Submitted by marie on Mon, 08/20/2012 - 12:39

**Quantity take-off** or material take-off is the process of determining the quantity of construction materials needed to complete the work specified for a project. Take-off is taken from the project plans or working drawings.

A standard method of determining the quantity take-off is used for every trade. As an example, depending on which system of measurement is used, concrete is usually measured in either cubic meters, cubic feet or cubic yards.

On the other hand, drywall is measured in sheets, concrete masonry units(CMU) in pieces, floor finishes in square meters or square feet, paint in gallons or liters and caulking in linear meters or linear feet.

Example of a Quantity Take-off:

Determine the number of CMU to be used for a wall measuring 3 meters high and 5 meters high. Each concrete block measures 200mm x 400mm.

Area of Wall: 3 x 5 = 15 square meters

Area of CMU: 0.2 x 0.4 = 0.08 square meter

No. of CMU: 15 / 0.08 = 187.5 or 188 pieces

To continue further, the volume of grout to fill the cavities of each block needs to be computed. There are 3 cavities in each block measuring 75mm x 150mm.

Volume of Cavity: 0.075 x 0.15 x 0.2 x 3 = 0.00675 cubic meter

Volume of Grout: 0.00675 x 188 = 1.269 cubic meters

Before the advent of quantity takeoff software, materials take-off is usually done manually with only the help of a calculator and an architect's scale. This is a tedious and time-consuming process which is also prone to errors and omission.

Nowadays, a wide array of these software are available in the market for contractors to choose from. An estimate which took hours to finish in the old days could now be completed in a matter of minutes.

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