Efflorescence Staining from Moisture Perhaps?


The property is a ground garden unit with a big patio oceanfront. An amber color sticky substance is seeping through the grout of the cement floor with ceramic tiles. The building is pour cement with re bar. The area started in the living room and through time has expanded, specially after being flooded with hurricane Maria.

The substance makes a tiny hole through the grout and comes out eventually creating a white mark on tile. it covers an area of 2 inches or less on the grout line and you can see the spots in different places usually not longer than that, The substance is thick and sticky lasting that way for a long period of time. As an experiment, in some areas the grout was removed and hydraulic cement was placed covering the hole where it was oozing. As is a second home, couple of days passed by with windows and doors closed and the pattern was repeated. In some places was not able to seep through the cement and did seep through the joints of the cement and the tile.

It is a very hard cement tile notwithstanding I did notice one tile already showing signs that the substance will carve a tiny hole in it. Of all ground level units, 5 only, this is the only one showing problems. As beachfront, the building site was elevated and in front of unit there is a contention wall to retain the grounds. That wall was reconstructed two years ago as erosion due to water was taking it down in some places. At the time french drains were build in my patio to divert water accumulation. The tile situation already existed at that point in time but previous owners did not act upon it. The amber color, viscosity and stickiness of the substance have me puzzled as also does the way it seeps, as a tiny hole in the grout Can we conclude that it started as water and was organically changed in the seeping process or what else can it be and , of course, what can I do to remedy the situation.

Enough said as my head is already spinning. I truly and absolutely rely in your wisdom and expertise. I live in an island and resources to address this situation are non existant.
In appreciation of your advise, I will be forever.


ANSWER - You have provided so much information that it is a little confusing.   So I will make some assumptions.

You said that your tile patio is part of an ocean front home. You said the problem started after the tile was flooded from a hurricane. You said that a white sticky substance was seeping through the grout joints.

This sounds like you have an extreme efflorescence staining condition, which is a symptom of a moisture problem.   Efflorescence is normally a calcium based substance.  Because of excessive moisture under the tile, natural minerals (a form of salts) in the ground, and the underlying concrete and in the tile will dissolve into the moisture like salt dissolves in water.  The moisture then migrates to the surface of the grout and/or tile where the moisture evaporates.  As the moisture evaporates, the minerals precipitate into a white substance that can be sticky substance and eventually can dry out and get crusty or powdery.   Normally if you take vinegar, a diluted acidic solution, it will dissolve the the efflorescence and effervesce (give off bubbles) in the solution.

So the efflorescence can be cleaned off of the surface, but that does not fix the problem of having excessive moisture.  The moisture could be due to a high water table or it could be a hydrostatic condition where water from a higher level is draining down to the lower level under your patio deck, which can be destructive.

In order to fix the problem, you have to determine where the moisture is coming from.  That may require a forensic investigation by intrusively removing some of the tiles.  Some solutions might be by putting in french drains around the perimeter of the patio to divert the water away.

2 thoughts on “Efflorescence Staining from Moisture Perhaps?

  1. Steve Schlag says:

    We have a very similar situation……Any type of barrier that can be put on top of the stone to prevent the goo from coming through or does stone floor have to be removed and a barrier placed underneath before new stone is added?
    Thank You!!! Steve

    • Donato Pompo says:

      Treating the stone is only treating the symptom of the problem. It does not eliminate the problem which is the source of the moisture. To prevent the efflorescence you have to stop the source of the moisture.

      If the efflorescence is coming through the stone then you must have a porous stone. It can’t be marble because to be a true marble it can’t have more than 0.2% absorption, which means it is impervious.

      There are some porous stones where you can seal them with a penetrating sealer and it will slow down the moisture migration, but it is only a partial and temporary solution.

      Depending on the geological classification of the stone there is company who produces sealers called Prosoco who claims to have sealers for calcium carbonate stones that can help block the pores.

      Otherwise to correct the problem you need to locate the source of the moisture and either divert it to a drain or block it in some manner.

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