How to estimate various building quantities
If you want to compute the building quantities which are part of earth work, foundation concrete, brickwork in plinth and super structure, the following two methods are very useful:-
a) Long wall - short wall method
b) Centre line method.
c) Partly centre line and short wall method.
a) Long wall-short wall method: Under this system, the wall adjacent the length of room is supposed to be long wall and at the same time the wall upright to long wall is called as short wall. To determine the length of long wall or short wall, it is suggested to initially work out the lengths of centre line concerning individual walls. Afterward, compute the length of long wall, (out to out) once half breadth is included at each end to its centre line length. Thus the length of short wall is calculated by subtracting half breadth out of its centre line length at each end. The length of long wall generally reduces from earth work to brick work in super structure whereas the length of the short wall is raised. To obtain the quantities, multiply these lengths with breadth and depth.
b) Centre line method: This method is best suited for walls of similar cross sections. It order to obtain the whole quantity at once, the total centre line length is multiplied with breadth and depth concerning certain item. While binding cross walls or partitions or verandah walls with main wall, the centre line length is decreased with half of breadth for individual joint. Such joints should be analyzed cautiously when calculation is made for complete centre line length. This estimating system is considered as most accurate and fast.
c) Partly centre line and partly cross wall method: If external (i.e., around the building) wall is built up by one thickness and the internal walls contain various thicknesses, this method will be most suitable. For this purpose, centre line method is implemented to external walls and long wall-short wall method is implemented to internal walls. This method is ideal for dissimilar thicknesses walls and foundations having unlike levels. For this reason, this method is mostly recognized by all Engineering departments.