I live in a single-level ranch style house but on a concrete pad. I am re-tiling the kitchen floor. Upon removing the old tile, I discovered a 15 lb. felt pad had been glued to the floor; on top of this pad was thin set; then the tile. I live in Bakersfield, CA which is a dry and arrid climate.
This Site Might Help You. RE: Do I need a vapor barrier when installing ceramic floor tile? I live in a single-level ranch style house but on a concrete pad. I am re-tiling the kitchen floor. Upon removing the old tile, I discovered a 15 lb. felt pad had been glued to the floor; on top of this pad was thin set; then the tile. I live in Bakersfield, CA which is a dry and arrid climate.
YIKES!! Even in the High Desert of California, there is moisture underground. But, getting to your question: a) If your pad was poured over a vapor barrier (visqueen, typically), you do not need to add anything new *as a vapor barrier*. b) It cannot hurt to install a sealer on top of the concrete before you install new tile in any case. That will reduce the dusting in any case. c) But I am thinking that the felt paper you found was installed as a strain-relief rather than a vapor-barrier. It allows the tile to move differently than the concrete slab. This becomes important if there are extreme changes in outside temperature - which penetrates the edges of the slab and varies with the time-of-day - with relatively constant temperature inside. If the tile is bonded directly to the concrete as those temperature changes take place it will begin to spall and separate - not good as even a few fractions of an inch of difference will be enough to break the bond between the tile and the concrete. Were it up to me, I would install a strain-relief (AKA underlayment) with the new tile. There are liquid applications (Laticrete) and sheet goods (Durock) which come to mind and are very effective as a bond-breaker yet give a solid, reliable surface to hold the tile. These are only two of many and are linked below.
No vapor barrier required but clean the cement floor and seal it. If not level use thin-set to level out. Don't forget to seal your grout and tiles if directed by the manufacturer. This has to be done annually. Avoid harsh detergents as they will yellow your tile and follow manufacturer's directions on cleaning.
As long as it's not ceramic tiles, if so, I'd tear off the tiles. If it's linoleum, make sure you have a good subflooring and knock yourself out! Fallow the recommendations of the spacing around the walls AND take the time to bring in your flooring and let it in the room it'll be used for at least 24 hrs to dilate with the room's temperature and humidity. Don't pile all the packs in one corner, they need to breathe.
