Powdery efflorescence in sunroom

[nihil]

We've been getting a whitish powdery efflorescence every winter in our sunroom. The floor is a slate (??) tile and the powder appears in the seems between slabs.

What is the best way to clean this up and keep it from happening every year?

Thanks for any suggestions

Pic of powder

 

[jqgs214]

Looks like something leaching out of the cement base or grout.

 

[nihil]

Looks like something leaching out of the cement base or grout.

Agreed.

How best to clean it and how to keep it from happening again?

 

[Jay H]

Looks like something leaching out of the cement base or grout.

Agreed.

How best to clean it and how to keep it from happening again?

Check out UGL Drylock stuff:

http://www.ugl.com/drylokMasonry/floorAndExteriorPaints/latexConcrete.php

I know they are recommended to seal against the water seepage that is causing the effluence. However, I am unsure how to recommend something to you that is happening in the grout. Would you have to remove the tile and apply the Drylock underneath and then retile it or could you just apply it to the grout?? I am unsure but perhaps you can ask UGL to see what they recommend... Sounds like removing the tile may be hard work or risky if you can't get tile replacements...

Jay

 

[burntime]

Is there a drainage problem around the sunroom? Hydronic presure would force water up if I am not mistaken. Drylock would work if you could pull up the tile, drylock it, and reapply the tile. Thats not really practicle. First fix the water issue or the rest is a bandaid.

 

[nihil]

Alas its not realistic to take up the existing tile. The sunroom is on a brick foundation (I think). It was in place when we bought the house.

I was wondering if sealing the gap between the bottom corner of the sunroom and the brick foundation would help the problem. Not sure what caulking to use that would adhere to both brick and wood.

 

[dvellone]

The efflorescence occurs because of excessive moisture behind the masonry. The only way to prevent it is by eliminating the moisture.

 

[johnn]

The use of a water level and some masons line could determine if this is a low spot in the flooring, creating a holding area for water. That would only point towards trying to find the penetrtation area. a Picture of the crack you mentioned could help, however not being able to determine the construction yourself,,,I dont know that they will help us. If it is a slab,, then before mentioned, Hydronic pressure is likely. A french drain dug around the perimeter should fix the problem.
I could be totally wrong; But WXMANN may not have been describing what he saw in the picture,,,rather pointing out that "Efforescence" can/or may be caused by the chemical compounds of the materials. I believe I read that while doing searches on different Brick Manufacturers and reading on"efforescence" problems and cures.

 

[Cutter]

Indeed, the deposits you are seeing are what are considered salts. They are calcium carbonate in make up and can be cleaned up with any weak acid. Vinegar will work. Do make sure that you use plenty of water afterwards to dilute any residule acid. A good sealer will only promote the salts growing elswhere. Like under the slate. Which with time will loosen the adhesinve or motar bed they are set in.