Tile and Stone Maintenance

Stain Removal from Natural Stone and Porous Grout

If all stone and grout were properly sealed and maintained the problem of staining would occur much less frequently. However, for numerous reasons surfaces are not always treated with the care they require and with the continued growth in the use of natural stone as a popular flooring material, the problem of staining will be around for the foreseeable future.

Staining occurs when a contaminant is allowed to dwell on the surface of the stone. If the contaminant is allowed to disperse to a level from where it cannot be extracted through the surface, it becomes a stain. Finding a suitable cleaning chemical to re-emulsify that stain is usually possible (providing the nature of the contaminant is known) but getting the chemical to magically lift the contaminant to the surface for complete removal is another matter.

When attempting to remove stains, many experts adopt the following procedure:

Step 1. Remove the contaminant as quickly as possible after exposure as this will minimise its’ staining potential. This should be done by absorption only, not by agitating or scrubbing. The best way to do this is to use a clean sponge or (something absorbent) to absorb the excess contaminant. Do this carefully without pushing it around, this way the contaminant will not be spread further over the surface. The absorption effect will also help to pull the contaminant upwards to the surface, facilitating its’ removal later. If you are faced with an already ‘dried’ stain then go straight to step 3.

Step 2. Leave the remaining contaminant to dry. It might seem a little odd at first, but once you have removed as much of the contaminant as possible through absorption, there is little more to be gained by scrubbing or trying to wash with a cleaning solution. Indeed, adding further liquids at this stage risks driving the contaminant deeper into the stone.

Step 3. Once the contaminated area has dried, an appropriate cleaner can be applied. In order to select the appropriate cleaner, reference should be made to both the material being cleaned (is it an acid sensitive stone like marble?) and to the nature of the contaminant itself. The cleaning solution should be applied in accordance with the manufacturers’ instructions and left to dwell. This is very important as it takes time for the cleaner to re-emulsify the now solid contaminant. Once the chemical has had time to dwell, absorb as much of the residue as possible with a clean dry sponge. Do not attempt to scrub or agitate at this stage rather repeat this step one or more times until you are certain that no more can be achieved. Only on the last application should you attempt to agitate if required (and it often is). It is always best to leave agitation as a last resort as it can also further disperse contaminants to unstained areas. So the main point is to try to extract as much of the contaminant initially, thorough careful absorption before scrubbing.

This simple procedure should in most cases provide good results. If the staining is proving more difficult then consider using a poultice paste. There are several on the market, some are pre-made so you need to know what type of cleaning agent they are mixed with. Others like Poultice Stain Remover by Aqua Mix are in a dry powder form, this is generally a safer and ultimately more flexible option as you can choose to make up your paste with plain water for delicate situations or with stronger cleaning solutions for more complicated stains such as oils.

Mix up the poultice with the chosen cleaning agent (often clean water is sufficient) into a thin paste. Apply to the stain (overlapping by about 20%) and cover with plastic film. Leave for 24 hours, then carefully remove the now dried poultice and rinse with clean water. If there is still a stain present, repeat the procedure until it has gone.

This technique can often provide great results when other methods fail. However, care should be taken on some stones such as dark (green and black) marbles as a poultice can occasionally ‘pull’ colour from these stones. As always, test a small area first to be sure.

Copyright Ian Taylor and The Tile and Stone Blog.co.uk, 2013. See copyright notice above.

1 Comment

  1. Frank @ Search for xmas trees

    Should we buy porcelain tile from home depot? Our contractor is telling us not to because the quality is bad?

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