can I pebble dash over a previously rendered and painted wall?

The rendering has blown in parts so I'm assuming I have to knock this out and fill with mortar also the painted coating on the surface appears to be very thick a bit rubbery! this in parts is in very bad condition due to having to remove a lot of the dreaded IVY! The ivy removed can I render over this badly damaged surface? Does anyone know what a mesh is I read somewhere that you can put this on the wall instead of having to score the wall to give it a key? Thank you in hope and anticipation.