Transcript File

BUILDING CONSTRUCTION
CHAPTER 01:
MASONRY
BRICK MASONRY
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
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:
SOME IMPORTANT TERMS USED IN BRICK MASONRY
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These sizes are called "Nominal, designated or
format sizes" and are used while estimating the
number of bricks in a given volume of structure.
The actual sizes in which bricks are
manufactured, are slightly smaller to allow for the
layer of mortar present all around the brick,
usually taken as 3/8 in thick.
The Actual or Work size of English standard
brick, which is mostly used in Pakistan, is usually
taken as 8 5/8 in 4 1/8 in x 2 5/8 in.
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(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.
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(3) POSITION OF BRICKS
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(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".
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(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".
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(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".
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(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".
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(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:
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(12) QUEEN CLOSER
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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
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(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.
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(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 ".
SOME IMPORTANT TERMS USED IN BRICK MASONRY
(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".
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Cement and Lime are used as binding materials and Sand, Surkhi,
Cinder, etc. are used as fine aggregates.
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The mortars are named according to the type of binding material
used in their preparation such as, cement mortar, lime mortar, etc.
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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.
OBJECTIVES OF BONDS
A bond is provided to achieve the following objectives:
(a) The primary objective of providing a bond is to break the continuity of the
vertical joints in the successive courses both in the length and thickness of
masonry structure. As a result, the structure will act as a bounded mass
and its load will be transmitted uniformly to the foundations.
(b) To ensure longitudinal and lateral strength of the structure.
(c) To provide pleasing appearance by laying bricks symmetrically.
(d) To do masonry work quickly by engaging more masons on a job at a time.
TYPES OF BONDS
(1) ENGLISH BOND
The bond, in which headers and stretchers are laid in
alternate courses, is called "English bond".
TYPES OF BONDS
ENGLISH BOND
The following are the salient features of English bond:
(i) Headers and stretchers are laid in alternate courses.
(ii) In each heading course, a queen closer is placed next
to quoin header and the remaining bricks are laid as
headers.
(iii) Every alternate header in a course comes centrally
over the joint between two stretchers in the course
below, giving an approximate lap of 2 ¼ in.
TYPES OF BONDS
ENGLISH BOND
(iv) The same course will show headers or stretchers on face and back, if
the thickness of the wall is an even multiple of half bricks (e.g. 9 in, 18
in, 27 in, etc.)
(v) The same course will show headers on the face and stretchers on the
back and vice versa, if the thickness of the wall is an odd multiple of half
brick. (13 1/2 in , 22 1/2 in , etc )
(vi) The middle portion of the thicker walls consists entirely of headers.
(vii) Every transverse joint is continuous from face to face.
TYPES OF BONDS
(2) FLEMISH BOND
The bond, in which headers and stretchers are laid alternately in the same
course, is called "Flemish bond".
TYPES OF BONDS
The following are the salient features of Flemish bond:
(i) Headers and stretchers are laid alternately in the
same course.
(ii) Every header in each course lies centrally over
every stretcher of the underlying course.
(iii) In every alternate course a queen closer is placed
next to quoin header, so as to provide a lap of
approximately 2 1/4 in.
(iv) Brick bats are to be used in walls having thickness
equal to an odd multiple of half brick.
Comparison of English Bond and Flemish bond
Sr
No
.
English Bonds
Flemish bond
1
This bond consists of headers and stretchers
laid in alternative courses.
This bond consists of headers and
stretchers 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 brick thick walls.
It provides good appearance for all
thickness of walls.
4
There are no noticeable continuous vertical
joints in the structure built in this bond.
There are partly continuous vertical
joints in the structure built in this bond.
5
Much attention is not required in providing
this bond.
Special attention is required in providing
this bond.
6
Progress of work is more.
Progress of work is less.
7
It is costly because the use of brick bats is
not allowed.
It is economical because brick bats are
allowed for forming this bind.
TYPES OF FLEMISH BONDS
(a) DOUBLE FLEMISH BOND
The bond in which headers and stretchers
are laid alternately in each course, both in
the face and back of the wall, is called
Double Flemish Bond.
TYPES OF FlEMISH BONDS
(b) SINGLE FLEMISH BOND
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The bond provided in a wall with Flemish bond in facing and
English bond in backing is called "Single Flemish bond" or
"Cross bond".
This bond combines the advantages of both English and Flemish
bonds and simultaneously eliminates their disadvantages.
This bond is recommended where costly bricks are specified for
facing in order to provide good appearance to the wall. Also, it
can be made more economical by using cheap quality of bricks
on the back of wall.
On the other hand, it weakens the overall strength of the wall
because of maximum use of brick and existence of continuous
vertical joints. Also, it can not be provided in walls having
thickness less than 13 ½ in.
TYPES OF BONDS
(3) HEADING BOND
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The bond in which all the bricks are laid as headers in every course
of a wall is called "Heading bond".
3/4 bats are laid as quoin bricks in the alternate courses to break the
continuity of vertical joints, which increases the transverse strength
but weakens the longitudinal strength of the wall.
This bond is commonly used for constructing steining of wells,
footings of walls and columns, corbels, cornices, etc.
TYPES OF BONDS
(4) STRETCHING BOND

The bond in which all the bricks are laid as stretchers in every course
is called "Stretching bond”.

This bond is provided for constructing 4 ½ in thick partition walls.
TYPES OF BONDS
(5) GARDEN WALL BOND
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.
TYPES OF GARDEN WALL BONDS
(a) ENGLISH GARDEN WALL BOND
The garden wall bond in which a heading course is
provided after 3 or 5 stretching courses is called
"English Garden Wall Bond"
TYPES OF GARDEN WALL BONDS
(b) 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".
TYPES OF BONDS
(6) RAKING BOND
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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".
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This bond is used for doing inner filling of walls at suitable
intervals to improve their longitudinal strength.
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The angle of rake between any two adjacent courses should be
90 degree to attain maximum transverse strength of the wall.
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This bond can also be used as paving in case of brick floors, 4 ½
in thick.
TYPES OF RAKING BONDS
(a) HERRING BONE BOND
 The raking bond in which bricks are laid at an angle
of 45 degree , starting at the central line and
proceeding towards the facing and backing of the
wall, is called "Herring Bone Bond"
TYPES OF RAKING BONDS
(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".
TYPES OF BONDS
(7) HOOP IRON BOND
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The bond in which, after every fourth or fifth course of
masonry, reinforcement in the form of longitudinal ties is
provided for additional strength of the wall, is called " Hoop
Iron Bond".
This bond is provided for constructing 4 1/2 in thick partition
walls
TYPES OF BONDS
(8) MONK BOND
 This bond in which two stretchers and one header
are laid alternately in each course is called
"Monk bond".
 This bond is used in the construction of boundary
walls.
TYPES OF BONDS
(9) RHOM BOND
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This bond in which brick/ tiles are laid in order to have straight
horizontal and vertical joints in the facing is called "Rhom
bond".
This bond is used only in facing work to provide architectural
beauty.
STONE MASONRY
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".
MAIN TYPES OF STONE MASONRY
(1) Rubble Masonry
(2) Ashlar Masonry
RUBBLE MASONRY
•
The stone masonry in which either undressed
or roughly dressed stones are laid is called
"Rubble masonry".
•
In this masonry, the joints of mortar are not of
uniform thickness.
TYPES OF RUBBLE MASONRY
(a) Random Rubble masonry
(i) Uncoursed random rubble Masonry
(ii) Built to courses random rubble Masonry
(b) Squared Rubble
(i) Uncoursed squared rubble Masonry
(ii) Built to courses squared rubble Masonry
(iii) Regular coursed squared rubble Masonry
(c) Dry rubble masonry
(a) RANDOM RUBBLE MASONRY
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The rubble masonry in which either undressed or
hammer dressed stones are used is called "Random
Rubble Masonry".
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The strength of this masonary depends upon the bond
between the stones.

The bond should be sound both transversely and
longitudinally.

Transverse bond is obtained by the liberal use of
"Bonders" and "Throughs"
Bonders are stones, which reach beyond
the middle of the wall from each face to
overlap in the center (Dog’s Teeth Bond).
THROUGHS are stones, which extend the
full thickness of the wall.
Note: Throughs should not be used in the
external walls, as moisture may be
conducted through them and cause
dampness on the internal face.
(i) UNCOURSED RANDOM RUBBLE MASONRY

The random rubble masonry, in which all the stones are laid without
forming courses, is known as "Uncoursed Random Rubble
masonry".

This masonry is the cheapest and roughest type of masonry.
The stones to be used in this masonry are of different sizes and
shapes.
Larger stones are used at corners and at jambs to increase their
strength.
In general, stones are laid with their longer axis roughly horizontal
and along the length of the wall.
The only shaping of stones that is executed is the removal of
inconvenient corners or projections with a hammer.
This type of masonry is used for constructing walls of low height in
case of ordinary buildings
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(ii) BUILT TO COURSES RANDOM RUBBLE
MASONRY

In this type of masonry, the work is roughly leveled
up to form courses, varying from 12 to 18 in thick.

In each course, headers of one course height are
placed at certain intervals.

This type of masonry is used to construct residential
buildings, godowns, boundary walls, etc
(b) SQUARED RUBBLE MASONRY

The Rubble masonry in which the face stones are
roughly squared by hammer dressing or chisel
dressing, before their actual laying is called "Squared
Rubble masonry".

There are three Types of squared rubble masonry:
(i) UNCOURSED SQUARED RUBBLE
MASONRY

In this type of squared rubble masonry, the
stones are roughly squared and built without
continuous horizontal courses .

It is used for ordinary buildings in hilly areas,
where a good variety of stones are easily and
cheaply available.
(ii) BUILT TO COURSES SQUARED
RUBBLE MASONRY
The stones are roughly squared and laid in
courses to bond in with the larger quoin
stones.
(iii) REGULAR COURSED SQUARED
RUBBLE MASONRY

This type of masonry is built in courses of varying
height but the stones in any one course are of the
same depth.

It is mostly used in public buildings, hospitals,
schools, markets, modern residential buildings and
in hilly areas, where a good quality of stone is easily
and cheaply available.
(c) DRY RUBBLE MASONRY

The rubble masonry in which stones are laid without
using any mortar is known as " Dry Rubble
Masonry".

It is an ordinary masonry and is recommended for
constructing walls of height not more than 18 ft.

In case, the height is more, three adjacent courses
are laid in Squared rubble masonry, in mortar at 9 ft
interval.
(2) ASHLAR MASONRY

The stone masonry in which finely dressed stones are
laid in cement or lime mortar, is known as "Ashlar
Masonry".

In this masonry all the joints are regular, thin, and of
uniform thickness.

This type of masonry is costly in construction as
involves heavy cost of dressing of stones.

This masonry is used for heavy structures, arches,
architectural buildings, high piers, abutments of
bridges, etc.
TYPES OF ASHLAR MASONRY
(a) ASHLER FINE / COURSED ASHLAR
MASONRY

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
In this type of masonry stone blocks of same
height are used in each course.
Every stone is fine tooled on all sides.
Thickness of Mortar joint is less than 1/16 in
and is uniform through out.
(b) RANDOM COURSED ASHLAR MASONRY
This type of Ashlar masonry consists of fine
or coursed Ashlar masonry but the courses
are of varying thickness, depending upon the
character of the building.
(c) ROUGH TOOLED ASHLER
MASONRY

In this type Ashler masonry, the sides of the
stones are rough tooled and dressed with
chisels.

Thickness of joints does not exceed ¼ in.
(d) QUARRY FACED ASHLAR MASONRY
This type of Ashlar masonry is similar to rough tooled Ashlar masonry
but there is chisel-drafted margin left rough on the face.
(e) CHAMFERED ASHLAR MASONRY
It is similar to Quarry faced except that the
edges are given a slope of 45 degree for a
depth of 1 in. or more.
(f) ASHLAR FACING

In order to reduce the cost and to give the
appearance of Ashlar facing to the wall it is
usual practice to construct walls with facing of
Ashlar and backing of Rubble or brick masonry.
Such walls are also called “Compound or
Composite masonry walls”.

If the backing is of Rubble masonry, It is called
“Rubble Ashlar" and if the backing is of brick
work the masonry is termed as “Brick Ashlar”
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.
COMPARISON BETWEEN BRICK MASONRY AND
STONE MASONRY
(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.
COMPARISON BETWEEN BRICK MASONRY AND
STONE MASONRY
(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.
COMPARISON BETWEEN BRICK MASONRY AND
STONE MASONRY
(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.
COMPARISON BETWEEN BRICK MASONRY AND
STONE MASONRY
(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.
SITE SELECTION

The site of a building greatly affects its
planning, design and construction.

It may be selected as required or accepted as
available.

The selection of site depends upon the purpose
for which the proposed building is to be
constructed.
FACTORS TO BE CONSIDERED WHILE SITE
SELECTION
(1) LEVEL OF THE SITE
The level of the site must be higher than that
of its surroundings, so as to provide good
drainage.
(2) CLIMATIC CONDITIONS
The intensity of rainfall and sub-soil water
level should be low, so as to avoid dampness
in the building.
FACTORS TO BE CONSIDERED WHILE SITE
SELECTION
(3) SUB-SOIL CONDITIONS
A hard stratum should be available at a reasonable depth (3ft to
4 ft from the ground level), so as, to construct the foundations of
the building safely and economically.
(4) AVAILABILITY OF MODERN AMENITIES
The site must be within municipal limits, so that, modern
amenities like, water supply, electricity, sewerage, roads, etc.
can be made available with more ease, if there is no provisions
at present.
FACTORS TO BE CONSIDERED WHILE SITE
SELECTION
(5) AVAILABILITY OF OTHER FACILITIES
The site should provide an easy access from the nearest road
and offer sufficient light and air. There should be good and cheap
transport facilities available near the site. It is always better, if
public services like, fire brigade, police station, etc, are also not
very far off from the site.
(6) SURROUNDINGS
The situation and surroundings of the site must be such as to suit
the purpose for which the building is to be constructed. Each type
of building requires different surroundings, than for others.
GENERAL PRECAUTIONS IN SELECTION
OF SITE
(1) The site consisting of reclaimed soil (made useful for
cultivation) should be avoided, as far as possible.
(2) The site must not be located in water logged areas or near
the bank of a river.
(3) Old quarry sites must be avoided, as far as possible.
(4) The site for a residential building should be away from the
area causing foul odor or smoke nuisance due to industrial
buildings.
GENERAL PRECAUTIONS IN SELECTION
OF SITE
(5) The site for a residential building, school or
hospital should be away from noisy areas.
(6) There should be no disabling easement.
(Easement is a right, which a person may have
over another man's land by law, such as, the
right to walk over it or to run a pipe through it).
ORIENTATION OF BUILDINGS

The placing of a building with respect to the geographical directions,
the direction of the wind, and the path of the sun, is known as the
"Orientation of buildings".

The building should be placed in such a way that it derives
maximum benefit from sun, air, rain, and nature and at the same
time, it is protected from their harmful effects.

The orientation also includes the arrangement of rooms of a
building, so as to provide natural comforts to the residents.

Orientation requires first priority after selection of site, for proper
planning and design of a building.
FACTORS AFFECTING ORIENTATION OF
BUILDINGS
(1) SURROUNDING OF THE SITE
The building is to be orientated to suit the
surroundings of the site.
(2) PROXIMITY OF A ROAD OR STREET
The building should be so orientated, as to
provide easy approach from the nearby road or
street.
FACTORS AFFECTING ORIENTATION OF
BUILDINGS
(3) THE SUN

The sun is a source of natural light and temperature.

Sunlight is a powerful agent for killing the germs of harmful
diseases like, tuberculosis, typhoid, cholera, etc., which may,
otherwise, breed in the dark and damp corners of a building.

It is, therefore, essential to orientate the building such that the
sun rays may fall sufficiently on the building and enters the
building through doors and windows. However in summer, the
building should also be protected from its severe heat.
FACTORS AFFECTING ORIENTATION OF
BUILDINGS
(4) WIND


The building should be so orientated that cool breeze enters the
bedrooms during night in summer but not in winter.
It should also prevent direct entry of wind of heavy intensity into the
building, so as to protect the residents from dust nuisance.
(5) RAIN


The building should be so orientated, so as to prevent entry of rain
inside the rooms.
It should also provide minimum portion of the building subjected to
direct showers of rain, so as to prevent dampness inside the
building.
ORIENTATION IN DIFFERENT REGIONS

The climatic conditions, intensity of sun and
direction of wind differ from region to region. It is,
therefore, not possible to follow a rigid method, with
regard to the orientation of buildings.

In general the Earth's surface is divided into three
different regions with respect to the orientation of
buildings. In these regions, the orientation is
discussed separately
(1) HOT AND ARID REGION

In these regions, the climate is extreme; the temperature ranges
from 50 C0 maximum to 36 C0 minimum, or, more or less.

Cloudless sky, low humidity, and high incidence of Sun's glare
are the main features.

The sunny areas are hot and dry in the day time and cool to cold
at night.

As far as possible, the building should be protected from day
time heat and glare during summer and at the same time, the
rate of heat loss at night during winter should be reduced.

In these regions the building should be oriented for the Sun, not
for wind as in humid regions.
HOT AND ARID REGION (ctd)
The following points should be kept in mind while orientating
building in such areas:

To minimize the heat gain during summer and take benefit for
solar heat during winter, the longer walls should face north and
south and shorter walls, east and west, so the least wall area is
exposed to the slanting rays of Sun during fore noon and
afternoon.
In other words, we can say that the longer axis of building should
run east west, so as to avoid excessive heat from west side.
HOT AND ARID REGION (ctd)

Provision of projections on the southern walls will
give sufficient shade to the walls during summer and
provision of windows and openings on the southern
wall will allow sunrays to enter into rooms during
winter, because the Sun's altitude is high in
summers and low in winters.

Verandahs are desired on the south for protection
from heat in summers and, also, for sitting out
purposes in winter to enjoy the Sun's heat.
HOT AND ARID REGION (ctd)

Openings in the west should be small and should be properly
orientated. ( To save cost of verandah on the west, the
afternoon's Sun may be kept off by providing Louvers, which are
ventilators, sometimes provided in windows also, in which
horizontal sloping slats allow ventilation but exclude rain and
Sun's rays.)

A small tilt in the axis of the building must be given away from the
west towards the south (facing near about north-west), to get
maximum benefit of breeze during rainy season, autumn, and
spring to ensure comfort and proper ventilation.
(2) HOT AND HUMID REGION

In this region the climate is humid, temperature in
summer is moderately high and rainfall is heavy.

The prime object for orientation and design of
buildings in this region is to provide free air
movement through the building and to prevent the
temperature rise of its inside surface above the
shade temperature.
HOT AND HUMID REGION (ctd)
The following aspects should be considered while
designing buildings in these areas:

The building should face the direction of the
prevailing wind to obtain maximum benefit of the air
movement.

A tilt, up to 45 degree may be allowed, if required,
for which the loss of efficiency is only up to 20%.

Window sills should be low to ensure maximum
ventilation at the normal living level.
HOT AND HUMID REGION (ctd)

Walls should be shaded from the sun, so as to
prevent the temperature rise.

Protection of openings against rain is also
necessary.

Building should normally have open planning, as far
as possible. They should be of one room thickness,
so as to ensure thorough ventilation.
(3) HILLY REGIONS

In these regions, temperature is usually much
low and cold dominates according to the
increasing altitude.

There is marked drop in the temperature
during night.
HILLY REGIONS (ctd)
The following points should be kept in mind while
orientating building in such areas:
(1) The buildings should be located in the southern
slope of the hill, as they receive maximum sunshine
for the greatest duration of time.
(2) The opening should be placed as to allow
sunshine inside the building.
HILLY REGIONS (ctd)
(3) A massive structure with high heat capacity is
useful because the heat, it stores during the day is
welcome, except in very hot day.
(4) It is necessary to provide ceilings of good
thermal insulation to reduce loss of heat by radiation
during night.
(5) In areas, with heavy snowfall, the roof should be
kept sloping to prevent accumulation of snow.
PRE-CONSTRUCTION SITE
WORKS
(1) SITE SURVEY
(1) First of all site is surveyed and topographical details
are drawn on the site plan. If the area is small,
topographical details are drawn by metal chains but if
it is large, then plane table and theodolite are used
for this purpose.
(2) Contouring is done by any suitable method of
contouring and the contours are drawn on the site
plan.
(3) Following the contour map, site is leveled doing
necessary cuttings and fillings with the help of any
suitable machinery.
SITE SURVEY
(4) The datum level is set out.
 It is a level marked on the sections of the
drawings, from which all heights and depths
are marked in figures.
 This level is marked by the architect.
 The datum is usually taken as the surface of
the finished ground floor, abbreviated on the
working drawing as F.F.L.
 It is set out by a leveling instrument.
 A peg is driven into the ground such that its
top is at the F.F.L.
SITE SURVEY
(5) The ground floor plan is marked on the
ground.
 First of all centre lines of all walls are marked
on the ground.
 Right angles are taken by cross staff, optical
square or more precisely, by a Theodolite.
 The lines showing the intended lines of
foundation trenches are marked by driving
wooden pegs along these lines.
(2) PROFILE BOARDS

These are horizontal wooden boards fixed on
edge at the datum level, outside the
foundation dig for a building.

The level at which these are fixed is usually
basement or ground floor or a convenient no
of feet, above or below it.
PROFILE BOARDS

Nails or saw cuts in the top edge of these
boards show the dig lines, footing lines, walls
lines and other building lines, for setting out the
lower part of the building.

One profile board is set at end of each line, i.e.,
two for each corner, so that strings can be
stretched between the nails to show any
required line at any time.

Bricks are then laid in the foundation by plum
bob from the extended strings.
(3) REMOVAL OF TOP SOIL

Before the foundation trenches are excavated, the
surface vegetation, roots, plants, shrubs and usually
all the top soil up to a depth of 150 mm to 300 mm will
have to be removed, from the area of the site to be
covered by the building.

This is done to ensure that the ground, upon which the
structure is to be built, will be sterile (free from
decomposable material i.e., organic material).

The removed top soil is valuable for subsequent use in
the garden lay-out.
(4) SITE DRAINAGE

The building regulations also require that subsoil of any site to be used for building must be
effectively drained.

If the natural drainage of surface water through
the ground is not sufficient, a line of agricultural
drain pipes (porous pipes) can be laid on the
uphill side of the site to intercept ground water
that would, otherwise, flow towards building.
(5) EXCAVATION

When the setting out is completed and the profiles are in position,
excavation of the trenches for the foundation is started.

The width of the trench is read off from the profiles and the depth of the
trench depends upon finding a suitable sub-soil to give a firm bearing
capacity (according to design).

The foundation concrete must also be below the depth at which it will
not be affected by seasonal movement of the sub-soil (according to
design).

It is now common practice to use earth moving machines for
excavations on all contracts except on isolated small sites.
EXCAVATION

Machines, which are in most common use are
Hydraulic Diggers for excavation trenches, a Tractor
Shovel for reducing levels by excavation and a
Dumper for transporting soil from the site.

When soil has been tipped by the Digger, it can be
lifted by the Tractor Shovel and put into the Dumper,
to be carried away and discharged, where ever it is
required for making up levels on the site.

Soil, which is used in this way for filling must be placed
in layers, well compacted and allowed to settle for
many months, so that it will not subside later, if built
upon.
(6) SAFETY IN EXCAVATION




Accidents in excavation are frequent and include a high
proportion of causalities.
One cubic meter of soil weighs more than a ton and
falling through only a short distance, even a half cubic
meter of soil is sufficient to crush and kill a workman.
Great care should be taken to support the excavation,
adequately
This is done by "Timbering of Trenches", which is the
process of supporting the sides of trenches by means of
some wooden or steel members. The timbering is
extended to the full depth of the trenches. .
Timbering of Trenches
The various members used in timbering are:(i) POLING BOARDS
 The members placed vertically on the sides
of trenches directly or after providing sheeting
are known as Poling boards.
 The size of poling boards may vary from 1.75
cm x 32 cm. to 22.5 cm. x 4 cm.
Timbering of trenches in Hard Soil
(With a central strut to each pair of Poling Boards)
Timbering of trenches in Hard Soil
(With two struts to each pair of Poling Boards)
(ii) WALING, WALES OR PLANKS

The members placed horizontally on sides of
the trenches or against Poling boards are
known as Walings, wales or planks.

The various sizes of Walings are 10 x 7.5, 10
x 10, 15 x 15, 17.5 x 5, 22.5 x 5, 22.5 x 7.5
cm.
Their length may vary from 2.5 to 4.5 m.

(iii) STRUTS

The horizontal members of timber driven across the
trenches between Poling boards or Walings are
known as Struts.

The Struts are driven at a minimum distance of 2 m
centre to centre.

The Struts may be circular , having diameter 7.5 m
to 12.5 cm. or square 7.5 cm. to 10 x 10 cm. in
section.
Timbering of trenches in Moderately Hard Soil
(With Walings strutted at alternate Poling Boards )
Timbering of trenches in Moderately Hard Soil
(With a central Waling strutted at every fourth Poling Board)
Timbering of trenches in Moderately Hard Soil
(With a simple Waling strutted at 2 m interval)
(iii) SHEETING

The members which are placed horizontally or vertically
close to the sides of the trenches for supporting their
sides are called Sheeting.

The length of sheeting may vary from 2.5 to 4.5 m.

The horizontal sheeting is supported by Poling boards
and the vertical sheeting by Waling.
Timbering of trenches in Loose Soil
(With horizontal sheeting)
Timbering of trenches in Loose Soil
(With vertical sheeting)
(iv) RUNNERS

The members which are vertically placed behind the
Walings instead of the Poling boards are called Runners.

The Runners are long planks about 7.5 cm. thick and 1.75
to 22.5 cm wide.

They are pointed at their lower end and sometimes
provided with an iron shoe and iron cap.
Timbering of
trenches in very
loose soil
(With Runners)
DAMPNESS
The access or penetration of moisture
content inside a building through its walls,
floors, or roof is known as DAMPNESS.
SOURCES OF DAMPNESS

Damp rising from the soil either through the bottom or
through the ground surface, adjacent to the walls.

Moisture penetrating the walls as a result of rain beating
on them during continued wet weather.

Moisture penetrating into the building through defective
construction, such as rain water pipes, leaking roofs,
leaking or choked gutters, etc.

Damp rising from the ground either because there is no
damp proof course or because the existing D.P.C. has
been bridged by the earth outside, being banked up to
form a flower bed or an other purpose.
ILL EFFECTS OF DAMPNESS

It causes rots to the wooden members provided in the
building.

It causes corrosion of the metals, used in the
construction of a building.

It causes peeling off and removal of plaster.

It causes paints to get blistered and bleached and the
surface thus gets disfigured.

It causes floors of the building to remain ugly, since they
cannot be cleaned well.
ILL EFFECTS OF DAMPNESS






Carpets if used on the floors of a damped building, gets
destroyed earlier.
All electric installations get destroyed.
It reduces the life of the structure as a whole.
When dampness rises into brickwork, certain salts
dissolved in it also rise with it and appear in the form of
white deposit on the wall surface due to which brickwork
disintegrates and falls to powder.
It causes unhygienic conditions for the occupants of the
building and affects adversely their health.
Dampness produces unpleasant smell, foul air, mildew
fungus, which makes it impossible to store supplies of
household goods.
CAUSES OF DAMPNESS

RAIN PENETRATION
Properly constructed walls offer considerable resistance
to rain penetration but its rapid penetration takes place
through the joints and porous bricks or stones. Rain
penetration is also possible through the roof
components, cracks, and joints b/w the walls and the
roof.

LEVEL OF THE SITE
Structures built on a higher ground can be drained off
easily and hence they are less liable to dampness. But
low lying areas cannot be easily drained off and thus
causes dampness in the structure.
CAUSES OF DAMPNESS

DRAINABILITY OF THE SITE
Gravel and sandy soil allow water to pass through
easily whereas clayey soils retain moisture and also
causes dampness due to capillary rise.

CLIMATIC CONDITIONS
Dampness is also caused due to the condensation of
moisture present in the atmosphere under very cold
climate. Condensation of the atmospheric moisture
can be identified by the drops of moisture present on
the ceilings, walls, floors etc.
CAUSES OF DAMPNESS (- ctd -)


DEFECTIVE ORIENTATION
The building having its walls subjected to direct showers of rain or
getting less direct sun rays, due to defective orientation is liable to
dampness.
MOISTURE ENTRAPPED DURING CONSTRUCTION
Walls while being constructed are in wet conditions. These may
persist moisture for a long period after the construction is over due to
the use of salty or alkaline water, which causes dampness in the
building.

DEFECTIVE MATERIALS
Dampness is also caused due to soakage of moisture by the
defective materials like porous bricks, soft stones, etc. especially
when they are used in external walls.

DEFECTIVE CONSTRUCTION
In case, there is any leakage in the sewers, down water pipes,
kitchens, bathrooms, etc., it will be causing dampness in the
building.
PREVENTION OF DAMPNESS
PRECAUTIONS
 Select a sit to make sure that the first point at which water
is struck in a pit is at least 10ft below the surface of the
ground even in the wet season.

Make the ground surface surrounding the building slope
away from the house so that rain water drains away, before
it has time to collect.

If the building is on a hill side, make sure that the land
above the house is adequately drained around the building
and not through it
METHODS
The following are the methods that can be adapted for the prevention of
dampness in the buildings:
(1) BY SURFACE TREATMENT
The surface treatment consists in filling or blinding the pores of
the material exposed to moisture by painting a water-repellent
material over the surface.
Some of the materials employed are:
Sodium or potassium silicate, aluminium or zinc sulphates,
barium hydroxide and magnesium sulphate in alternate
applications, soft soap and alum also in alternate applications,
lime and linseed oil, coal-tar, bitumen, waxes and fats,
shellacs, resins and gums etc.
(2) BY INTEGRAL TREATMENT

The integral treatment consists in adding certain components
to the concrete or mortar during the process of mixing, to make
it more dense by filling the pores through chemical action or
mechanical effect.

For example, compounds like chalk, talc, fuller’s earth etc. act
mechanically and compounds like alkaline silicates, aluminium
or zinc sulphates, calcium, aluminium or ammonium chlorides,
iron fillings etc. act chemically.

It 5% soap is added in the water to be used for preparing the
mortar, the pores get clogged and coating of water repellent
substance stick to the wall surface which makes it sufficiently
damp proof.
(3) BY SPECIAL CONSTRUCTIONAL TECHNIQUES

By constructing the external walls of sufficient thickness.

By using the bricks of good quality for constructing the external
walls.

By building the walls in rich cement mortar.

By providing string courses and cornices.

By fixing down water pipes sufficiently so that water may not leak
through the junction of walls and roof.

By constructing hollow brick walls. ( these walls are built, usually
with a thick skin of 9in inside, the air space of about 2in between
and the outer skin of 4 ½ in. outside. The two skins are boned
together by means of galvanized iron wall ties).
(4) BY PROVIDING A DAMP PROOF COURSE
The continuous layer of an impervious
material, which is provided in between the
source of dampness and part of the
structure is called a Damp Proof Course.
BY PROVIDING A DAMP PROOF COURSE
Damp proof course is of two types:
(1)
HORIZONTAL DPC

It is provided in the walls at plinth level in the form of 1 ½ in. thick
layer of 1:2:4 cement concrete covered with two coat of hot
bitumen or a polythene sheet or metal sheets of lead, copper or
aluminum.

It is also provided in the roofs in the form of two coats of hot
bitumen, bitumen felt, mastic asphalt or sheets of polythene, lead,
copper, or aluminum over the R.C.C. slab.

Horizontal D.P.C. is also provided in floors if the sub-soil water
table is high and moisture is likely to rise in the floors by seepage,
added by the capillary action of the soil.
BY PROVIDING A DAMP PROOF COURSE
(2) VERTICAL DPC

Vertical D.P.C. is mostly provided in the external
walls in the form of ¾ in. thick 1:3 cement sand
plaster, coated with two washings of hot bitumen.

It is also provided to prevent the dampness into the
walls of the basements from the adjacent soils.
D.P.C. IN BASEMENTS (- ctd -)

As basements are built below ground level, these are
most likely to be attacked by dampness from the soil
below as well as from outside the walls.

A typical basement section showing the damp proof
courses is shown in fig-119.

If the head of the water below the level of the floor is
high, a layer of gravel 4 ½ in. thick, is laid under the
bottom of concrete of floor as shown in fig-120.

Also, gravel is filed between the walls of the basement
and adjacent soil.
D.P.C. IN BASEMENTS

The gravel under the floor collects the seepage water and delivers it
to the gravel outside the external walls, through the communicating
pipes, buried horizontally through the concrete foundation walls.

Drain pipes or footing drains are laid around the footing buried
inside the gravel.

These footing drains lead the seepage water to a natural drain, if
nearby, or to a dry well.

A dry well is a pit excavated in permeable soil or one having its
bottom in such soil and filled with gravel or crushed rock.

If permeable soil is not present nearby, the water is pumped out of
dry wells by hand pumps or other techniques.
The End