Section 142(4) in West Bengal Municipal (Building) Rules, 2007
(4)(a)No construction shall be done except in masonry works. Every building, except in case of open building, shall have outer walls forming a part thereof constructed of brick, stone or other hard and incombustible substance approved by the Authority. All walls of masonry building shall be properly bonded;(b)Single brick thick, that is, 25 cm (10") load bearing wails, can be adopted up to three storied residential building if constructed in cement mortar of requisite proportion;(c)in the case of residential buildings or flats where maximum height of rooms measured from the surface of the floor to the ceiling is restricted to 2.75 m (9'-0"), load bearing walls of 25 cm (10') thick can be adopted up to four stories buildings, provided good bricks of 70 kg/cm strength are used with cement mortar as specified by the National Building Code;(d)every wall of masonry building which is exposed to external air shall, in no case, be less than 25 cm in thickness :Provided that where load-bearing walls of 25 cm (10" thick) has been specified, use of 20 cm thick modular brick work may also be adopted up to three storied buildings only. In case of outer wall (not being load-bearing), 20 cm thick modular brick work may be adopted in all cases.
