Ok to apply new concrete surface on top of old painted concrete surface?

I have a concrete porch with an old, ugly, scratched up painted surface.


I would like to resurface with new concrete and then acid stain.





Will new concrete stick well to the painted concrete? Would I need a bonding adhesive first? Or perhaps some concrete resurfacer?





I prefer a new purer concrete surface for the acid stain. The old surface is just discolored/painted and would be a ton of work to make it look new.





Thank you.Ok to apply new concrete surface on top of old painted concrete surface?
New concrete won't bond to old concrete no matter what you do, that's why starter rods would be helpful (sort of like the concrete nails idea) You could just drill some holes in the concrete and glue bolts (like liquid nails or max bond) into the holes leaving the bolts sticking out like starter rods, depending on how thick your intended slab would be is how far they would be protruding out, make sure to leave any rod to sit at least 1 1/2'; below the surface of the new concrete.


If you intend you lay a slab thick enough for starters, if not just tile over the old concrete, scrap of most of the paint off as you can and use a rubber type setting compound.








%26gt;%26gt;%26gt;If bonding concrete really worked, why do people use expansion joint, you'd think they would just bond the concrete together and be done with it, BTW which you'll need to place around the boundries of the slab that's against any masonry%26lt;%26lt;Ok to apply new concrete surface on top of old painted concrete surface?
There are 2 types of concrete overlays, bonded and un-bonded.





A bonded overlay is when you apply a bonding agent to the existing slab and pour on top of that. This allows the two slabs to move in unison, and makes the topping slab more resistant to impact damage and spalling.





An un-bonded overlay is when a bond breaking agent (or layer of thin plastic) is applied in the same way. The benefits of this technique are that cracks in the bottom slab don't transmit directly into the new slab and it can move independently (like a ';floating'; floor system).





Whichever method is used, it must be consistent. Any part that bonds or fails to bond will cause the slab to crack or break.





I recommend that either be performed by a licensed contractor with overlay experience. This could be fairly easy to mess up without experience.





It might take more time to clean your existing slab to an acceptable level, but you are much more likely to have better results in the long run. And just imagine the cost of clean up and redoing it all over again.
the problem is, new concrete will not adhere to old concrete and eventually it will start to crack and fall apart and then it will look worse than before. how long this will take i dont know maybe only one season. the problem is the new concrete will not expand and contract in unison with the old concrete,again, causing it to crack. the only sure fire way to do this is to replace the entire porch with a new slab of concrete.
Hi,


You need to remove the old coatings %26amp; to help you should use a liquid bonding agent that gets applied to the old concrete. You didn't mention the thickness of the new application but 2 separate pours are never as strong as 1.
Not over smooth concrete.





The old should be Roughed up.





I would even consider driving a lot of concrete nails partially into the old, so that the new will stick.





A supplier may have a better way.





Don't just pour over the old.


It will flake off.
You need to call the concrete supplier and see if they have concrete with the correct plasticizers in it. The old surface should be roughed up with floor grinder. Don't go too thin as it will just crack.
The best thing to do is get the old concrete striped and ground smooth again. Your other option is to break up the old slab. You can't pore new concrete over old.