wastage of material while dressing. Satisfactory bond can be obtained in this type of stone
masonry.

 Random coursed ashlar masonry: This type of ashlar masonry consists of fine or coursed ashlar
but the courses are of varying thick nesses, depending upon the character of the building
 Rough tooled ashlar masonry: This type of ashlar masonry the sides of the stones are rough
tooled and dressed with chisels. Thickness of joints is uniform, which does not exceed 6mm.


 Rock or quarry faced ashlar masonry: This type of ashlar masonry is similar to rough tooled
type except that there is chisel-drafted margin left rough on the face which is known as quarry
faced.


 Chamfered ashlar masonry: It is similar to quarry faced except that the edges are beveled or
chamfered to 450 for depth of 2.5 cm or more.
  Block-in course masonry: It is the name given to a class of ashlar masonry which occupies an
intermediate place between rubble and ashlars. The stones are all squared and properly dressed. It
resembles to coursed rubble masonry or rough tooled ashlar masonry.
 Ashlar facing: Ashlar facing is the best type of ashlars masonry. Since this is type of masonry is
very expensive, it is not commonly used throughout the whole thickness of the wall, except in
works of great importance and strength. For economy the facing are built in ashlars and the rest in
rubble.

BRICK MASONRY
 When bricks are laid in mortar in a proper systematic manner, they form a homogeneous mass,
which can withstand forces without disintegration. This mass of the structure, so made by the use of
bricks is called "Brick Masonry" or simply "Brick work".
 Bricks are of uniform size and shape, light in weight, durable, fire resistant, have high resale value,
low maintenance cost and are easily available in plain areas.
 Brick Masonry is commonly used for construction of ordinary as well as important buildings in plain
areas now-a-days.

SOME IMPORTANT TERMS USED IN BRICK MASONRY

(1) BRICK
 An artificial structural element in the form of a rectangular block of clay is called a “Brick ". Bricks
can be manufactured of any required shape and size. The sizes of some standard bricks are given as
follows:
  These sizes are called "Nominal, designated or format sizes" and are used while estimating
the number of bricks in a given volume of structure.
(2) FROG
The depression provided in the face of a brick is called a "Frog".
It is provided in the brick to achieve the following purposes:
(a) To form a key of mortar in between any two adjacent courses of brick work, so as to increase
the lateral strength of the structure.
(b) To reduce the weight of the bricks, so that the bricks can be laid with convenience.
(c) To provide a place for putting the impression of trade-mark or the year of manufacturing of
the bricks.
(3) POSITION OF BRICKS
(a) The position of brick, when laid with its Frog upward in the horizontal plane, is termed as
"Brick on bed".
(b) The position of the brick when laid on its side "9 in x 3 in", with frog in the vertical plane is
called "Brick on edge".
(c) The position of brick when laid on its side "4 1/2 in x 3 in", with frog in the vertical plane is
called " Brick on end".
(4) COURSE
 Each horizontal layer of bricks laid in mortar in a brick work is called a "course".
(5) STRETCHER
Brick, laid with its length horizontal and parallel with the face of the wall or other masonry
member is called a "Stretcher" and a course, in which, all the bricks are laid as Stretchers is
called a “Stretching course" or "Stretcher course".

(6) HEADER
A brick laid, so that only its end shows on the face of a wall is called a "Header" and a course, in
which all the bricks are laid as headers, is known as "Heading Course" or "Header course".
(7) QUOIN
The external corner of the wall is called a "Quoin".
(8) QUOIN BRICK
The brick, which forms the external corner of a wall is known as " Quoin brick".
(9) QUOIN HEADER
A corner header, in the face of wall, which is a stretcher in the side wall is known as "Quoin header".
(10) QUOIN STRETCHER
A corner stretcher in the face of a wall, which is header in the side wall is known as "Quoin stretcher".
(11) BRICK BATS
The pieces of bricks, cut long their length and having width equivalent to that of a full or half
brick are called "Brick bats“.
Some common Brick Bats are shown below:

(12) QUEEN CLOSER

 Queen closer is a brick, which is half as wide as full brick and is made by cutting a whole brick
lengthwise into two portions.
 These are generally used next to the Quoin header for creating bonds in brickwork.
(13) KING CLOSER
 A brick, whose one diagonal piece is cut off one corner by a vertical plane passing through
the center of one end to the center of one side.
 It is actually 7/8 of a full brick but is usually called a 3/4 brick

(14) BEVELED CLOSER

 A brick cut longitudinally along a vertical plane, starting at the middle of one end to the far
corner.
  One quarter of the brick is cut off in this way.
(15) BULL NOSE BRICK
A brick with rounded corners is called a “Bull Nose Brick”
(16) SQUINT BRICKS
 These bricks are used to construct acute (>90 degree) or obtuse (< 90 degree) corners in brick
masonry.
 These are special forms of bricks.

(17) JAMB
The vertical sides of door or window openings provided in a wall are known as "Jambs".
(18) REVEALS
The part of the Jamb opening , which is exposed between a door or window frame and the face or
back of a wall is known as " Reveal".
(19) SILL
The horizontal part (either of timber, concrete, stone, metal, etc) at the bottom of a door or
window, supporting the vertical members of the frame is known as " Sill " and its height window
base from the floor level is known as " Sill level ".
(20) MORTAR
 The paste obtained by mixing a binding material and a fine aggregate in suitable proportions in
addition to water is known as "Mortar".
 Cement and Lime are used as binding materials and Sand, Surkhi, Cinder, etc. are used as fine
aggregates.
 The mortars are named according to the type of binding material used in their preparation such as,
cement mortar, lime mortar, etc.
 The mortar prepared from simple earth is known as "Mud Mortar".
  The mortar not only acts as a cementing bed between any two courses of bricks but also, gives
strength to the structure by holding the individual bricks together to act as a homogenous mass.

BONDS
Bond is the arrangement of bricks or stones in each course, so as to ensure the greatest possible
interlocking and to avoid the continuity of vertical joints in two successive courses, both on the face and
in the body of a wall. Following are the commonly used bricks bonds.

1. Stretcher Bond
2. Header bond
3. English Bond
4. Flemish Bond
5. Common/American/English Garden Wall Bond
6. Flemish Garden Wall Bond
7. Herringbone Bond
and there are many other brick bonds which a designer can design for custom requirements

1. Stretcher Bond
 Easiest bond to lay & it minimizes the amount of cutting required.
 Originally used for single brick walls.
 It is used for cavity walls as less cutting is required.
 Walls are half brick wide.
 No two adjacent vertical joints should be in line.

2. Header bond
 A header is the shorter face of the brick as seen in the elevation. In a standard brick it is 90 mm ×
90 mm face. In header bond brick masonry all the bricks are arranged in the header courses as
shown in Fig. 8.5. This type of bond is useful for the construction of one brick thick walls.
3. English Bond
 Alternative courses of headers and stretchers.
 One header placed centrally above each stretcher.
 This is a very strong bond when the wall is 1 brick thick (or more thicker).
 One of the strongest brickwork patterns.
4. Flemish Bond
 Alternate bricks are placed as header and stretcher in every course.
 Each header is placed centrally between the stretcher immediately above and below. This is not as
strong as the English bond at 1 brick thick .
 It can be successfully applied in cavity wall.
 Brick bats are to be used in walls having thickness equal to an odd multiple of half brick.
5. Common/American/English Garden Wall Bond
 A pattern made like Stretcher bond but with a row of headers replacing every nth course (n is
usually odd). This bond is used for constructing one brick thick garden walls, boundary walls, and
other walls such as outer leaves of cavity walls to provide good appearance.
6. Flemish Garden Wall Bond
 In this bond a header is provided after 3 or 5 stretches in each course.
 This bond is also known as “Sussex or Scotch Bond".

7. RAKING BOND
 The bond in which all the bricks are laid at an angle other than 900 to the facing and backing of
the wall is known as "Raking bond".
 This bond is used for doing inner filling of walls at suitable intervals to improve their longitudinal
strength.
 The angle of rake between any two adjacent courses should be 90 degree to attain maximum
transverse strength of the wall.
 This bond can also be used as paving in case of brick floors, 4 ½ in thick.
 Types of Raking bond
(a) HERRING BONE BOND
 The raking bond in which bricks are laid at an angle of 45 degree , strating at the central line and
proceeding towards the facing and backing of the wall, is called "Herring Bone Bond"
 It is a purely decorative bond. It is used in floor and wall panels

(b) DIAGONAL BOND

 The raking bond in which bricks are laid starting from the corner in parallel rows inclined to the
facing and backing of the wall is known as "Diagonal bond".

Comparison of English Bond and Flemish bond

Sr No. English Bonds Flemish bond

1 This bond consists of headers and stretchers laid This bond consists of headers and stretchers
in alternative courses. laid alternatively in each course.

2 It is strongest of all the bonds. It is less strong for walls having thickness
more than 13 ½ inches.
3 It provides rough appearance especially for one It provides good appearance for all thickness
brick thick walls. of walls.

4 There are no noticeable continuous vertical There are partly continuous vertical joints in
joints in the structure built in this bond. the structure built in this bond.

5 Much attention is not required in providing this Special attention is required in providing this
bond. bond.

6 Progress of work is more. Progress of work is less.

7 It is costly because the use of brick bats is not It is economical because brick bats are
allowed. allowed for forming this bind.

COMPARISON BETWEEN BRICK MASONRY AND STONE MASONRY

(1) Stone is stronger and more durable than brick and for public buildings; it is decidedly more suitable
than brick. It reflects strength in every inch of it. It is in tune with nature. Its color improves and looks
more serene with age. On the other hand, brick is an artificial product made as a copy of stone. It is
flimsy material and plastering is only a camouflage for its defects.
(2) Stone is water proof. On the other hand, Brick absorbs moisture and with dampness certain salts rise
in the walls from the ground and cause disintegration of bricks. Especially brick should not be allowed
to come in contact with urine or sewage and in such places it must always be covered with cement plaster
or any other protective coat.
(3) Brick offers greater facility for ornamental work in plaster as a rough shape can first be given to it
by means of any tool. This is not so in case of stones.
(4) Plaster does not stick so well to stones as it does to brick.
(5) On account of the regular shape and uniform size of brick, a proper bond can be obtained with
comparative ease.
(6) Due to the handy size of brick, brick masonry can be more rapidly constructed than stone masonry.
(7) Brick wall requires a fixed quantity of mortar and even with careless masons, the regular shape of
the brick considerably reduces the possibility of hollows being left in the body of the wall. This is not so
with some stone walls.
(8) It is possible to build brick walls of any thickness e.g., 4 1/2 in, 3 in, 9 in, 13 1/2 inch etc. Whereas,
the minimum thickness of ordinary stone wall is 15 in. Stone walls of a smaller thickness than 15 in, have
to be constructed with properly dressed stones, which involves a comparatively high cost.
(9) Brick does not absorb as much heat as stone does. So, brick is more fire resistant than stone.