Plastering - Complete Guide

Definition:
  • Plastering is the process of providing a coat of mortar on masonry or concrete surfaces for aesthetic purpose.
  • It gives even regular surface on which decorative finishes can be further applied.
  • Externally, plastering acts as a protective coating against weathering agents like rain, sun, frost, etc. 
Slapping mortar with Plastering Trowel
                                 
Tools Required:
  1. Trowel (Karni)
  2. Aluminium Straight Edge (Funty)
  3. Finishing Board (Russa)
  4. Sponge
  5. Spirit Level
  6. Right Angle
  7. Nylon Thread (Line Dori)
  8. Mixing Tray
  9. Measurement Box or Farma Box 
  10. Mortar Pan (Thasla)
  11. Spade (Powda / Kassi / Mamti)
  12. Water Buckets or Drum
Technical Data:
Thickness Ratio
Internal Plaster - Ceiling 
  12mm  1:4
Internal Plaster - Wall
  15mm  1:6
External Plaster - Rough Coat  12mm  1:6
External Plaster - Final Coat   8mm  1:4

Execution Method:

  1. Mortar mixed for the required ratio (Mortar once mixed should be consumed within 45 minutes)
  2. The surface to be plastered is made wet by spraying the water
  3. And then cement slurry (Gola) coat of 1:1 is made and splattered on the surface
  4. Mortar slapped on the entire wall with trowel
  5. With aluminium straight edge mortar is leveled with respect to the button/bull mark
  6. With wooden finishing plate final finishing is achieved. (Sponge is used in case of rough finish)
  7. Water resistant additive (eg:Cera Latex SBR) is mixed in final coat of external plaster
Material Requirements:
  • Cement
    • Air Permeability Test
    • Compressive Strength Test
    • Fineness Test
    • Setting Time Test
    • Soundness Test
    • Standard consistency test    
  • Sand
    • Sieve Analysis should be Fine Sand  (If it is coarse sand or medium sand then sand should be sieved with sand sieving machines or sieving tray)
    • Silt Content should be less than 7%
Material Consumption Calculations:
      Example: Wall size : 3m x 3m
      Ratio 1:6 & Thickness 15mm
      Cement Requirement 
      Sand Requirement

      Note 1: Cement density is 1440 kg/m3 and Sand Density is 1600 kg/m3
      Note 2: 1.25 is factor for increasing the cement and sand by 25% due to uneveness in the wall
      Note 3:   Another 1.25 is the factor for increasing the mortar by 25% due to volume of wet mortar decreases by 25% of dry mortar when we add water because of voids in sand.

Pre - Execution Checks:
Hacking in Beam and Mesh fixing on beam - block work joint
  1. Hacking need to be done in all concrete surfaces for better bond
  2. Mesh fixing need to be done wherever block work and concrete interface is there to avoid crack       
  3. Bull fixing need to be carried out perfectly with taken care of perfect right angle and perfect spirit level.
    During Bull Fixing - Usage of Right Angle
    During Bull Fixing - Usage of Spirit Level
  4. Corner beads need to be fixed wherever exposed corners are there to avoid breaking of corners
Post Execution Checks:
  1. Curing need to be done minimum of 7days
  2. Right angle and spirit level need to ensured before starting the next activity

Testimonials