All about civil construction knowledge- PARAM VISIONS

Calculating the cost of stone (random rubble) masonry work./Rate analysis of random rubble (stone )masonry work.

 Let us consider RR ( stone ) masonry wall for the calculation purpose as shown in the below drawing.

Given data:

Length of the stone masonry wall = 15 ft.

Height of the stone masonry wall = 7 ft.

The thickness of the RR masonry wall = 1.5 ft.


The total volume of the RR masonry wall

= [length × height × thickness]

= [15 ft. × 7 ft. × 1.5 ft.]

= 157.5 cu ft.


Before proceeding further, go through the article 👇

👀 . What is random rubble masonry? - Thumb rules in RR masonry calculations. 

to understand the calculation procedure without any questions.


A. Material calculation:

1.  Volume of  rubble stone:

The required vol. of stone 

= [1.25 × the vol. of RR masonry wall]

= [1.25 × 157.5 cu ft.]

= 196.875 cu ft.


2. Cement mortar:

The required dry vol. of cement mortar

= 40% of the vol. of RR masonry.

= [40 × 157.5 cu ft. ÷ 100]

= 63 cu ft.


Let us build this wall in the cement mortar of 1:6 ratio 

 a.  The volume of the sand

         = [{its ratio  ÷ ( total ratio)} × dry mortar vol.]

          = [{6  ÷ ( 6 + 1)} × 63]

           = [0.8571 × 63]

           = 54 cu ft.   or 

         = 1.53 cum.


b. Volume of the cement 

   = [total dry mortar vol. - volume of sand]

    = [63 cu ft. - 54 cu ft.]

    = 9 cu ft.

As you know, one bag of cement = 1.226 cu ft.

  Number of cement bags 

    = [9 cu ft. ÷ 1.226 cu ft.]

    =   7.34 bags.


B.  Labor calculation:

The labor rate per cu ft. of the RR masonry work ranges from INR 10/- to 16/- depending upon the region.

Let us consider an average rate of INR 13/- per cu ft.

The total cost of labor for RR masonry

   = total vol. of RR masonry in cu ft.  × labor rate/ cu ft.

   = 157.5 cu ft. × 13/-

   = INR 2,047.5/-


Now, let us calculate the total cost of RR masonry in table format.

Sl. no.

Item.

Qty.

Rate.

in INR.

Unit.

Cost

in INR.

1.

Rubble stone

 196.88

        35/-

Cu ft.

   6,890.80

2.

Cement

     7.34

   380/-

bag

   2,789.20

3.

Sand

   54.00

   60/-

Cu ft.

    3,240.00

4.

Curing

Lump-sum

        200.00

5.

Miscellaneous

Lump-sum

        275.00

6.

                                                      The material cost =

  13,395.00

7.

                                                       Add 5% wastage =

        669.75

8.

                                                   Total material cost =

  14,064.75

9.

                                                                Labour cost =

      2047.50

10.

    The total cost of RR masonry wall =

   16,112.25

 

Note: To get accurate results, insert your regional market rate of materials & labor, in the above table.


a. The cost of random rubble masonry/cu ft.

= [total RR masonry cost ÷ total masonry vol. in cu ft.]

= [16,112.25 ÷ 157.5]

= INR 102.30 /cu ft.


b. The cost of random rubble masonry/cum.

   = [102.3 × 35.3147]

  = INR 3,612.70 / cum.

( As 1cum = 35.3147 cu ft.)


Note:

 If the work is handed over to any contractor, you have to add 10% extra for his profit.


Thank you for going through this article. Have a good day😄.

If you have any quarries, you can ask me in the comment box👇.



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