There's an old epoxy coating in our workshop that has seen better days, some of it flaking, some rock solid. I'd rather not spend days grinding if I don't have to.
It comes down to how well the existing coating is still bonded, not its age. A quick adhesion check, a pull test or even a firm scrape and tap across the floor, will tell you whether the old layer is sound enough to build on or is already letting go in places. Where it is well stuck, abrading it to a matt, keyed surface and removing all contamination is often enough for a new system to grip. Where it is flaking, hollow or soaked with oils, taking it back is the more reliable path, and the same goes for tiles that drum or have loose grout. Since the right call really depends on what your test shows, get in touch and the technical team can talk it through with you.
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