Tiles are also often used in rooms where there is some humidity in the air such as bathrooms, shower rooms and kitchens. This often leads to the growth of mould or mildew on grouting which is porous and therefore becomes unclean speedily. Apart from looking bad, mould and mildew also have an effect on our health as their spores have been linked to a range of unpleasant, even serious, medical conditions. Finally, dirty floor tiles can become hazardously slippery, especially when they are wet.