You need a minimum 1" of subfloor under tile. You cannot tile over the adhesive for a number of reasons. The adhesive needs to be as even as you can get it. Spaces(unevenness) create bounce and bounce will kill a ceramic tile floor. Adhesive is probably asphalt based. Older tile was a combination of vinyl and asbestos. You do not want to start banging, sanding or causing dust from this product. Pull up the sheet vinyl and screw and glue down a layer of 5/8" plywood. On top of that I would put a cement backer product(1/2 or 1/4") that was thinsetted and nailed /screwed down. If floor is level, you can tile. If not, level the floor. Ron

What is the size thickness and material of the old and new tile? "floating" has too many other meanings relative to flooring to be used to describe decoupling ceramic tile from a wood structure. Historically this was done with a thick mortar bed reinforced with metal mesh that required the floor framing to be lower in the tiled areas. Waterproofing or building paper placed below the "mud" bed provided the decoupling. Glued drywall underlayment was a cheaper way of doing the same thing using organic adhesive which suggests it was a DIY job. I suspect it survived because the floor did not get very wet. I can't think of a reason a professional tile setter would risk not using Ditra or a cement backer board (or both) for your floor.

Cheap tiles will chip easily, but only break apart if the substrate they're on is "iffy". Being concrete, it's probably the thinset layer. It might come off relatively easily if it was mixed improperly. Too much water could make it softer. If you don't have that luck, it will be tedious and dusty to get it flat enough so the two rooms are on the same plane. Ron

I paid about $2K to have an asbestos removal company take up my kitchen and basement tile floors. They did it correctly, hazmat suits, air blowing outside the house, rooms sealed off, etc. But this powder room was forgotten! Someone shut the door and they didn't see it! So, now I've got 16 square feet of presumed asbestos-containing floor tile (don't know since this particular tile wasn't tested) either to cover up or remove. My carpenter doesn't think it's worth calling in the asbestos removal people, and in my state, a homeowner can remove non-friable suspected asbestos-containing flooring up to 100 square feet. I'd like to cover it up. All the EPA websites say cover up asbestos tile. It's not dangerous if it's not friable (crumbling) and my tile is not. The underlayment for Click will add more height to the powder room floor. There's a silvery foam type sold by Farbo (it's 1/8" at least), and whisper wool underlayment that's 1/8" thick. So my powder room floors would be 3/8" higher than my kitchen floor. Will this look bad? Will the underlayment be enough to "hide" the uneven floor caused by the missing pieces of white tile? Or will I need to fill them in/even out the floor with some leveling or patching product? I looked up t-moldings and reducer moldings -- not the look I was hoping for, but I can live with it if I have to. I understand Farbo no longer sells transition moldings. I was hoping I could get the Marmoleum and the wood floor to abut each other at the same height, but I'm assuming this isn't possible with Click? Does anyone know? Does anyone have Click installed adjacent to a wood floor without an expansion gap?