[libbybuddy]

I would like to put ceramic or porcelein tile on my concrete family room floor. I've removed the tile and about 90% of the mastic. Does 100% of the mastic need to be removed from the whole floor before thinset can be used to start tiling. I'm getting mighty discouraged as the mastic is not easy to remove. Is a floor leveler a good idea? I found the citrus based mastic remover much easier to use than the bean goo, FYI. Thanks for any help.

 

[JazMan]

You forgot to say what type of adhesive remains on your floor. What type of tiles did you remove? How old were they? What color is the glue? Does it have ridges or does it look like it was applied by brush or roller? Do not use chemicals, the citrus stuff should be OK, since you will be rising after. You should be able to remove most of the glue using a razor scrapper tools. It's called a wallpaper scrapper, looks like this; http://www.core-industrial.com/manage/gallery/tSCRAPERS%20(Small).jpg Remove until you have only a film of adhesive but can see concrete too. (It is concrete right?)

Once done, check for flatness and choose a thinset mortar that is compatible with the old adhesive. Answer the questions so we can try to identify it.

Jaz

 

[libbybuddy]

I removed asbestos tiles, original to the house built in 1967. The glue is a black mastic which appears to be troweled on due to some semi-circular patterns in it. It is thicker in some spots than others. I have glops left which perhaps were the tops of some of the ridges. Thanks for any help you can give.

 

[poppameth]

That's not mastic. That's cutback. It's probably loaded with asbestos as well. For most types of flooring you need to encapsulate it at the very least. For ceramic I wouldn't trust anything other than complete removal.

 

[JazMan]

That's poppy-cock! :huh:

Cut-back is mastic, but that makes no difference. Not all black asphalt-based adhesive contains asbestos, but assume that it does. There are dozens of modified thinset mortars that are compatible with "cut-back", says so right on the bag too. :thumbsup:

Go ahead and cut the black stuff with the scrapper, keep it damp so you do not make dust which might release any fibers. Once you see the gray-beige of the concrete you can start the installation. Be sure to follow directions and among other things get a good mechanical bond by "burning", flat troweling the thinset to the floor before going back with more thinset troweled with the proper notched trowel.

Jaz