My floor is already painted, would I be able to apply Resincoat paint on top of it?

We would always recommend that you first remove any and all existing finishes/coats of paint that currently exist, rather than applying a resin-based paint over the top. Ideally by grinding or shot blasting the surface.

If this is not possible, and the existing coating is very well bonded; please ensure that it's dry, clean and dust-free before abrading to create a mechanical key prior to coating.