On this topic, something fundamental:
PVC tiles have never existed and do not exist.
In the past, tiles were used as ceramic wall coverings, which have been called "wall tiles" for many years.
The dangers of the installation method mentioned are that
a) on the one hand, there will be no locking between the substrate (the old covering) and the new PVC floor covering as a roll product; it cannot exist.
With unavoidable thermal changes in the room climate, the new covering will find its own path, it will slip and tend to form widespread bubbles due to foot traffic/use.
Well. Aesthetics are purely a matter of taste, but this has nothing to do with installation according to technical rules!
regarding b) It cannot be ruled out that within a short time—especially in areas with point loads (walkways, chair contact areas, etc.)—
brown spots will form on the surface of the covering, which will be due to plasticizer migration.
The solution to both problem areas consists of using a suitable, plasticizer-resistant dry adhesive between the old covering and the new one.
This also ensures locking of the new covering, which can be removed again after moving out of the apartment without damaging the old covering.
Height equalization can only be achieved by smoothing with a stable mineral leveling compound.
However, this cannot be applied on an old covering but must form a solid bond with the screed.
A solution here would be possible with a suitable transition profile, which, however, must be fastened on at least one side.
Otherwise, the profile will slip out of position during use, etc., and in the best case, a gap will form between the laminate and the new covering.
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Not every trade is fully suitable for the layperson!
If the professional rules are disregarded out of ignorance or lack of knowledge, one must live with the consequences.
Good success and a lucky decision: KlaRa
