Paints are applied in multiple coats and each coat has specific function which is described below: 1. Primer: It is first coat of paint which is directly applied on the surface. its purpose is to wet the surface and to provide good adhesion for subsequently applied coats. 2. Intermediate Coats: Intermediate coats are applied to build the desired thickness of the surface. These may two, three or any no. of coats as required. Generally, the thicker the coating, longer the life. 3. Finished Coat: The finish coat provides the required appearance and surface resistance of the system. Depending on the conditions of exposure, it must also provide the first line of defense against weather and sunlight.