Silicone

Silicone is applied with a gun to joints that move slightly or get wet, where a rigid groutGrout jointThe gap between tiles, slabs or stones, and the material that fills it. Grouting means filling these joints, which locks the surface together and keeps out water and dirt. would crackCrackA split or gap in render, concrete, a wall, a coating or wood. Fine cracks are usually only on the surface; ones that grow, keep reopening or run diagonally need attention.: between the tiles and the bath, at the base of a shower, around the basin and kitchen worktop, in the inside corners of tiled walls and around window and door frames. Once cured, it stays flexible.

Bathrooms and kitchens use sanitary silicone, which contains additives against mouldMouldFungi that grow on damp surfaces, leaving black or greenish spots and a musty smell. It is a symptom of damp, not a problem with the paint.. It goes onto a clean, dry surface. Silicone that has turned black with mould cannot really be cleaned: it is cut out, removed completely and replaced.

Ordinary silicone cannot be painted. Where the joint will be painted, such as between a window frame and the wall, a paintable sealant is used instead. And silicone is not waterproofingWaterproofingThe work and materials that stop water getting through on flat roofs, balconies, bathrooms, basements, planters and tanks.: it closes a joint, but it does not replace the waterproofing under the tiles or on a roof.