6
Masonry-2: Brick Masonry
61. INTRODUCTION
Rrick masonry
1s
made of brick
units, bonded together
mponents of brick masonry are therefore
Bricks
i e Mortar
with mortar.
Two essential
The mortar used for brick masonry should have the same H6
characteristics as discussed
in Chapter 5 for stone masonry. Mortar acts as a cementing material and unites the
inividual brick units together
to act as
may_ be used in brick masonry.
Cement mortar
homogeneous
2
Cement-lime mortar
Mud mortar
5
a
4
mass.
Following types of mortar
Lime mortar
Lime-surkhi mortar and
Mud mortar is used only for low-rise buildings which carry light loads. Cement
mortars are used for high-rise buildings, where strength is of prime importance. Linme
mortar and lime-surkhi mortars are used for all types of construction.
Bricks are manufactured by moulding clay in rectangular blocks of uniform predetermined size, drying them and then burning them in a kiln. Clay is a plastic earth,
constituted largely of sand and alumina with traces of chalk, iron, manganese dioxide
etc. Good bricks should be thoroughly burnt so that they become hard and durable.
Satisfactory burning of bricks is ascertained by a hard ringing soumd emitted when two
bricks are struck together. The bricks should be free from cracks, chips, and large particles
of
ime. The strength of brick masonry
chiefly depends
upon: () quality of bricks, ü)
yof mortar_and (iüi) method of bonding used. Unbonded wall, even constructed
WIthgood quality bricks and good quality mortar has little strength and stability.
Brick masonry is sometimes preferred over other types of masonry due to the
following reasons
.
n
All the bricks are of uniform size and shape, and hence they can be laid
any definite
pattern.
4. Brick units are light in weight and small in size. Hence these can be easily
handled by brick layers by
.
hand.
Bricks do not need any
dressing&
4The.art of brick laying can be understood very easily, and even unskilled
masons
Mas
masons.
can do the brick masonry. Stone masonry construction requires highly skilled
(167)
BUILDING CONSTRUCTIO
168
unlike stones which are availahla
Bricks are easily available at all sites,
do not require transportation from long distoy
at quarry sites. Due to this, they
done with bricks.
6 Ornamental work can be easily can be
easily constructed in brick mae
7.
partition walls and filler walls
5
distances,
masonry.
Light
6.2. TYPES OF BRICKS
7
Bricks used in_masonry can _be of two types
u
Traditional.bricks.
Modular bricks.
Traditional bricks are thosewhich have not been standardizéd in size. The dimensions
nsions
of traditional bricks vary from place to place. Their length varies trom 20 to 25 C
Cm,
width varies from 10 to 13 cm and thickness varies from 5 cm to 1.5 cm. The common
adopted nominal size of traditional brick is 23 cmx 11.4 cm * 7.6 cm (9"x43
a
proximately.
Modular bricks. conform to the size laid down by Bureau of Indian Standard
Institution, India. Any brick which is of the same uniform size as laid down by B+S
is known as the modular brick. The nominal size of the modularbrick is
20 cmx 10 cmx 10 cm while the actual size of the brick is 19 cm x 9 cm x 9 cm Nominal
sizeincludes the mortar thickness.Masonry modular bricks are economical to manufacture
require less area for drying, and staking, and requires less brick work for the same
surface area of the wall, in comparison to conventional bricks. The masonry with modular
bricks thus workout to be cheaper.
Classes of bricks
Quality wise, masonry
bricks are classified into three
bricks (ü)
Second class bricks and (iii)
Third class bricks.
() First class bricks.
First class bricks are those
which strictly conform to
the
classes: () First class
(a) Single bull nose
(b) Double bull nose
() Cow nose
standard size of modular bricks,
i.e.. 19 cm
9 cm x 9 cm actual
size, such that ten layersof
x
(d) Curved
(e) Coping brick
() Bird's mouth
brick laid in mortar will form
masonry of 1 metre height. Good
bricks are manufactured from
good quality plastic earth which
is free from saline
deposits.
They are of good uniform colaur.
They are well burnt: hard ring
ing sound is emitted when twwo
bricks are struck together. They
have straight edges and even
surfaces.They arefree from
cracks,chips,flawsand nodules
of lime. When Immersed in
(g) Cant
(h) Double cant
)Plinth stretcher
(k) Plinth header
(Splaystretcher)
(i) Squint
() Dog leg
(splay header)
FIG/6.1. SPECLALLY-SHAPED BRICKS
MASONRY-2: BRICk MASONRY
for
169
hour, they do not absorb water more than
one-sixth of their weign
wing,
they
do not show any sign of
n
(ii) Second class bricks. Second classafilorescence
bricks also conform to the standard
at they are slightl, irregular in
but
S17
and colour. They are also
shape
burnt,
fully
sound
ringing
1s emited when two bricks are struck together. When immersedana
in
wat
ater for one hour, they do not absorb water more
than
er
one
one-fourth of their weight.
(jii) Third class bricks. These are the
one which are
quite irregular in ther
size, shape and finish. They are not burnt
due
to
fully,
which they are of reddish-yellow
colour. These bricks have low
Moulded
crushing strength. They are not used for quality brick-masonry.
are those which are
manufactured in specjal
used for giving
architectural shapes. Such bricks are
used 1or
courses, sloping walls etc.
6.1
bricks. Moulded bricks
shapes and sizes to be
copings, cornices, string
specially-shaped bricks.
Fig.
shows
some
commonly
used
6.3. SOME DEFINITIONS
1.
Stretcher.
A stretcher is the
longer face of the brick (i.e. 19 cm x 9 cm) as
seen in the elevation of the wall. A course of
bricks in which all the bricks are laid
as stretchers on facing is known as a
stretcher course or
course.
2. Header. A header is
the shorter face of the brick
stretching
Quoin
ie. 9 cm x 9 cm) as seen in the
elevation of the wall. A' course
of bricks in which all the bricks
are laid as headers on the facing
is known as header course or
heading course.
3. Lap. Lap is the hori
zontal distance between the vertical joints of successive brick
courses.
4. Perpend. A perpend
15
an imaginary vertical
which includes the
line
vertical joint
separating two adjoining bricks.
Perpend
Racking
back
Quoin headers||
T
Stretcher course
Header course
Quoin closer
Vertcal joint
5. Bed. Bed is the lower
surface (19 cm x 9 cm) of the
brick when laid flat.
Toothing
Stretcher course
FIG. 6.2. ELEVATION OF A BRICK WALL.
6. Closer. It is a portion of a brick with the cut made longitudinally, and is
used to close up bond at the end of the course. A closer helps in preventing the
1 . s of successive sources (higher or lower) to come in a
vertical line. Closers may
be
of various types, defined below.
1. Queen-closer. It is a portion of a brick obtained by cutting a brick lengthwise
W o portions (Fig. 6.3 6). Thus, a queen- closer 1s a brick which is half as wide
as the full brick. This is also known as queen-closer-half When a queen-closer is broken
ato two pieces, it is known as queen-closer-quarter. Such a closer is thus a brick
plece which is one-quarter of the brick size (Fig. 6.3 c).
BUILDING CONSTRUCTION
170
of
8. King closer. It is the portion of a brick which is so cut that theis wid
equal
one
of
its end is half that
full
to the
centre
the
width
of
(Fig.
one
obtained by
It
6.3 d). It is thus
other (lay) side.
the centre of the
Bevelld
closer. It is a special form
of a king closer in which
the
whole length
length of
of th
the
whole
the
brick (ie..
has half-header
and
sd, metal
pice
a
Cdgeb
uC
tA
u te f i g d g .
K
------**
stretcher face)
is bevelled in such a way
that half width is
between
end and
half-stretcher face.
9.
a
at the other end
while the width
brick,
full
cutting the triangular piece
(a) Full brick
(b) Queen
closer(Half)
(c) Queen- doser (Quanter)
main
tained at one end and full
width is maintained at the
45° to 60
other end (Fig. 6.3 e).
10. Mitred closer.
It is a portion
of a brick
whose one end is cut
splayed or mitred for full
(d) King closer
(c) Bevelled closer
(g) Half bat
(h) Three quarter bat
() Mitred closer
width. The angle of splay
may vary from 45° to 60°.
Thus, one longer face of
the mitred closer is of full
length of the brick while
the other longer face is
smaller in length (Fig. 6.3
.
11. Bat. It is the
) Bevelled bat
FIG. 6.3. VARIOUS FORMS OF BRICK PORTIONS.
portion of the brick cut across the width. Thus, a bat is smaller in length than the
full brick. If the length of the bat is equal to half the length of the original brick,
it is known as half bat (Fig. 6.3 g). A
three-quarter-bat (Fig. 6.3 h) is the one havin8
its length equal to three-quarters of the length of a full brick.
If a bat has its width
bevelled, it is known is bevelled bat (Fig. 6.3 i).
12. Arris._It is the edge of a brick.
13. Bull nose It is a special moulded brick with one
edge rounded (single bul
nose, Fig. 6.1 a) or with two edges rounded (double bull
nose, Fig. 6.1 b). These are used
in copings or in such positions where rounded
corners are
to sharp arises
14. Splays, These are special moulded bricks which are preferred
Splay stretcher {plinth stretcher) and splay header (plinth often used to form inplinu
header) are shown
F1
6.1 g) and k) respectively.
15. Dogleg or angle. It is also special form of moulded bricks (Fig. b.
which are used to ensure a satisfactory bond at
quoins which are at an angle oun
than
right angle. The
he angle and
than right
of the faces forming the
angle. These
ary according
lengths
dogleg vary
are
accor
to requirements.
preferred to mitred closer.
It 18 a corner or
16. Quoin.
the external angle on the face
side of a wall. Generaly
171
MASONRY-2: BRICKMASONRY
quoins
are
are
at
rght
angles.
But in
some cases, they
may be at angles
greater than
90° also.
17. Frog or kick. A frog is an indentation in the face of a brick to form a
brick is laid with
holdingthe mortar. When
frog is only on one face, that
key for
ehat face on the top. Sometimes, frogs are provided on both the faces. However, no
(as a rule) and
brick has two
are provided in wire-cut bricks. A
Goos
ahand-made brick has only one frog.
frogs
pressed
18. Racking back. It is the termination of a wall in a stepped fashion, a
shown in
Fig.
6.2.
19. Toothing.
It is the termination of the wall in such a fashion that each
bond if the wall
end projects, in order to
is continued horizontally at a later stage (Fig. 6.2).
provide adequate
alternate course at the
6.4. BONDS IN BRICK WORk
Bond is the interlacement of bricks, formed when they lay (or project beyona)
those immediately below or above them. It is the method of arranging the bricks in
courses so that individual units are tied together and the vertical joints of the successive
courses do not lie in same vertical line. Bond of various types are distinguished by
their elevation or face appearance. Bricks used in masonry are all of uniform size
will result.
Ifthey are not arranged (or bonded) properly, continuous vertical joints
An unbonded wal, with its continuous vertical joints has little strength and stability.
Bonds help in distributing the concentrated loads over a larger area. Since bricks are
is easily performed.
Small units, having uniform dimensions, the process of bonding
be observed:
should
rules
Rules for bonding For getting good bond, the following
1. The bricks should be of uniform size. The length of the brick should be twice
obtained. Good bond is not possible
its width plus one joint, so that uniform lap is
if lap is non-uniform.
2. The amount of
lap
should be minimum
4
brick
along
the
length of the
andbrick across the thickness of the wal
in special locations.
3. Use of brick bats should be discouraged, except
header should coincide with the
4. In alternate courses, the centre line of
below o r above it.
line of the stretcher, in the course
the same
should be
5.
The
vertical
centre
perpend.
used
should be used only in the facing; they should not be
joints in the
6. The stretchers
wall
alternate
along
courses
n the hearting. Hearting should be done in headers only.
7. It is
preferable to provide
every sixth
sides of the wall.
of
Types of bonds. Following are the types
1.
3.
Stretcher bond.
English bond.
5.
Facing bond.
7.
Brick on edge bond.
9
Raking bond.
11. Garden wall bond.
2.
4
6.
8
10.
course a s a
header course
provided
Header bond.
bonds
in brick
Flemish bond.
English cross bond.
Dutch bond.
Zigzag bond.
on
both the
work
BUILDING CONSTRUCTION
172
6.5. STRETCHER BOND
Stretcher bond or
stretching bond is the
one in which all the
bricks are laid as
stretchers on the faces
2
of walls. The length of
the bricks are thus
along the directionof
the wall. This pattern
(b) Elevation
(a) Isometric view
is used only for those
walls which have thickness of half brick (i.e.
9 cm), such as those
used as partition walls,
Diok
sleeper walls, division
walls or chimney
stacks. The bond is not
possible if the thick-
2, 4, 6-- -courses
1,3,5- -Courses
(c) Plan
(d) Plan
FIG. 6.4. STRETCHER BOND.
ness of the wall is
more.
6.6. HEADER BOND
Header bond or heading bond is
the one in which all the bricks are laid as
headers on the faces of walls. The width
of the brick are thus
along the direction
of the wall. The
pattern
is used only when the
thickness of the wall is
equal to one brick (i.e..
4
18 cm). The overlap is usu3
ally kept equal to half the
width of brick (i.e. 4 cm).
This is achieved by using
2
I
1
AtBat
A
(a) Isometric view
three-quarter brick bats in
(b) Elevation
each alternate courses as
quoins. This bond does not
have strength to transmit
pressure in the direction
of the length of the wall.
As such, it is unsuitable
for load bearing walls.
However, the bond is specially useful for curved
brick work where the
stretchers, if used, would
project beyond
the face of
TILIID
Bats
4
2,4,6 courses
(c) Plan
Bat
1,3,6-- -courses
FIG. 6.5. HEADER BOND
(d) Plan
MASONRY-2:BRICK MASONRY
173
the wall and would necessitate inconvenient cutting, This is also used in construcuon
of footings.
6.7. ENGLISH BOND
This is the most commonly used bond, for all wall thicknesses. This Dona
considered to be the
strongest. The bond
con-
sists of alternate
courses
and stretchers.
of headers
In this bond, the vertical
jointa
of the
header
Q
10
HHHHTTTAA
9 S S
8 HE
6 HE
other; sinmilarly, the ver
5 Ss
tical joints of the stretcher
4HE
courses also come overr
3 s
each other. In order to
2 H
break the vertical joints
in the successive courses,
s
course
Stretcher
course
|S
a
1 Ss
Header
S|s
LILEA
7 |s
courses come over each
T|HHHEH
I
S| s
sSs
S=Stretcher; H =Header; Q= Queen closer
it is essential to place
FIG. 6.6. ENGLISH BOND.
queen closer after the first
header (quoin header) in each heading course. Also, only headers are used for the
hearting of thicker walls. Fig. 6.6 shows the general elevation of the English bond.
Fig. 6.7 and 6.8 shows English bonds for walls of various thicknesses
Essential
Features. Following are the essential features of English bond.
1. Alternative courses will show either headers or stretehers in elevation.
2. Every alternate header comes centrally over the joint between two stretchers
in course below.
3. In the stretcher course, the stretchers have a min. lap of th their length
over headers.
4. There is no continuous vertical joint.
5. Walls of even multiple of half bricks (i.e. 1 brick thick wall, 2-bricks thick
wall, 3-bricks thick wall) present the same appearance on both faces. Thus a course
showing stretchers on the front face will also show stretchers on the back face.
6. Wall of odd multiple of half bricks (i.e. 1/ brick thick wall, 2 ; brick thick
wall etc.) will show stretchers on one face and headers on the other face
7. The hearting (middle portion) of each of the thicker walls consists entirely
of headers.
8. At least every alternate transverse joint is continuous from face to face.
9. A header course should never start with queen's closer, as it will get displaced.
he queen's closer should be placed just next to the quoin header. Queen's closers
are not required in stretcher courses.
10. Since the number of vertical joints in the header course are twice the number
of vertical joints in the stretcher course, the joint in the header course are made thinner
an
the joints
in
the
stretcher
course.
atTLDING cONSTRUCTION
174
Header
Stretcher course
course
Queens oloser (Q)
Stretcher
-Header course
s
course
I S S
1,3,5- -courses
(a) Plan for
2, 4, 6 - - COurses
1 brick thick wall
LS| SL
L
2,4,6--- COurses
1,3,5- -CoursesS
(b)
Plan for
1
brick thick wall
H
Q
S|S|S
1,3,5---COurses
o
2,4,6-- -courses
(c) Plan for 2 brick thick wall
B.
-B
HQ
H
1,3,5 -
- COurses
2, 4,8-- -cOurseS
(d) Plan for 2
briok thick wall
S STRETCHER FACING; H =HEADER FACING; Q = QUEENS CLOSER
B1 = QUARTER BAT (QUARTER QUEEN'S CLOSER
FIG. 6.7. ENGLISH BOND
MASONRY-2: BRICK MASONRY
175
End
LaSs|s|
1,3, 5
End
courses
2,4,6-
(a) Plan for
Coursess
1brickthick wall
-0-End
End
QTKQ s s
1,3,5-- - COurses
2, 4,6-- -courses
(b) Plan for 2 brick thick wall
B2 B3
B
Q
O
End
End
HH |
Is|s|s|s|
1.3.5-
2,4,6- -cOurses
courses
(c) Plan for 25 brick thick wall
Isl
End
Q
H
End
S
2,4, 6- cOurses
1,3,5-- coursees
(d)
S STRETCHER FACING
Plan for 3-brick thick wall
H
HEADER FACING;
= QUEENS CLOSER
B1 BAT; B2= BAT; Bs BAT
FIG. 6.8. ENGLISH BOND. (ALTERNATIVE ARRANGEMENTS)
6.8. FLEMISH BOND
In this type of bond, each course is comprised of alternate headers and stretchers.
Every alternate course starts with a header at the corner (i.e. quoin header). Quoin
closers are placed next to the quoin header in alternate courses to develop the face
ap. Every header is centrally supported over the stretcher below it.
Flemish bonds are of two types
)
Double flemish bond
(iü)
Single flemish bond.
BUILDING CONSTRUCTO
176
HL
10 HE-OI
bond
1. Double flemish
9S
LL
S
H
8 H-Q
7SL
6 H-O
In the double flemish
the
bond, each course presents
both in the
s a m e appearance
front face as well as in the
back face. Alternate headers
and stretcher are laid in each
course. Because of this, double
flemish bond presents better
appearance than English bond.
5SL
H
Ls
4 H-OL
2 HE-Q
N
HS H
S
H
I S I A s H_ S]
FIG. 6.9. DOUBLE FLEMISH BOND (ELEVATION
Fig. 6.9 shows the general elevation of flemish bond, for all the wall thicknesses. Fig.6.10
shows the double flemish
bond in plan, for walls of
various thicknesses.
features of double flemish bond
Special
s
H
1. Every course con-
sists of headersand
stretchers placed alter-
Q
s
IuA
1,3, 5-
nately.
2, 4,6---COurses
- COursesS
(a) Plan for one brick thick wal
2. The facing and
backing of the wall, in each
course, have the same ap-
B2
pearance.
3. Quoin closers are
used next to quoin headers
in every alternate course.
B
S
4. In walls having
thickness equal to odd mul-
H SL
B1,3,5--- cOurses
2,4, 6 -courses
(b) Plan for 1 brickthick wall
tiple of halfbricks, half bats
and three-quarter bats are
amply used.
5. For walls having
thickness equal to even
multiple of half bricks, no
bats are required. A header
or stretcher will come out
as header or stretcher on
H
S
Q
B
B
InA
H
S
1,3,5 - cOurses
the same course in front
2, 4,6--cOurses
(c) Plan for 2 brick thick wall
as well as back faces.
S
STRETCHER; H =HEADER
B2=HALF BAT
Q
QUEENS CLOSER
B3=BRICK B1 =QUARTER BAT
FIG. 6.10. DOUBLE FLEMISH BOND.
MASONRY
BRICK:
MASONRY
177
2. Single femish bond Single flemish bond is omprised of double flemish bond
facing and
and English bond backing and
in each course.
bond thus
th English bond and appearance of flemish bond.This
strength
of the
However,
this
strength of
English
hearting
uses
bond
the
can
be used forthose
walls
having thickness
is done with
at
least equal to 1
brick. Double flemish
facing
good quality expensive bricks.
bricks can
cheaperflemish
sed for backing and hearting. Fig. 6.11 shows the However,
plan of single
bond
od
for various thicknesses of the wall,
Q.
S
K S]
B
1,3,5 courses
2, 4,6
courses
(a) Plan for 1 brickthiek wal
SHsH
B2
1,3, 5-
courses
2,4,6
COurses
(b) Plan for 2 brick thick wall
S= stretcher; Q
Queen's closer
B2-HALF BAT; Bs-BRICK; B1=QUARTER BAT
FIG. 6.11. SINGLE FLEMISH BOND.
Comparison of English
Bond and Flemish Bond
1. English bond is stronger than flemish bond for walls thicker than 1
brick.
2. Flemish bond gives more pleasing appearance than the English bond.
3. Broken bricks can be used in the form of bats in Flemish bond. However,
more mortar is required.
4. Construction with Flemish bond requires greater skill in comparison to English
bond.
6.9. FACING BOND
This bond is used where bricks of different thickness are to be used in the facing
and backing of the wall. In this bond, a header course is provided after several stretcher
different in the facing and backing, the vertical
courses. Since the thickness of bricks are
is kept equal to the least common multiple
1stance between the successive header courses
and facing bricks. Thus, if the nominal thickness of facing
the
otDricks
of backing
thickness
is 10 cm and that of backing bricks 1scm, the header course is provided
BUILDING CONSTRUCTION
206
3. The thickness of wall should not be less than 1/6 of the storey heighe
4. For basement walls, the thickness should not be less than one-third the heieho
of retained soil above basement level, nor should it be less than the thickness of wa
at ground floor plus 10 cm.
5. Table 6.6 is applicable for walls built of bricks or concrete blocks, using li
lime
mortar (1:3), or cement mortar (1:6) or composite mortar (1:2:9).
6.27. TYPICAL STRUCTURES IN BRICK WORK
Following are the common structures constructed in brick-work:
1.
2.
Piers
Walls
3.
Footings
Buttresses
5.
Thresholds
Window sills
8.
7.
Corbels
9.
Jambs
3.
10.
11. Brickwork curved in plan
12.
13. Retaining walls and breast walls
Copings
Ornamental brick work
Brick nogging
14. Fire places and flues
15.
Chimneys
16. Arches
17.
Lintels
18. Cavity walls.
Out of these, walls, piers and footings have already been discussed in earlier
articles of this chapter. Fire places and flues, chimneys, arches, lintels and cavity walls
have been discussed in separate chapters.
6.28. BUTRESSES
Buttresses are
piers that are provided
to resist thrusts from
roof
trusses
or
strengthen main walls
or boundary walls.
Taey give lateral support to the main load
bearing walls. They
are usually in the form
of projections and are
1
Section
Section
(a) Splayed capping
(b) Tumbled in capping
FIG. 6.39. BUTTRESSES
usually completed
with cappings. Two forms of cappings: i) splayed capping, and (ii) tumbled-in-capping
are shown in Fig. 6.39.
Buttresses are usually designed to resist overturning moment due to lateral thrus
Their thickness is found in such a way that the resultant of the vertical and later
loads remain within the middle third of the section so that no tension is develo
Buttresses must be constructed along with the walls so that they are bonded to
wall course by course.
6.29. THRESHOLDS
mal
door
the extern
Threshold consists of the arrangement of one or more steps outside the
thresho
1wo TOrns of thresholds are shown in Fig. 6.40. Each step of
opening.
MASONRY-2: BRICKMASONRY
207
should be constructed
Door
with slight outward-
slope
so
that the rain
str
done in cement mortar.
It is preferable too use
some sort of hard finishing on the top ofeach
Stepsp
GL.SU
G.L.
Concrete
constructed at the last
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step. Thresholds are
building
Floor
Steps
con-
struction should be
stage of
Door
opening
water can be easily
drained off. The
Floor
opening
Wall
(b)
(a)
FIG. 6.40. THRESHOLDS.
con-
struction, when other construction activities have almost come to an end.
6.30. WINDOW SILLS
A sill provides a suitable finish to the window opening and it affords a protection
to the wall below. A great many external sills in modern buildings are constructed
of bricks laid on edge, or of roofing tiles, both of which harmonize well with brick
walling. Fig. 6.41 shows vertical section and part elevation of two type of sills
The following points should be kept in mind in constructing brick sills:
1. The sills of windows, on external walls, should be properly weathered (slope
1 in 6) to drain off rain water.
Reveal
The projection of sill, if any, should
Reveal|
Wood frame
not be less than 50 mm and should
be suitably throated.
2. Bricks for the sills should
Brick on
edge
be hard, well burnt and set in ce
ment motar.
3. The top surface of the brick
sills should be provided with suitable finish.
4. In sills made of tiles, tiles
Drip
(a) Brick on edge sill
w
are laid in cement mortar and in
two courses, breaking joint as in-
Wood jamb
Wood frame
dicated in elevation (Fig. 6.41 6).
The lower course of tiles should
be provided
with continuous nibs
Tiles
Tiles
which form a perfect drip, past
Joint Joint
which no dripping rain water can
find its way.
5. It is preferable to provide
damp proofing course below the
window sill so that moisture does
not enter inside the structure.
(b) Tile sill
FIG. 6.41. BRICK AND TILE SILLS.
BUILDING CONSTRUu
RUCTION
208
6.31. CORBELS
Corbels are constructed to provide bearing for floor beams, girders and jack
Brick corbels are constructed by projecting bricks of each course from a wallarche
corbel course should not
Each
Stone
project more than 5 cm
from the corbel below,
lintel
and the total projection
of the corbel should not
project more than the
thickness of the wall.
Headers are used to
e
walla
form each corbel course,
and they should break
joint with the course be- Section
Elevation
low. Bricks used for cor(a) Continuous corbels
bel construction should
be of good quality and
Section
Section
(b) Isolated corbels
FIG. 6.42. CORBELS.
superior workmanship
for its construction should be used.
Corbels can be either continuous or can be isolated. Fig. 6.42 (a) shows
two
of continuous corbel. Fig. 6.42 (b) shows an isolated
corbel.
6.32. COPINGS
furms
Copings are provided io
serve
as
a
protective coverings
top. Coping throws
to walls at its
the rain water clear off the wall.
Bull nose
brick
Chamfered Half round Saddle back Tile or stone
brick
brick
(b)
(c)
brick
Sometimes, special moulded
bricks are used for coping,
having
proper weathering and throating.
If copings are made of
regular
bricks, they are to be properly
shaped. Bricks used for coping
should be hard and strong
enough
to resist
weathering actions. The
(a)
joints in the coping should be
fewer. They should be
invariably
constructed to cement mortar.
Fig. 6.43 shows
633. JAMBS
Jambs
crecsing
FIG. 6.43. COPINGS.
some common
types of brick copings
the vertical sides of the
openings left in the walls to receive doo
windows, fire-places etc. These are
built cither square
through or with a reces A
square through jamb is used
when there is sheltered
only
weakness in joint between the frame
opening. Otherwise, any
and
the
brickwork will let the rain water
A recessed jamb is better
tn
because the projecting nib of brickwork
through which rain may otherwise be driven to
protects
the inside. Recessed jambs are lso
known as rebated jumbs. The recess
may be either on the inside of the jamb O the
are
MASONRY -2: BRICK MASONRY
Qutside.
If it 1s on
inside,
209
then
he frame which is set within it
from outside. If the recess is on the outside,
will be partly
concealed
(a) Square - through jamb
the whole of the frame will be
visible. A square through jamb may
its outside face in
have splay at
AAAAE
ILAHZ
which it is known as splayed jamb.
Jambs may be constructed either
in English bond or in Flemish bond.
T
LHA
The square jambs in brick work
HHAAR
(b) Splayed jamb
(c) Rebated jamb with outside recess
are constructed as stopped ends.
For construction of brick jambs
with proper bond to avoid con-
A
ANN
tinuous vertical joints, it is es-
INHLHL
sential to use bevelled bats and
(d) Rebated jamb with inside recess
king, queen or bevelled closers.
FIG. 6.44. VARIOUS FORMS OF JAMBS.
6.34. ORNAMENTAL BRICK wORK
Ornamental brick work can be obtained by the use of special types of bricks
(moulded bricks), mortars of different colours, mortar joints of different thickness and
different arrangement of bricks, so as to get pleasing appearance. Sometimes, bricks
LULIL
(c)
(a)
Y
(b)
(a)
(a) VERTICAL PANELS
(b) DIAGONAL PANEL
(c) QUOINS
ORNAMENTAL BRICK WORRK
FIG. 6.45. EXAMPLEs OF
BUILDING CONSTRUCTION
210
of different
thicknesses a r e
with sharp and
in
can be used
used to
give
architectural treatment.
appearance.
Even
present more pleasing
of the bricks is also important
suitable pattern. Texture
but smooth face bricks are preferred
angular faces
a
mad
brio
coloured
Machine
ka
ough
better appearance,
n
produce deep sh
joints
frequent.
dust storms a r e
is used only for
areas, where
ornamental brick work
The
appearance.
better
and thus give
stones produce a much better e
fect.
combination of bricks, tiles and
work. Sometimes, a
ornamental brick work.
of
Fig. 6.45 gives few examples
sandy
textured bricks
give
Recessed
more
CURVED IN PLAN
6.35. BRICK WORK
as in construction of chimnev
sometimes required, such
Brick work curved in plan is
built exactly in the same mann
work curved in plan is
Brick
etc.
flues
soak pits,
is 6 metres or less, all coursea
es
but where the inner radius
as for general brick work,
should be of headers
with bricks cut to ra-
dius. For large work,
specially
moulded
bricks should be used
in lieu of bricks cut
to radius. Standard
bricks, if used would
give very wide joints.
In case of unimportant
works such as lining
to soak pits and cess
pools, circular brick
works of inner radius
2, 4,6-- - coursesS
1,3, 5- Courses
FIG. 6.46. CIRCULAR BRICK WORK
(1-BRICK
WALL)
less than 6 m may be built like brick work straight on plan or to a curve exreeding
6 metre inner radius. These specifications also apply to brick work polygonal in plan.
be
Where water tightness is required, moulded bricks, or bricks cut to radius should
with
used. Where water tightness is not a major consideration, bricks may be laid
varying joints.
Fig.
6.46 shows the
plan of
alternate
plan. The shape of the brick work
can
courses
of
1
brick thick wall circular in
be maintained either
by
a
template
of thin
board of wood, or by using a trammel.
6.36. BRICK NOGGING
Brick nogging is the term used to denote brick work built up between woode
quarters or framing. Fig. 6.47 shows brick nogging. The uprights or posts are
mm x 120 mm in size, placed at a central distance of 1.50 metres apart. The horz0
members are ribs of planking (known as nogging member) 100 mm x 50 mm,
at 900 mm vertical distance apart. All the faces of the timber in contact with
150
ed
masonry is well-coated with boiling coaitar (two coats) and the faces of timber eaid
to view, on completion, is given three coats of specified paint. The bricks are
in the openings of the framework and are placed in such a way that equal projecuar
of timber are left on both the sides. Brick work is done in lime or cement mor
tions
MASONRY-2:BRICK MASONRY
211
Wire nails
for bonding
-Angles
Horizontal
cement
Plaster
or
lime
work
B
r
i
c
k
in
sides
both
plastered
m o r t a r
FIG. 6.47. BRICK N0GGING.
After the completion of brick work, the surfaces of brick work is kept thoroughly wetted
before plastering. Nails are deiven into the ledge of the timber frame work to give
a hold to the cementlime plaster with which both faces of the brick work is then
finished off, of a thickness to be flush with the faces of the posts. The plastering
is cured for three weeks. If the wooden members are of shorter width and the entire
exposed surface is to be plastered, a metal lath is fixed on both the sides of nogging
and the entire area is then plastered. This arrangement will check the plaster from
peeling off from the wooden members.
6.37. RETAINING WALLS AND BREAST WALLS
A retaining wall is a wall of increasing thickness, which is constructed to retain
artificial filling (mostly earth fill) to one side. A breast wall is similar to retaining
wall, but it is constructed to protect natural sloping ground from the cutting action
of weathering agents. Fig. 6.48 (a) shows a retaining wall and a breast wall in respective
positions. The method of designing both the walls is the same ; only the function
of each is different. The following salient points are note worthy:
1. Because of the increase of earth pressure with the depth of fill, the section
ot retaining wall/breast wall increases from top to bottom. Generally, the back of the
wall is stepped while the face is kept either vertical or inclined.
UILDING CONSTRUCTION
212
CTION
Cut
Fill
(a)
Breast wall
Retaining wall
Face
Weep hole
Back
Weep hole
G.L
(c)Retaining wall
(b) Breast wall
TNZZAZN
3
Plan at top
Section A\B
(d) Counterfort retaining wall
FIG. 6.48.
2. Breast walls are some times j.0ovided with batter on both sides, as shown
in Fig. 6.48 (6).
3. When the height of fill is large,
simple retaining walls become uneconomical.
In that case, lateral supports are
provided, on earth side, at regular interval
4 metres). Such a wall is known as
counterfort
as shown in Fig.
retaining wall,
b.*o
(d). The counterforts must be tied to the main wall with internal irou ties to counterac
any tendency to fräcture at the junction.
4. As a thumb rule, the thickness of wall at
any depth h below the fill leve
may be kept between 0.33 h to 0.4 h, depending upon the conditions of the nue
material.