Where the bath meets the tile, it is necessary to seal the joins with a silicone rubber caulking. This is necessary as the fitting can move enough to crack a rigid seal, causing the water to penetrate the wall between the bath and the tiling, leading to further complications with dampness and possible leaks to the ceiling below. There are various coloured sealants available to blend in with your fixtures and fittings. They are sold in tubes or cartridges made to deal with gaps up to a width of 3mm (1/8 inch). If you have a larger gap to fill, pack it with twists of soaked newspaper or soft rope. Always fill the bath with water before sealing, to allow for the movement experienced when the bath is being used. If you fail to do this, you will probably find the sealant cracking fairly early on, due to the different stress placed on it from the bath being empty to full. This movement is unlikely in cast iron baths, but definitely needs to be taken into account for most other materials. Alternatively ceramic coving is available or quadrant tiles can be used to edge the bath or shower tray. Plastic strips of coving are also available, which are easy to use and cut to size. It is wise to fit the tiles using water resistant or waterproof adhesive and grout (see Grouting).