I had my driveway resin'd 5 years ago. Love it. I would just like it refreshed, colour change etc. Would I need the existing resin taken up first, or can it simply be overlaid?
The saying is, 'it's only as good as it's base'. If the surface is sound, it should be absolutely fine. Main things is that the surface is clean, dry and free from contaminants, loose etc. Resin bound will actually bond really well to an existing resin bound surface. I should note, that the overlay should be at least 18-20mm thick (for a driveway). As it will be an independent layer, it needs the correct depth for strength. Your contractor should be able to assess the existing surface, to see if it's suitable to overlay. Hope that helps.