What is pointing? Scope of pointing Method of pointing What is plastering? Objective of plastering Lime plaster Cement plaster Gypsum plaster (plaster of Paris) Water proof plaster of Mortar Heat resistant plasters Defects in plastering 1.Stretcher bond 2.Header bond 3.English bond and 4.Flemish bond.

3. What is pointing?
• It is the art of finishing the mortar joints in
exposed brick or stone masonry with suitable
cement or lime mortar, in order to protect
the joints from weather effects and also to
improve the appearance of building structure.
• Often an entire wall, or even a whole
structure, is pointed because defective points
cannot easily be detected, and adjacent joints
may also be in need of repair. The mortar is
packed tightly in thin layers and tooled to a
smooth, concave, finished surface.

4. Scope of pointing
• Maintaining the joints of the structures.
• Pointing being cheap can be adopted in places
of low rainfall.
• Where the natural beauty of materials, viz.,
stone blocks, bricks etc, is desired to be
exhibited.
• Gives resisting power to the bricks and stones
used in construction towards weather
conditions.

5. Method of pointing
• All the mortar joints (on the masonry face required to be
pointed) are raked out by a special pointing tool to a depth
of 15 to 20 mm, so as to provide an adequate key for the
fresh mortar used for pointing.
• All the loose mortar and dust are removed by brushes
• The joints and wall surface are washed with clean water,
and then kept wet for few hours.
• The joints so prepared, are filled with suitable mortar with
a small trowel. The mortar is well pressed into the joints to
form a close contact with the old interior mortar joints. All
excess mortar sticking to the sides is scraped away.
• The finished pointing work is kept wet for about 3 days
when lime mortar is used for pointing and for 10 days
when cement mortar is used for pointing.

7. What is plastering?
• Plastering is the process of covering rough walls and
uneven surfaces in the construction of houses and
other structures with a plastic material, called plaster
or mortar.
Objective of plastering
• To provide an even, smooth, regular, clean and
durable finished surface with improved appearance.
• To preserve and protect the surface.
• To cover up the use of inferior quality and porous
materials of the masonry work.
• To conceal defective workmanship.

8. Requirement of the good
plaster
• It should be hard and durable.
• It should be possible to apply it during all weather
conditions.
• It should adhere to the background and should remain
adhered during all climatic changes.
• It should be cheap and economical.
• It should offer good insulation against sound and high
resistance against fire.
• It should effectively check the entry or penetration of
moisture from the surfaces.

9. Method of plastering
(general)
• The plaster may be applied in one or more coats, but the
thickness of a single coat should not exceed 12 mm.
• In the case of inferior or cheaper type of construction,
the plaster may usually be one coat. For ordinary type of
construction, the plaster is usually applied in two coats,
whereas for superior type of works it is applied in three
coats.
• The final setting coat should not be applied until the
previous coat is almost dry.
• The previous surface should be scratched or roughened
before applying the next coat of plaster.
• In plastering, the plaster mix is either applied by
throwing it with great force against the walls or by
pressing it on the surface.

10. Types of plasters
• Lime plaster
 Lime plaster is a mixture of calcium hydroxide and sand
(or other inert fillers) in 1: 1 ratio.
 Carbon dioxide in the atmosphere causes the plaster to
set by transforming the calcium hydroxide into calcium
carbonate (limestone).
 In order to improve building properties of lime plaster ,
gugal (a kind of fragrant gum) @ 1.6 kg/m3 of mortar , is
added when the mortar is being ground.
 In order to improve adhesive and tensile properties of
lime mortar, sometimes, small quantities of chopped
hemp (i.e., vegetable fibres) @ 1kg/m3 are added to the
lime mortar.
 The lime mortar thus prepared is usually kept for 2 days
before use.

11. • Cement plaster:
 Cement and sand in required proportions ( 1:3 or 4) are first
thoroughly mixed in dry conditions and then water is added to
form a paste of required consistency.
 Generally it is mixture sand, portland cement and water mixed in a
suitable proportion.
 This prepared mortar for plastering should be consumed within 30
minutes after the addition of water.
• Gypsum plaster (plaster of Paris)
 Gypsum plaster, or plaster of Paris, is produced by heating
gypsum to about 300 °F (150 °C).
2CaSO4·H2O + Heat → 2CaSO4·½H2O + H2O (released as steam)
 When the dry plaster powder is mixed with water, it re-forms
into gypsum. The setting of unmodified plaster starts about
10 minutes after mixing and is complete in about 45 minutes
but not fully set for 72 hours.

12. • Water proof plaster of Mortar:
 This mortar consists of 1 part of cement, 2 parts of sand and
pulverised alum @ 12 kg/m3 of sand. To this dry mix , the soap
water containing about 75 g of soft soap/L of water , is added to
obtain the waterproof mortar.
• Heat resistant plasters
 It's purpose is to replace conventional gypsum plasters in cases
where the temperature can get too high for gypsum plaster to
stay on the wall.
 Heat resistant plaster should be used in cases where the wall is
likely to exceed temperatures of 50°C .
 Heat resistant plaster is a building material used for coating
walls and chimney breasts.

13. Defects in plastering
The following defects may arise in the plaster work:
 Blistering of plastered surface: This is the
formation of small patches of plaster swelling out
beyond the plastered surface, arising out of late
slaking of lime particles in the plaster.
 Cracking: it is the formation of cracks in the plaster
work due to the following reasons:
 Structural defects in building
 Movements in the background due to its thermal
expansion or rapid drying
 Movements in the plaster surface itself, either due
to expansion or shrinkage.

14. • Efflorescence: It is the whitish crystalline substance which
appears on the surface due to presence of salts in plaster
making materials. It affects the adhesion of paint with wall
surface. Efflorescence can be removed to some extent by
dry brushing and washing the surface repeatedly.
• Flaking: It is the formation of very loose mass of plastered
surface, due to poor bond between successive coats.
• Peeling: It is the complete dislocation of some portion of
plastered surface, resulting in the formation of a patch. This
also results from imperfect bond.
• Popping: It is the formation of conical hole in the plastered
surface due to presence of some particles which expand on
setting.

16. Brick masonry
 Brick masonry is built with bricks bonded
together with mortar. For temporary sheds mud
mortar may be used but for all permanent
buildings lime or cement mortars are used.
 The various types of bonds generally used in
brick masonry are:
1. Stretcher bond
2. Header bond
3. English bond and
4. Flemish bond.

17. Stretcher bond
• A stretcher is the longer face of the brick as seen
in the elevation. In the brick of size 190 mm ×
90 mm × 90 mm, 190 mm × 90 mm face is the
stretcher. In stretcher bond masonry all the
bricks are arranged in stretcher courses.
• However care
should be taken to
break vertical
joints. This type of
construction is
useful for the
construction half
brick thick
partition wall.

18. 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. This type of bond is useful for the
construction of one brick thick walls.

19. English bond
• In this alternate courses consist of headers and
stretchers. This is considered to be the strongest
bond. Hence it is commonly used bond for the
walls of all thicknesses. To break continuity of
vertical joints a brick is cut lengthwise into two
halves and used in the beginning and end of a wall
after first header. This is called queen closer.
Figure shows typical one brick and one and half
brick thick wall with English bond.

21. Flemish bond
• In this type of bond each course comprises of alternate header
and stretcher figure. Alternate courses start with stretcher and
header. To break the vertical joints queen closers are required, if
a course starts with header. Every header is centrally supported on
the stretcher below it.
• Flemish bonds may be further classified as:
I. Double Flemish Bond
II. Single Flemish Bond.
• In case of double flemish bond, both faces of the wall have
flemish look, i.e. each course consist of alternate header and
stretcher, whereas single flemish bond outer faces of walls have
flemish look whereas inner faces have look of English bond [Fig
(a), (b)].
• Construction of flemish bond needs greater skill. It gives more
pleasing appearance. But it is not as strong as English bond. If
only pointing is to be used for finished wall, flemish bond may be
used to get good aesthetic view. If plastering is going to be used, it
is better to use English bond.

23. Advantages and Disadvantages of
Brick Masonry Over Stone Masonry
Advantages:
1. Since shape and size of bricks are uniform, it do not need skilled labour
for the construction.
2. Bricks are light in weight and hence handling them is easy.
3. Bricks are easily available around cities and their transportation cost is
less because their weight is less. Stones are to be brought from quarries
which are located only at few places.
4. It is possible to use all types of mortar in brick masonry. For
unimportant buildings even mud mortar can be used.
5. Thinner walls can be constructed with bricks but it is not so with stones.
6. It is easy to form openings for doors and windows.
7. Dead load of brick masonry is less.
8. In brick masonry mortar joints are thin and hence construction cost is
reduced considerably.
9. Brick masonry has better fire and weather resistance compared to
stone masonry.

24. Disadvantages:
1. Strength of brick masonry is less than that of stone masonry.
2. Durability of brick masonry is less.
3. Brick masonry needs plastering and plastered surface needs
colour washing. Stone masonry don’t need them and hence
maintenance cost is more in brick masonry.
4. Brick masonry absorbs water and there are possibility of
dampness. There is no such problem in stone masonry.
5. More architectural effects can be given in stone masonry
compared to that in brick masonry.
6. Stone masonry gives massive appearance and hence monumental
buildings are built in stone masonry.

26. Some points
• Reinforcement masonry
does not require
expensive element of
concreting.
• Reinforcement masonry is
capable of taking tensile
and shear loads.
• Reinforcement masonry is
a cheap, durable, fire
proof and easy to
construct.
• Reinforcement masonry is
used for construction of
walls, columns, lintels and
slabs.

29. Important points
• Concrete Association of India recommends face
thickness should be less than 5 cm and net area
should be minimum of 55 to 60% of the gross area.
• The holes in the block should be at least two in
number and they should preferably be oval shaped.
• The common sizes generally adopted for building
blocks are: 39x 19x 30 cm; 39x19x20 cm and
39x19x10 cm.
• The blocks are manufactured by using the mixture of
fine aggregates 60% and 6 to 12 mm size coarse
aggregate 40%. The fine modulus of the mixture
should range between 2.9 to 3.6. The 1:6 (cement to
combined aggregate) concrete mix should be used.
• The strength of block should be 30 kg/cm2

30. • For the construction of walls, only well dried blocks
should be used. Blocks should have less than 10% water
absorption for external walls and less than 15% for
internal walls. Blocks with higher water absorption should
be painted with water proof material.
• The joints should be 5 mm to 10 mm in thickness and
cement, lime and sand mortar of 1:1: 10 should be used.
• When two walls of different heights meet each other, they
should be separated by a joint.
• In order to avoid cracks , hollow blocks filled with
concrete should be used at the junction of walls.
• When used in columns, the hollows within the blocks
may be filled with concrete.
• Lintels should be made of hollow channel-shaped blocks
filled with concrete having steel reinforcement at their
bottom.

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