Section 52(2)(c) in Tamil Nadu Combined Development and Building Rules, 2019
(c)Damp-Proof(i)Every wall and pier of the building except when built on materials such as steel or reinforced cement concrete shall be provided with a dampproof course.(ii)Damp-proof course shall be laid at a level not higher than the lowest part of underside of the construction of the ground floor and shall extend to the full width and extent of such walls or piers. It shall be at least two centimeters thick. Where the damp-proof course is provided below the plinth level, vertical damp-proof course shall be provided between the floor and the inside of the plinth.