Proper Prep and Seal for Black Slate

[schlameel]

I have just had beautiful black slate tile installed in my house by idiots. I'll save you the drama, but I have a chance to remove the installers from the project and finish the stone well. I need to seal the tile and grout but there are water deposits (I believe) on the surface of the tiles that make the black tile look gray. They installers came in and sealed the tile without cleaning it first and the floor is a stunning black puntuated and dappled with light spots and cloudy areas. I know it can be cleaned because they were blacker when we first got them and I scrubbed one tile as a test. It didn't remove all of the deposits in a little crack, but the rest was very clean and black.

So my questions:
* How should I prepare the slate to remove as much "stuff"
as possible so only black remains? Do I need to or can I remove the other
sealer? It was in a yellow bottle with circles of decreasing
size at the top.
* What brands of sealer would you recommend.

Thanks in advance for the advise.

John

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[jdm]

So does that make your installers the schlimazels, or just shysters?

[Mike2]

Hi John and welcome to the Forum. :)

Hate to hear story's like that...already been sealed you say....hmmmm.
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I'm moving this over to our Restoration section where the experts there will be sure to pick up on this. Will leave a "virtual" copy here as well. In the mean time do whatever you can to find out exactly what brand was used. That might help the restoration gurus come up with suggestions faster.

[schlameel]

Thanks Mike. I'll see what I can find out.

[schlameel]

I believe the sealer that was applied was TileLab Grout and Tile Sealer (http://www.tilelab.com/ProductCatalog/TileStoneCare/PenetratingSealers/GroutTile.aspx) .

[doitright]

Hi John, Welcome! :)

Any way you can post a picture?

It sounds like there may also be grout in the clefting.

You could TEST a small area with 50/50 vinegar and water, and come back here with your findings.

[schlameel]

The water and vinegar is to remove the sealer or the water spots or both? I'll try it in the closet.

The first image (I think) shows how the tile is cloudy and the texture of the stone is "highlighted" by the deposits.

The second image is a good comparison of the cleaned stone and an uncleaned stone. The tile on the left was not cleaned before the sealer was applied. The tile on the right was thoroughly scrubbed with water and towel dried several days before it was sealed. Cirlcled is the spot I mentioned in the original post where I was unable to clean the deposit out of a small crack. I used water and a tooth brush to try to clean the crack. I did my best to eliminate the reflected light in the photo.

The third image shows what looks like water spots. The stone is smooth where the light spots are. The picture also features the attention to detail employed by the bozos who did the work. Grrr. :bang:

[Michael of Stonehenge]

Hi S, Black slate is indeed a "Unique stone" related in a simple sense to oil shale. The bituminous oil like minerals in your natural stone are the sensitive issues. Acidic and alkaline materials have the ability to strip out these oils and leave you with blanched areas. The best suggestion I have for you is to call a local restoration pro and follow up your repair with a high quality solvent based enhancer or impregnator. Michael of Stonehenge