Comparison Between Gypsum Plaster and Cement Plaster

Houses are externally and internally plastered to overcome deviation in plumb and line that are inherently occurred due to deviations in RCC and masonry wall, line and level individually. Also, there are numbers of joints in individual masonry courses and between RCC and masonry wall. These joints are prone to rain water ingress. External plaster (Waterproofed) becomes a necessity to give watertight envelope to a building.

External plaster is usually done in double coat as arrived thickness is < 20mm. Internal plaster is usually done in single coat as arrived thickness is 12 – 15 mm. If thickness of plaster is more than 15mm then double coat of internal plaster is recommended.

A wall is plastered to a finish ready to receive paint coats on it. A good plaster surface is necessary for a satisfactory paint finish. Any imperfections in plastered surfaces get reflected after a paint finish which can be an eyesore.

Plaster are basically done using Cement Mortar and/or Gypsum. Here we will discuss in detail the comparison between both these kinds of plaster i.e. Cement Plaster and Gypsum Plaster.

Technical comparison between Cement Plaster and gypsum Plaster

Parameters Cement plaster Gypsum plaster
Basic Raw Material ·         Cement + sand (Site mixed) ·         Cement + sand (Packaged) Gypsum powder
Manufacturing Site –  Site mixed Factory – Ready Made Packages Factory made
Green Product NO YES
Application areas Internal & External Internal (Non- wet areas, excluding kitchen,bathrooms,balconies etc)
Standard packaging size 40 kg 25 kg
Consumption per (12mm thick plaster) ·         For 1: 4, Cement = 39 kg Sand = 4 cft covering 100 sq.ft. area ·         40 kg bag – 16 to 18 sq.ft. 25 kg bag – 18 to 21 sq.ft
Compressive strength 3.5 to 7.5 MPa (depending on ratio) Example: 1:4 –  4 to 5 MPa 5 – 7 Mpa
Minimum coat thickness  > 10 mm Should not be Less than 10 mm < 6 mm Should Be building more than 6mm or else will peel off
Finish
  • Depend on quality of sand
  • May require POP Punning (6-8 mm) on it
Smooth finish and Ready to receive paint built up
Curing Wet curing for 07 days Air curing for 24 hrs.
Disadvantage Prone to plastic/drying shrinkage cracks Need to avoid prolong dampness
Recommendations External plaster All wet internal areas (kitchen, Toilet & Terraces/Balcony). Internal walls and ceiling (Non wet area)
 Cost Per 100 Sq ft  Rs. 2,000/- Rs. 2600/-, If POP punning is done to prepare a smooth surface  Rs. 2,300/-

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