We've been in our newbuild (2017) a while and wanted to redecorate and change the colour in one of the rooms.
We cleaned the walls (drywall/plasterboard that still has the original builders' paint on it) down with sugarsoap etc, and let it dry and started painting using a normal water-based can of Dulux. The walls are dry, there's no damp and the RH is fine.
However when we started rolling into the existing paint, there were one or two places where the existing paint started to bubble and some even came away when I rolled over it using the roller (the photo is what happened).
I guess this is because the original paint that was put on there by the builders is either permeable or they didn't put down a layer of plasterboard sealant. At the moment, I am just spot filling these and overpainting, but I have several rooms to do and don't want to have to spot fill these as well.
Is there any way to seal the paint on the existing walls to stop it doing this, or do I have to completely strip all the existing paint off, and apply sealant, then repaint it again? Having to do that second option is pretty daunting especially as we have several rooms to do - and we also wanted to wall paper a part to, but are afraid that this will screw up as well.
Any recommendations on what I could use to fix this would be appreciated.