Practical No. 11

Practical No.
11
IDENTIFY SUPERSTRUCTURE
CONSTRUCTION ACTIVITIES
AND THE EQUIPMENTS/ TOOLS
BRING USED AT PLASTERING
Introduction
 Plaster is a thin layer of mortar applied over the masonry surface and it acts as
a damp-proof coat over the brick masonry work. Plastering also provides a
finished surface over the masonry that is firm and smooth hence it enhances
the appearance of the building.
 The primary objectives of plastering are to protect the surface from
atmospheric influences, to cover the defective workmanship in masonry, to
conceal porous materials, and to provide a suitable surface for painting.
 Plastering work:
Procedure of Plastering Work
 Preparation of Surface for Plastering

 Keep all the mortar joints of wall rough, so as to give a good bonding to hold
plaster.
 Roughen the entire wall to be plastered.
 Clean all the joints and surfaces of the wall with a wire brush, there should be no
oil or grease etc. left on wall surface.
 If there exist any cavities or holes on the surface, then fill it in advance with
appropriate material.
 If the surface is smooth or the wall to be plastered is old one, then rake out the
mortar joint to a depth of at least 12 mm to give a better bonding to the plaster.
 Wash the mortar joints and entire wall to be plastered, and keep it wet for at least
6 hours before applying cement plaster.
 If the projection on the wall surface is more than 12 mm, then knock it off, so as
to obtain a uniform surface of wall. This will reduce the consumption of plaster.
 Groundwork for Plaster
 In order to get uniform thickness of plastering throughout the wall
surface, first fix dots on the wall. A dot means patch of plaster of
size 15 mm * 15 mm and having thickness of about 10 mm.
 Dots are fixed on the wall first horizontally and then vertically at a
distance of about 2 meters covering the entire wall surface.
 Check the verticality of dots, one over the other, by means of
plumb-bob.
 After fixing dots, the vertical strips of plaster, known as screeds,
are formed in between the dots. These screeds serve as the gauges
for maintaining even thickness of plastering being applied.
 Mixing of cement and sand for plastering work.
 Applying Under Coat or Base Coat
 In case of brick masonry the thickness of first coat plaster is in general
12 mm and in case of concrete masonry this thickness varies from 9 to
15 mm.
 The ratio of cement and sand for first coat plaster varies from 1:3 to
1:6.
 Apply the first coat of plaster between the spaces formed by the
screeds on the wall surface. This is done by means of trowel.
 Level the surface by means of flat wooden floats and wooden straight
edges.
 After leveling, left the first coat to set but not to dry and then roughen
it with a scratching tool to form a key to the second coat of plaster.
 Applying of base coat of plastering for brick masonry
 Applying Finishing Coat
 The thickness of second coat or finishing coat may vary between 2 to 3
mm.
 The ratio of cement and sand for second coat plaster varies from 1:4 to 1:6.
 Before applying the second coat, damp the first coat evenly.
 Apply the finishing coat with wooden floats to a true even surface and
using a steel trowel, give it a finishing touch.
 As far as possible, the finishing coat should be applied starting from top
towards bottom and completed in one operation to eliminate joining marks.
 Applying of Finishing coat of plastering work
 Curing of Plastering works
 After completion of the plastering work, it is kept wet by sprinkling water
for at least 7 days in order to develop strength and hardness.
 Use of gunny bags or other materials is used to keep the plastering works
wet in external works.
 Improper curing may lead to cracks formation or efflorescence in plaster
work.
 Care be taken after Completion of Plaster Work
 Cleaning of doors or frame and floor area is necessary at the completion of
work.
 Curing should be started as soon as the plaster has hardened sufficiently and
must be cured for at least 7 days.
 Curing shall commence, 24 hours after the plaster is laid.
Tools and Equipments Required for Plastering :
 Trowel
Lath Hammer
 Spatulas
 Hawk Hammer and Bolster
 Bucket and gauging trowels Kango Hammer Drill
 Internal/external angle trowel
Splash Brush
 Floats
 Harling Trowel Board and Stance
 Straight/feather Edge and Darby Mixing Wheel
 Scratch Comb
Mixing drill and paddle
 Spirit level
 Tin snips
Machine Plastering
Trowels
• Used to apply materials
• Different types and sizes

Spatulas
• Used to flatten plaster on walls
and ceilings
• Different types and sizes

Hawk
• Used for holding materials

Bucket and gauging trowels
• Both are used to mix, remove and clean materials from
buckets.
• Also can be used to plaster awkward areas.
Internal/external angle trowel
• Used to form a clean and sharp internal and
external angle
Floats
• Used to flatten and close-in surfaces
on internal backing/finishing coats
and external finishes.
Harling Trowel
Used for throwing dry and wet

dash onto a background.
Straight/feather Edge and Darby
• All are used to straighten and flatten

surfaces.
Scratch Comb
• Used to provide a mechanical key between coats
Spirit level
• Plasterers use them for making sure that angle
beads, walls and floors are plumb and level.
Tin snips
• Used by plasterer to cut metal trims and EML
Lath Hammer
• Used for stripping down old plaster.

• Trimming joint edges.
• Nailing plaster board.
• Withdrawing nails.
• Providing a key.
Hammer and Bolster
• Used for manually stripping down old
plaster.
Kango Hammer Drill
• Used for stripping down old internal and
external plaster/tile brick
Splash Brush
• Used for cleaning tools.
• Used for damping down walls.

• The best type is a good quality 5’’or
6’’decorators brush
• A good brush will retain its shape and

hold water.
Board and Stance
• Used for storing material ready to be applied.
• Make plaster easy to transfer on to the hawk .

Mixing Wheel
• For hand mixing of plaster
• Used for Mixing small batches of material.

Mixing drill and paddle
• This is a power tool that has a long stem with a
paddle on the bottom. It enables you to mix
plaster easily and thoroughly and at a
controlled speed.
Machine Plastering
• Increased Meterage
• Saves time
Thank You..

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Practical No.

 Preparation of Surface for Plastering

• Different types and sizes

• Different types and sizes

• Used for holding materials

Used for throwing dry and wet

• All are used to straighten and flatten

• Used for stripping down old plaster.

• Used for damping down walls.

• A good brush will retain its shape and

• Make plaster easy to transfer on to the hawk .

• Used for Mixing small batches of material.

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