Terracotta tile lends a warm, earthy feel to any interior space, but the naturally porous material can also act like a magnet for dirt. Cleaning the tile with the wrong kinds of products may result in unsightly surface buildup or even damage to the finish. Several cleaning methods will remove all but the most stubborn stains from your sealed or unsealed terracotta.
Unsealed terracotta tile is highly porous since terracotta has no natural glaze. Sweep the tile regularly to remove surface dirt before it can be ground into the material. For ground-in dirt, use warm water and scrub gently with a soft brush. Never use a wire brush or other abrasive scrubbing material that may scratch the finish. Heavily stained or soiled areas usually come clean with muriatic or oxalic acid diluted with water to the manufacturer's specifications, followed by a clean water rinse.
Sealed terracotta has a protective coating, usually added after installation, that makes it more impervious to stains and easier to clean. Sweep regularly and mop with a mild household detergent, preferably a non-ionic detergent designed to clean greasy dirt without leaving residue on the tile's surface. Occasional use of a grout cleaner will keep the grout clean and white. For heavily soiled terracotta, hire a contractor to steam clean the floor, or rent a steam cleaner and do it yourself.
Cleaning Before Sealing
Because maintenance is much simpler on sealed terracotta tile, you may wish to have an older floor sealed or resealed. Before sealing, a thorough cleaning is in order to remove any existing dirt or stains. If you need to use chemical cleaners, rinse away all traces of the cleaner with clean water and allow the floor to dry for at least half an hour since the cleaner may interfere with the sealing product and prevent it from setting properly.
The porous nature of terracotta tile sometimes results in a problem called efflorescence, in which salts present in the environment precipitate on the surface of the tile, causing a translucent, off-white bloom. In most cases, efflorescence eventually wears off and disappears on its own over a period of weeks or months. You can remove it using a cleaner containing hydrochloric acid diluted according to the label directions, but it may reappear intermittently until the source of the salt is exhausted.