You did not say what material the unlevel floor is. If plywood, sand it with a floor sander. If concrete, there are leveling compounds on the market, but they only work wall-to-wall (or barrier-to-wall). They pour on with a soup-like consistency, gravity does the leveling, and then hardens to a very tough, smooth finish.

It's my understanding that self-levelling concrete can be poured onto plywood. Is that not right?

update: I realize what you are saying. That the idea for ceramic tile is to make a floating floor to allow plywood expansion. but without that space between wall and plywood (which would be filled with a leveller), you no longer have a floating floor.

[This message has been edited by girldog (edited February 22, 2001).]

I have related question on this topic. We are renovating a room in an addition to a 60-year old house. The floor has old tile and its slopes toward the rear corner. Ideally I would like to take the tiles up and pour leveling compound over the concrete, but I am concerned about possible asbestos exposure. Would it be possible to prime the existing floor and then putting the leveling compound down? Or will this just not work? What would the alternative be?

vincef & chrisnlynn - Are your floors uneven because of changes in the floor joist or slab? Before going to the effort of leveling compound, make sure what's under is stable.

As for the asbestos tiles, the general rule is that unless you sand, etc., asbestos should not be a problem. Asbestos is a danger as a dust. Sanding or grinding the tiles would create dust as would (very slowly) wearing the tiles out by walking,etc. on them. With the asbestos glued into the tile, you can pry the tiles up.