Fixing Slate Floor Tiles Sealed Incorrectly

by MaryAnn
(Houston, TX, USA)

Question:
I recently had my slate installed by someone not very knowledgeable about the product. The slate was grouted then sealed, but now the grout is in the crevices and pours of the slate. How can I fix this problem? Can the slate be sanded down then resealed with a silicon penetrating sealant?

Answer:
Do not use a sander on slate tiles, it is not as simple as sanding them down, you will just ruin the tiles.

I presume that the not so knowledgeable person did not seal the slate tiles before he grouted & this has caused the staining of the slate.

Firstly I suggest you contact NTC http://www.ntc-stone.com/contact.html & ask them which product they recommend & is readily available in the USA that can rectify your problem, these guys are experts in this field & many others & will give you the correct method to rectify the problem.

Because you are in the USA, the products to rectify the problem will be different from that available in the UK.

I think they will tell you to do the following

1) Apply a product to remove the sealant on the
tiles

2) Clean the grout stains with a grout
residue remover (lots of scrubbing)

3) Re-seal the floor

You may find that you will not get the grout stains out 100% but it will look a million times better than it probably looks now

Perhaps you could send us a picture of a before & after?