It is generally not recommended to install slate tiles directly over sheet vinyl flooring. Slate tiles require a stable and level surface for proper installation, and the flexibility and cushioning of sheet vinyl can lead to issues such as cracking or unevenness in the slate tiles over time.
For a successful slate tile installation, it is best to remove the sheet vinyl flooring before proceeding. This involves stripping the vinyl, adhesive, and any other underlayment materials down to the subfloor. Once the subfloor is exposed, you can assess its condition and make any necessary repairs or preparations before installing the slate tiles.
It's important to note that proper installation practices can vary depending on the specific circumstances and the recommendations of the manufacturer. It is always a good idea to consult with a professional installer or follow the specific guidelines provided by the slate tile manufacturer for the best results.