Section 9(3) in The Chennai City Corporation Building Rules, 1972
(3)If a masonry building exceeds one storey in height -(a)every wall must be solidly put together with -(i)mortar compounded with good cement and sand or other suitable material; or(ii)mortar compounded with good lime and sand or other suitable materials;(b)the proportion of the materials forming such mortar must be such as are approved by the Engineer;(c)no part of any wall other than a cornice or moulding shall overhang any part of a wall underneath it.
