How to Remove and Prevent Efflorescence from Coming Back?


How do you remove efflorescence from terra cotta tile that extends under the front door. Inside the tile was covered with laminate flooring 25 years ago. This problem just started last year. Is there something I can coat it with to prevent it from coming back.


ANSWER - Severe efflorescence is a symptom of an excessive moisture problem.  Removing the efflorescence stain is treating the symptom rather than the problem.

Efflorescence is a mineral stain.  Minerals are forms of salts that dissolve in water.  The underlying moisture under the Terra Cotta tile migrates to the surface of porous tiles to evaporate.  As the moisture evaporates it precipitates the minerals that can cause spalling (tile surface degradation) from the expansion of the minerals.  The precipitated minerals causes the staining.

If the staining is typical white calcium material it can be easily cleaned up with water and a tile cleaner for removing efflorescence.  The cleaners a mild diluted acids, so it is better to use a store bought product for removing the efflorescence staining.

If you are not fixing the excessive moisture problem, then the condition will reoccur.  You can try to apply a penetrating sealer over the tile to try to minimize the staining, and make it easier to clean, but it won't prevent the staining.

4 thoughts on “How to Remove and Prevent Efflorescence from Coming Back?

  1. Connor Burke says:

    Good Day,
    Have you seen any situations on exterior tile, where by the stains become visible through the grout lines as noted in the pictures.
    Please note, Prism Grout was used.
    The Tile is less than one year old on a new build.
    Any insight is much appreciated.

    • Donato Pompo says:

      As my other responses indicate above, heavy efflorescence staining is a symptom of a moisture problem. Moisture is getting behind the tile and then migrates out through the porous grout joints. Along the way the moisture picks up minerals that dissolve in the water like salts and as the moisture evaporates out of the grout joints it precipitates the minerals leaving the efflorescence staining. If you can stop the moisture from getting behind the tile you can stop the efflorescence staining in theory.

  2. Debbie C says:

    It appears that we have efflorescence staining coming through the grout joints on our 6th floor condo balcony. Porcelain tile was installed throughout the condo 15 years ago and the only place this is happening is on the balcony. We had it cleaned by a tile/grout cleaning company 10 weeks ago and it seems somewhat worse now. It may be unrelated but our building had an extensive concrete restoration completed about 1 year ago. What would you recommend for next steps in our investigation?

    • Donato Pompo says:

      Recently we have inspected a lot of condo and hotel balconies that have excessive efflorescence staining. The key problem is a moisture problem where water is getting in the underlying materials beneath the tile and it isn’t allowed to readily drain away. If you can eliminate the moisture, then you can eliminate the efflorescence precipitation.

      Without intrusively removing tiles to inspect the underlying conditions, you can’t determine what was done wrong to create this condition. It could be a design deficiency and/or an installation deficiency.

      The only way to fix those likely deficiencies is to remove the tile assembly and properly re-install the tile. You need someone who really understands the industry standards and those applications to ensure that it gets replaced properly.

      Although we have recommended a repair method that theoretically can work if done properly that can keep the moisture from getting under the tile. That is to cut out all of the grout joints between the tiles and at the perimeters and replace them with an ASTM C920 traffic grade sealant (caulking) tooled to a concave finish such as a self leveling silicone or polyurethane. In theory, the keeps water from migrating beneath the tile and provides additional movement joints to mitigate potential movement stresses within the tile assembly. Of course, it has to be done correctly or it won’t work and can be problematic.

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