Overview
To calculate the cost of any masonry built using bricks and mortar, you should consider the following topics:
- Standard size of bricks used
-The standard size of brick being used in Nepal is 240*115*57mm.
- Thickness of the mortar
-We consider the standard thickness of 10 mm of mortar for brick work.
- Mix ratio of mortar
-The mix ratio normally used is either 1:6 or 1:4 (cement and sand).
You can bond bricks in different patterns, like
- English Bond
- Flemish bond
- Stretcher bond
- Rat Trap Bond, etc.
Among different types of bond, the most commonly used brick pattern in Nepal is English bond. The English bond is one of the strongest bonds. In this bond, we use an alternate row of stretchers and headers. We'll discuss about bricks bond in next blog, here we are going to deal with English bond and it's cost estimate. This analysis is based on first-class chimney-burnt bricks following the norms of
- Kathmandu District rate of fiscal year 079/80
- DUDBC Norms
Regarding these norms, you can see them in our previous blog: https://www.ieccc.com.np/2024/06/cost-of-m20-grade-concrete-in-Nepal.html.
Let's break down the rate analysis process into four major headings.
- Materials estimate and cost as per KTM district rate: 079/80
- Workers estimate as per DUDBC norms.
- Cost of tools and equipment
- Overhead cost and profit
Calculation
Let's consider 1 cubic meter (m3) of brick work.
Calculation of brick numbers
Size of Bricks: 240 * 115 * 57mm
Volume of brick = 0.24 * 0.115 * 0.057
= 0.0016 cu.m
Size of brick with mortar: 250 * 125 * 67 mm
Volume of brick with mortar = 0.25 * 0.125 * 0.067
=0.002 cu.m
Number of bricks in 1 m3 of brick masonry = (volume of brick masonry) / (size of brick with mortar)
= (1) / (0.002)
= 500 nos.
Calculation of mortar (let’s say 1:6)
Volume of 500 bricks without mortar: 500 * 0.0016
= 0.8 cu.m
Therefore, volume of mortar: Masonry Volume - Volume of bricks
=1-0.8
=0.2 cu.m
Dry Volume of Mortar: 1.33 * wet volume (we take 1.33 for mortar)
= 1.33 * 0.2
= 0.266
Volume of cement: (Cement Ratio * Dry Volume of Mortar) / (Sum of Ratios)
=(1 * 0.266) / (1 + 6)
= 0.038 cu.m
Cement in kg: Volume * Density
= 0.038 * 1440 (Density of cement = 1440 kg/m3)
=54.72 kg
Number of bags of cement: 54.72 / 50 (1 bag of cement = 50 kg)
=1.09 bags
Volume of sand: (Sand Ratio * Dry Volume) / (Sum of Ratios)
=(6 * 0.266) / (1 + 6)
=0.228 cu.m
Volume of water: 100 liters as per DUDBC norms
Cost of material as per district rate in Kathmandu 079/80
First Class Chimney Burnt Bricks: 500 nos. at Rs. 15.12 = 500 * 15.12 = Rs. 7560
Cement: 1.09 bags at Rs 700 = 1.09 * 700 = Rs.763
Sand: 0.228 at Rs 3319.61 = 0.228 * 3319.61 = Rs. 756.87
Water: 100 ltr at Rs. 0.2 = 100 * 0.2 = Rs. 20
Cost of Materials = 7560 + 763 + 756.87 + 20 = Rs. 9099.87
Workers as per the norms of the DUDBC
Skilled Workers: 1.5 per cubic meter of brickwork
Unskilled Workers: 2.2 per Cu.m Brickworks
Cost estimate of workers as per Kathmandu District rate: 079/80
Skilled workers: 1.5 at Rs. 1185 = 1.5 * 1185 = Rs. 1777.50
Unskilled workers: 2.2 at Rs. 870 = 2.2 * 870 = Rs. 1914.00
Total of Workers Cost = 1777.50 + 1914.00 = Rs. 3691.50
Analysis of the Cost of Tools and Plants Used
Cost of equipment and tools: 3% of unskilled workers
=3% of 1914
=Rs.57.42
Total Cost = Material Cost + Workers Cost + Cost of Tools and Plants
= 9099.87 + 3691.5 + 57.42
= Rs. 12848.79
Overhead and profit of contractor analysis
Contractor overhead and profit = 15% of total cost
=15% of 12848.79
=Rs. 1927.31
Total of cost including contractor overhead = 1927.31 + 12848.79
= Rs. 14776.10
Summary of the Rate Analysis
Brick masonry works include supplying bricks, making cement sand mortar, and constructing brick walls, including the haulage distance of up to 30 m for first-class Chimney (Bhatta) bricks (1:6 cement sand mortar). |
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Brickwork for 1 cu.m. |
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Description |
Type |
Unit |
Quantity |
Rate |
Amount |
Remarks |
Workers |
Skilled |
MDay |
1.5 |
1185 |
1777.50 |
|
Unskilled |
MDay |
2.2 |
870 |
1914.00 |
|
|
Materials |
Bricks |
Nos. |
500 |
15.12 |
7560.00 |
|
OPC Cement |
Bags |
1.09 |
700 |
763.00 |
|
|
Sand |
Cu.m |
0.228 |
3319.61 |
756.87 |
|
|
Water |
ltr |
100 |
0.2 |
20.00 |
|
|
Equipment |
Tools and plants |
- |
L.S |
3% of unskilled workers |
57.42 |
|
Sub-Total |
12848.79 |
|
||||
Contractor Overhead: 15% |
1927.31 |
|
||||
Total |
14776.10 |
|
Others
In a similar way, you can calculate rate analysis for brickwork for 1:4 cement sand mortar too. The procedure is the same for machine-made bricks and second-class chimney-burnt bricks too. In some cases, they place a separate heading for scaffolding costs; this cost is covered under tools and plants in our case.
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