Calculation of material and labour requirement for rubble masonry incement mortar 1:5 in foundation

Random Rubble Masonry in Cement mortar 1:5 in foundation (1Cu)

Description	Unit	Quantity
6”-9” Rubble	Cu	1.3
Cement (50kg bags)	Nr	5
Sand	Cu	0.3
Water	Gal	100
Mason	Day	1
Unskilled labourer	Day	3
Total

Generally, to construct a rubble foundation, the materials required are rubble, cement, sand, and water. Mixing of cement and sand mortar ratio can be changed depending on the strength should obtain but the most frequently used ratio is 1:5 (cement:sand) mix, which we are going to discuss in this article.

In the above table, material and labour requirement for 1 Cube of rubble masonry work have been indicated based on the field experience and building schedules of rates. In this calculation, it is necessary to add 5-10% of wastage for sand. 

Ex:- Assume we have to construct a rubble foundation, which is 450mm in width, 600mm in height and which is 50m long. Assume water is available at the site. What are the material and amount of each material are we going to purchase to get the work done.

First, we need to calculate the total actual volume of rubble work.

 V = 0.45m x 0.6m x 50m
     = 13.5 m3
     = 4.77 cube 

According to table given,

Rubble = 4.77 x 1.3 Cube
             = 6.20 Cube

Cement = 4.77 x 5 Bags (50kg)
              = 23.85 Bags
              = 24 Bags

Sand = 4.77 x 0.3 Cube
         = 1.43 Cube

Add wastage 5% = 1.43 x 5%
                            = 0.07 Cube

Total Sand Requirement = 1.50 Cube

Therefore your Purchasing order should be;

Rubble = 6.20 Cu
Cement = 24 bags (50kg)
Sand = 1.50 Cu

Note: When we issue the payments for the labours, consider only the actual volume of rubble masonry and not the amount of purchasing of rubble.

Therefore, payment should be issued for labour for this work is 4.77 cu (Skilled labour days 4.77 and  unskilled labour days 14.31). 

Note: 1cube = 100 cu.ft = 2.83 cum

Typical Rubble Foundation Detail

Check Out the Rubble Masonry Calculator