Tile on concrete flooring preparation

nanllyn

We just took up 50 year old vinyl tile off of our basement concrete floor. Under the tile was a black glue/adhesive that won't come off. We even used a commercial strength adhesive remover but it didn't help at all. We have scraped it until the floor is smooth but we didn't know if we needed to take the adhesive completely up.
We are wanting to paint the flooring with waterproofing paint/sealant. Then we will be tiling the flooring.
So our question is do we have to completely take up the adhesive? And after we "paint" the floor with the waterproofer then can we just grout over it and tile?
Also it is a basement floor but the house is almost 70 years old and does not have any settling cracks. So do we need a tile membrane to prevent the tiles from shifting and cracking?
Thanks so much for your help. We just want to do this correct the first time so we don't have to redo it.
Nancy

Bud Cline

Your first question should have been: Can we use a chemical to remove the existing adhesive in preparation for ceramic tile?

The answer would have been: "No", chemicals are bond-breakers when it comes to ceramic tile installations.

Your next question should have been: Can we paint our floor with a sealer prior to installing ceramic tiles?

The answer would have been: "No", sealers are known bond-breakers when it comes to installing ceramic tiles.

Your next question should have been: Do we have to remove all of the black vinyl tile adhesive residue in preparation for installing ceramic tiles?

The answer would have been: "No", there are thinset adhesive mortars available that can be used over "cutback" adhesive if the floor has not had chemical adhesive removers or sealers used on it.

So...at this point...why don't you divulge the name of the secret waterproofing sealer you intend to use and we'll see what that brings to the party?

If the floor is seventy years old now and has no cracks why would the tile crack and shift?

Yes, I can see that!