How do you fix a wall that has latex paint over oil based?

I recently asked ';Why does my paint still stick %26amp; come off the wall so easily?? I painted 2 rooms about 6 months ago with latex wall paint, I used primer first, but when I put a piece of furniture near the wall or hang something, the paint sticks to it and comes off the wall. What did I do wrong, and how can I avoid this happening again -- I still have 4 more rooms to paint!''


I used Kilz Primer %26amp; Kilz latex paint with an eggshell finish.





Someone suggested that maybe the old paint was oil based, so while I was waiting for more answers, I looked up how to tell oil based from latex (use finger nail polish remover, if it comes off it is latex, if not it is oil), after doing this I came to the conclusion that the old paint was oil based, so is there anything I can do for the rooms I already painted with primer %26amp; latex paint so that the paint does not continue to come off. And what do I do to prevent this with the other 4 rooms I am going to paint?How do you fix a wall that has latex paint over oil based?
I don't know what to tell you about the rooms you already painted. But, for the rest of the rooms, you have to sand the surface of the oil-based paint to give the primer something to stick to. Cured oil-based paint is not porous at all. So, you have to roughen up the surface to form small ridges that the primer sinks into to stick. The latex paint then sticks to the primer.

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