Methods of taking out quantities

Quantities of a building (mainly walls and foundation) are taken out by the following methods.

1. Long wall and short wall method

• Walls running in the long direction are called long walls; those running in the short direction are short walls.
• Long wall length (out-to-out) = centre-to-centre length + half the width of the trench/wall at each end.
• Short wall length (in-to-in) = centre-to-centre length - half the width at each end.
• Each wall is multiplied by its own width and depth. It is accurate but needs more calculation; it suits walls of different thicknesses.

2. Centre line method

• The total centre-line length of all walls is found and multiplied by the section (width x depth) of the wall or foundation.
• Where walls meet, half the width of the wall is deducted from the total length for each T-junction (a cross-junction counts as two T-junctions).
• It is quick and best for buildings with uniform walls and rooms of the same type.

3. Partly centre line and partly cross wall method

• Used when the outer walls have one section and the inner (cross) walls another. The outer walls are measured by the centre line method, and the cross walls are measured separately by their in-to-in lengths and multiplied by their own section.

4. Individual wall (separate wall) method

• Each wall is measured one by one.

5. Bay method

• The building is divided into bays between columns, and each bay is measured; it is used for framed structures and sheds.

6. Unit (approximate) methods

• Cost per unit area/volume for a quick estimate.

In practice, the long wall-short wall and centre line methods are the two used in building estimates in Nepal.