Rate analysis is a crucial step in construction projects as it helps determine the cost of materials and labour involved in the work. For brickwork, the primary components to analyze are the quantities of bricks and mortar required, as well as the labour needed for masonry work. This article will guide you through the process of estimating these quantities and calculating the rate analysis for brick masonry.
Quantity Estimation for Brick Masonry
To simplify the rate analysis, we take 1 cubic meter (1 m³) of brick masonry as the standard unit for calculation.
Number of Bricks Required
For 1 m³ of brick masonry, the number of standard-size bricks needed is approximately 494 bricks. This standard count helps in consistent estimation and budgeting.
Quantity of Mortar
Mortar is the binding material used between bricks, and its proportion can vary depending on the type of construction. Common mortar mix ratios include 1:2, 1:4, 1:6, and 1:8 (cement to sand by volume).
For 1 m³ of brick masonry, mortar typically makes up 25% to 30% of the volume. This means the quantity of mortar required ranges from 0.25 m³ to 0.3 m³. For calculation purposes, it is common to consider the higher value of 0.3 m³ of mortar per cubic meter of brickwork.
The specific quantities of cement and sand in the mortar can be calculated based on the mortar mix ratio chosen.
Labour Estimation for Brick Masonry
Labour is a significant part of the cost in brick masonry and includes:
- Mason who lays the bricks.
- Labourers responsible for carrying materials such as sand, cement, bricks, and water.
- Labour for mixing and transporting the mortar.
The labour requirement is typically expressed in man-days per 1 m³ of brickwork.
- The mason’s work for 1 m³ of brick masonry generally requires 0.94 days.
- Labourers combined for tasks such as material carriage, mortar mixing, and transportation usually require 1.57 days.
Other costs such as tools and transportation are accounted for as lump sums, which vary depending on the project location.
Rate Analysis of Brick Masonry
Once the quantities of materials and labour have been estimated, the next step is to assign costs to each component.
Materials and Labour Rates
The rates for materials like cement, sand, and bricks, as well as labour charges for masons and helpers, can vary significantly based on location and time. These rates can be obtained from:
- Local market prices.
- Published schedules of rates for the particular region.
Final Calculation
The rate analysis is performed by multiplying the unit rates of each material and labour by the respective quantities estimated for 1 m³ of brick masonry. Summing these gives the total cost for brick masonry work per cubic meter.
Conclusion
Performing an accurate rate analysis for brickwork involves careful estimation of both materials and labour quantities. Using a standard volume of 1 m³ of brick masonry as the basis, one can calculate the number of bricks, the volume of mortar required, and the man-days needed for labour. Multiplying these quantities by the current local rates results in a reliable cost estimate. This method ensures that construction budgeting is both transparent and accurate, aiding better project planning and management.