HOW WE DEVELOP THUMB RULE FOR DIFFERENT ESTIMATION OF THE BUILDINGS

For building rough cost or simple quantities estimates we mainly use the thumb rule. This rule doesn’t give us an exact quantity but provides us with an approx quantity that is nearly equal or less to the exact quantity.

What is the thumb rule?

The Thumb rule is defining as we develop a constant number with our past experience and our field daily work experience. For example 0.2, 0.5, etc.. by multiplying our desire covered area by the thumb rule which we develop for specific quantities we git approx quantities of the material.

For your better understanding lets take this example.

The Thumb Rule creation Formula

EXAMPLE:

Suppose we done 3 different house construction having a covered area of 1050 square feet each. In each house construction work different amounts of Cement bags, Sand, and Aggregates are consumed. To construct a this rule for cement, sand, and aggregates quantity estimations.

In 1st House Construction:

Cement = 600 Bags (just for example).

Sand = 2,000 cubic feet.

Aggregates = 1700 cubic feet.

In 2nd House Construction:

Cement = 590 Bags (just for example).

Sand = 1900 cubic feet.

Aggregates = 1600 cubic feet.

In 3rd House Construction:

Cement = 570 Bags (just for example).

Sand = 1800 cubic feet.

Aggregates = 1500 cubic feet.

THUMB RULE DEVELOPING:

To develop a rule for each construction material. We must take an average of the consumption of each specific material.

CEMENT:

Average Consumption = (600 + 590 +570)/3

= 586.66 bags.

Averagely consumption of cement was 586.66 bags. Now it is important to know how much cement was consumed in 1 square feet area.

Covered area = Material consumption.

1050 sft = 586.66 bags..

1sft = (586.66/1050) bags.

1sft = 0.55 bags

The o.55 is basically our cement thumb rule. Now if we need to calculate the quantity of cement for 5,000 square feet area (if the conditions are the same) we just multiply the 0.55 with our covered area we get the cement quantity.

SAND:

Average Consumption = (2,000 + 1900 +1800)/3

= 1900 cubic feet.

Averagely consumption of the sand was 1900 cubic feet. Now calculate sand was consumed in 1 square feet area.

Covered area = Material consumption.

1050 sft = 1900 cubic feet..

1sft = (1900/1050) cubic feet.

1sft = 1.8 cubic feet.

The 1.8 is basically our sand thumb rule.

AGGREGATE:

Average Consumption = (1700 + 1600 +1500)/3

= 1600 cubic feet.

Averagely consumption of the Aggregate was 1600 cubic feet. Now calculate sand was consumed in 1 square feet area.

Covered area = Material consumption.

1050 sft = 1600 cubic feet..

1sft = (1600/1050) cubic feet.

1sft = 1.52 cubic feet.

The 1.52 is basically our Aggregate thumb rule.

Note: It is very important to check the situation our which we are going to calculate the quantity. If the situation is similar to your old construction work (Our there you take the average consumption of the material) then these thumb rules are applicable.

Also Read:

•  How to find the volume of retaining wall?
• How to calculate the number of concrete Blocks?
• Civil Engineering different conversion units?

There is also watch a video on the youtube related to the same article (Thumb Rules)