Just moved into a house with a carpeted bathroom. After removing the carpeting, I found a badly chipped ceramic floor tile laid on top of vinyl tile. Removing the ceramic tile started to pull up the vinyl tile underneath. I suspect the vinyl tile contains asbestos. My question is can I just level out the chipped tile and lay down 1/4" backerboard just using thinset without nails as I do not want to disturb the tile underneath. I plan on installing a vinyl floor. Or...are there any other options?