Grout joint

Tiles and stones are not laid tight against each other. A small gap, the joint, is left between them to take up small differences in size and the movement caused by heat and cold. Once the adhesive has set, the joints are filled with grout, a fine mortar that comes in many colours, or, where more resistance to water and stains is needed, with an epoxy grout.

Large surfaces such as roof terracesFlat roof (roof terrace)The flat concrete roof on top of a building. It is the most common kind of roof in Greece and the part that takes the most sun and rain., courtyards and stone pavingStone pavingA floor of natural stone slabs, irregular or cut, in courtyards, walkways, terraces and on steps. The stones are bedded in mortar and the joints between them are filled. also have expansion joints: wider joints that divide the floor into sections so it can move without crackingCrackA 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.. These are not filled with a rigid material but with a flexible sealant.

Over the years, joints darken, crumble or open up. In bathrooms and kitchens a failing joint collects 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., and on terraces and balconies joints are among the first places water gets in. Worn joints are raked out, cleaned and filled again. Along a bath or shower tray, where there is movement, silicone is used instead of grout.