Methods of Quantification

The quantities of various items such as earthwork excavation, foundation concrete, masonry in foundation and basement, masonry in superstructure etc. can be estimated by 

any one of the following methods whose brief description is given below : 

1. Long and short wall or "out-to-out" or "in-to-in"  method 
2. Centre line method 
3. crossing method 

Long and Short Wall or "Out-to-Out" or "In-to-In" Method 

Longer walls in a building (generally one direction) are considered as 'long walls' and measured from 'out-to-out'; and shorter or partition walls, perpendicular to the longer:  walls, are considered as 'short walls' and measured from 'in-to-in' for a particular layer (level) of work. These lengths of long and short walls are multiplied separately by the breadth and height of the corresponding layer and are added up to get the total quantity for that layer. Such lengths of long and cross walls are computed for every layer in which the breadth changes. To calculate the lengths of long and short walls, their centre to centre lengths are individually determined from the plan. Then the length of the long wall out-to-out is calculated after adding half breadth of wall at each end to the centre-to-centre line length. The length of long wall generally decreases from earthwork to brickwork in superstructure whereas the length of short wall increases. In case of short walls, the length of short wall is computed by subtracting the half breadth of wall at each end to the centre-to-centre line length. 

Centre Line Method 

The total centre lines of walls in a building are calculated and the breadth and width of the respective item to get the total quantity at a time multiply the same. For different section of walls in a building, the centre line length for each type shall be worked out separately. In case of partition or veranda walls joining the main walls, the centre line length shall be reduced by half of the breadth of the layer of main wall that joins with the partition or veranda wall at the same level. Number of joints is first studied to calculate the centre line length. In case of unsymmetrical wall, the centre line varies at every layer. 

Crossing Method 

To obtain the centre line length, the overall perimeter of the buildings are calculated and subtracted with four times the thickness of the wall. Internal walls are grouped separately to their sections and measured in between the internal faces of the main wall at that level.