Estimation of Plastering
Estimation of Plastering having comprehensive Terminologies and Details
This article comprises the complete estimation of Plastering by considering one small civil Engineering structure. For the estimation of Civil Engineering projects, it is necessary to consider every aspect which can be a part of the final rate analysis. Plastering Activity has a major role in the cost of construction projects. In this article, we will be calculating plastering material (cement sand and water)
Before estimating the material for Plastering let’s recall the history of Plastering work, discuss comprehensive terminologies, and standard thickness for plastering.
History of Plastering work
When we recall the history of plastering, it came to know that plastering is not the current activity it has been considering for centuries. As long as (7500 BC) it was the prehistoric era when it discovered. Some people in Jordan discovered the concept of Plastering. By discovering lime based plastering material they used it in flooring interior and exterior walls. Although, the method of plastering was different. They did not use trowel rather they used sticks and reeds for the construction of houses and they covered them with mud thick layer and called it plaster.
Egyptian Era of Plastering
During the era of Egyptians, some notable people did advancements in materials for plastering but the tools for plastering work were the same as they were in the prehistoric era. They discovered a binding mixture of lime and gypsum then used it to cover their pyramids and other masonry structures. the plastering on the pyramid is as solid today as it was provided.
Roman Era of Plastering
These were people who discovered advanced plastering material and tools. They discovered it by mixing the stucco with lime and sand then used for plastering purposes for their buildings. Apart from this, for aesthetic purposes, they used to provide fine layer of plaster on structures. They prepared it by mixing many constituents (gypsum, lime, and dust)
In the Middle Ages,
people started to use gypsum as a major constituent for plastering. It is a basic component that keeps the binding properties. Although they also used some admixtures to change the elastic properties of plaster
Purpose of Plastering
Plastering is a binding material used for covering interior walls, exterior walls, and other structural components for aesthetic purposes.
There is a difference between plastering and Rendering. Plastering refers to the application of material for internal purposes and rendering refers to the application of material for exterior purposes.
Purpose of Plastering
When we construct a structure, some uneven and rough surfaces expose, so the purpose of plastering is to cover these surfaces. it is a mixture of sand cement and water having a standard proportion.
Types of Plastering
There are many types of plastering. Some important types are mentioned below;
When we use cement as a binding material then it is called cement plaster. It is generally used for moist condition
- i ) -The thickness of cement plaster varies from 12mm to 15mm.
- ii ) – It depends upon the construction site and purpose of the structure.
- iii ) – For reinforced concrete structures 6mm thickness is usually preferred having 1:3 or 1:4 (cement: sand)
Stucco is the plaster but somehow more decorative than normal plaster, stucco plaster Gives very smooth and excellent finish
- Stucco plaster is used for both interior and exterior surfaces
- It has usually three layers and the total thickness of stucco plaster is 25mm
Mud plaster is the same as cement plaster but mud is used as a binding agent
Instead of cement.
- It has two coats having different thickness
- The thickness of the first layer is 18mm
- The thickness of the 2nd layer is 6mm
The standard thickness of Plaster
- The thickness of plaster for single coat = 12mm
- The thickness of plaster for double coat = 12mm (first coat) and 8mm (2nd coat)
- Apart from this, standard thickness for brick walls are 12mm, 15mm and 20mm
Standard cement sand ratio
the cement-sand ratio for inner plastering is commonly used 1:6 (cement: sand). While on the other hand for outer plastering ratio is increased up to 1:4 (cement: sand)
let’s calculate the plastering materials (cement, sand, and water) for a small civil engineering structure.
Estimation of Plastering
Inside we are applying two coats of plastering so that’s why we multiplied the above factors with the digit “2” while outside we are applying only one coat.
Total area of plastering= 4650 square feet
Standard thickness of plastering on wall = 12mm = 0.03936 feet
Total volume of plastering = total area thickness = 4650 0.03936 = 163.024 cubic feet
Standard (cement: sand) = 1:4
as we know wet volume of mortar is less than then dry volume because as we mix the cement and sand with water due to evaporation of air voids there is reduction in volume by 42%
Dry volume = (wet volume) (1.42)
Dry volume = (163.024) (1.42) = 231.49 cubic feet
Sum of ratio = 1+4= 5
Calculation of cement bags
Cement = = 46.298 cubic feet
Volume of one bag of cement = 1.25 cubic feet
Total number of bags = 46.298 / 1.25 = 37 bags = 1850kg
Calculation of sand
Sand = = 185.19 cubic feet
Quantity of water
Water cement ratio = weight of water/ weight of cement
Usually w/ c = 0.5
Weight of water = 1850 0.5= 925kg (liter)
From above estimation it can be concluded there are some technical aspects which need to keep in mind for the estimation of plastering materials
first of all, total surface area where the plastering is required, should be calculated and then for the calculation of volume multiply it with standard thickness of plastering.
Dry volume without aggregates is about 1.42 times of wet volume so this concept must under consideration for correct results
All the surface area of doors, windows and any other hollow surface where plastering is not required should be deducted while during the calculations