What is Plaster?
Plaster is a building material used for coating walls and
ceilings. Sand-cement plaster is used extensively in building
work as a decorative or protective coating for concrete and
masonry walls .
Plaster is one of the oldest building materials, the most
primitive form was mud plaster, used to hold together
structures made of branches or wood for example. Today
internal plastering is used more as a way of smoothing out
surfaces and preparing them for decoration, it also adds
strength to the wall or ceiling and helps seal together building
Know your Materials!
Cement Sand Recron Fibre
Final Mortar mix (made from
mixing Cement,sand,water and
recron fibre) present in a Mudpan
1. After the masonry wall made of bricks or aerated blocks is ready, it is
first cleaned properly before starting the plastering wall using brushes
Brick wall Aerated Block wall
2. The scaffold is prepared for provide the labour a platform to stand and
materials required for plastering are transported at the site of plastering.
3. Cement Mortar is prepared by mixing cement and sand in ratio specified. For
ex-In our case the ratio specified is 1:4.So we use
1 unit volume of cement for 4 unit volume of
sand. The normal cement bag is 50 kg in mass
0.035 m3. So we prepare a container of volume
0.035 m3 and pour 4 containers of cement.
4. Recron fibre is added to it as it helps in avoiding cracks in plaster. We use 125
gm fibre for 1 bag of cement.
5. Water is added .As per as IS standards 0.025 m3 of water is added to 1 bag of
cement, but at site it is subjected to the workability requirements.
Note: The mortar mix should be used within it’s initial setting time = 45 min
6. Chicken mesh is used at the joint of Lintel and masonry wall to avoid cracks at
the joint in future.
Chicken Mesh Labour putting Chicken Mesh
7. Making of Level Pads : Level pads are used for maintaining the thickness of
plaster coat required.They act as a reference for checking thickness of plaster.
- First we lay a reference line using rope and nails
- We check the distance of wall from this reference line and note it(say D1)
- Now we put the mortar of wall and smoothen it. We now calculate the
distance between the reference line and level pad’s surface(say D2)
D1-D2= Thickness of coat required
- If the thickness doesn’t matches then adjust the thickness of level pad
- Now make one level pad above the first level pad and check if it’s in line
with the help of plumb bob.It might happen the wall is not exactly vertical
either inwards or outwards which can be checked with help of plumb bob
hence thickness of level pad can be adjusted accordingly.
Labourers checking the distance of wall from reference
Making of level pad
Labourers checking distance of level pad from reference
No gap between wall and plumb
bob, signifying that wall is straight
Gap between wall and plumb
bob indicating that wall is
- After checking for vertical alignment of level pads, check for horizontal
alignment with the help of a rope( pin a rope parallel to the first level pad
also vertical with adjacent wall).Adjust the level pads in thickness if the wall
is tilted sideways.
Checking for vertical alignment of pads
Horizontally laid level pads
8. After making the level pads, wet the wall with help of diluted cement water slurry
to provide better adhesion with mortar.
9. The mason then applies the mortar on the walls
with the help of trowel.
10. With the help of metal float the mason creates a smooth reference plain of
required thickness by pressing the float against two vertical level pads.The
additional mortar is scrapped of with the help of float.
11. The finishing of the plaster is done with the help of finishing trowel.
Removing excess material with
12. After smoothening, the plaster is roughened up for providing better adhesion in
case of a second coat. A hair is used for it or sometimes labour also uses chicken
Hair used for roughening
Rough Plaster coat
Challenges in Manual Plastering
1. A proper hierarchical system is not present on site. Ideally the engineer should
teach the supervisor as in what he requires and the supervisor should convey it to
the labour.But due to lack of number and agility of supervisors the engineer has
to do that part.
2. Due to above point, the engineer is not able to perform his main task efficiently
which is Quality Checks .Two examples in this regard are:-
(a) Amount of water is not as per as standards and the labour puts water
according to his will. This in turn degrades the quality of the mix.
(b) Checking of the thickness and alignment of level pads is not proper which
leads to lack of uniformity of plaster. Plumb checking is not also proper.
3. The mortar is not used within it’s initial setting time of 45 Minutes and sometimes
used beyond 4 hours. This again degrades the quality.
4. The floor is not cleaned properly before starting plaster and sacks are not always
laid down to collect the fallen mortar. So the mortar gets mixed with the mud and
is then used again which has serious implications on the quality.
5. Due to lack of supervision the labour is idle for a lot of time.Also due to the fear of
loosing labour the supervisor also doesn’t say much to them as his performance is
judged by the way he handles the labourers.This leads to slow pace of work.
Fallen Mortar getting mixed