I am in the process of removing a hazy sealant from a slate floor. I am using a stripper with methylene chloride. After this should I wash the floor with a vinegar/water or ammonia/water solution prior to resealing?

How long should I wait after washing the floor before I can safely reseal.

Thank you for your help,
Anita

Hello Anita. First of all, methylene chloride is nasty stuff. I would never recommend anyone use it without the proper respirator and experience. Secondly, I would follow the washing directions as written on the stripper you are using. Lastly, I would wait 24 hours before re-examining the surface to see if you are happy with the results. Then, I would sponge it with Acetone and let dry again for 4 hours. Then, sweep it vigorously to remove all dust residues. After that, do whatever you choose as far as sealer goes according to the manufactures instructions. This was a tough one to comment on because I think you should get a professional to do this safely and properly the first time.

We recently installed honed green deoli in our bath and floors. 511 impergnator was then applied to seal the stone. The colors have changed dramatically. The honed finish is now dulled and the silvery shine is gone and many brown hues have appeared. Some of the “ostrich” markings that dotted the tiles are even gone. Can you tell us whats happened and is there anything we can do other than removal.

Thanks, Joe

Hello Joe,

The Green Deoli is a slate from India as I am sure you know. What you are describing is usually caused by the moisture in the mortar under the slate which is trying to leach our though the slate surface. I don’t believe that the sealer is the directly the cause but it is inhibiting the ‘evaporation’ of the moisture.

Most slates are a composition of muscovite, quartz, illite and some biotite, chlorite, hematite, and pyrite. That is a lot of stuff and they each have different absorption qualities. The evaporation is not a simple homogeneous wet-to-dry look transition and for this reason many choose not to seal slate at all.

I believe the setting material moisture is fighting to evaporate and the sealer is inhibiting it. This could take months to change back to the original colors but it should do so. You could try washing the floor with acetone to remove some of the sealer, but I would recommend hiring a professional to do so. The best solution is to patiently wait.

Think about this. If you could actually permanently change the look of natural stone as you described, you should patent the process.

Best wishes,
Tom Cordova

Hi,

I’m in the process of redoing a fireplace, and am trying to figure out which natural stone to use. The fireplace is a wood burning unit. We plan on using a 6-8? surround with the hearth. I need something that is durable. I’ve ruled soapstone out because of the green veins that through the stone. I want to use a honed black granite, but my husband wants to use slate. He likes the rustic look of the stone, but I’m afraid that it looks too blue. Everyone that I have spoken with tells me that it scratches very easy, and that I’d be disappointed with it in the long run.

What’s your advice for someone looking for a produce that is durable, easy to keep clean, and will give years of lasting satisfaction? I’ll look forward to your input, and appreciate your time, Melanie

Hello Melanie,

Slate is a nice rustic option, but given your concern with long durability, you should consider dark granite. You say you want a honed surface I strongly recommend dark granite and be sure to apply a good sealer. However, I do not recommend absolute black granite (honed) because it just shows too much dirt and it is hard to keep totally clean (eg. finger prints).

There are so many colors to choose that you should just take a look at a lot of colors and see what goes best with your decor and taste. I recommend going to www.GraniteStock.com to search from hundreds of granite colors. You can search by color (brown, black, green) and then see a swatch of the one you like. You can also see if a supplier is listed in your area that has it in stock so that you can look at the full size slab.

Best wishes,
Tom Cordova

How do I remove a grout nightmare from my very pourous Indian, multi-coloured, un-sealed, slate tile? The genius who installed it, left the gour over-night and now my floor is wrecked!!!!! Help Please!

Adrienne

Hello Adrienne,

You need to acid wash the floor. There are several grout haze cleaning products sold at your local HomeDepot, Lowes or Ceramic Tile store but they all rely on three active chemicals. Phosphoric Acid, Sulfamic Acid or Amonia-bifloride. I mention this because you should try a “grout haze remover” first. However, it might not be strong enough to do your messy job. In which case, you need to go with a potent solution. For a very potent product, search for a “concrete acid etching product”. The product used when preparing concrete for painting or staining. This is strong phosphoric acid and may even have some ammonia bi-floride in it. Test it in a small area for desired results.

Note, these strong products love to eat calcium carbonate base materials such as marble and limestone. Slate is a different composition so you will not have the same detrimental etching results as marble. Still, discoloration may occur so if you go with the heavy duty solution, test it first. ear gloves and protect your eyes as well.

Best wishes,
Tom Cordova