I'm currently painting my hallway with flat (matt) emulsion paint. This is now the third coat I'm applying (decided to change the colour with the third). The problem I have is that after the paint has been on a few minutes, I get bubbles appearing. Not just the odd one, but quite a lot. There's areas of the wall that look like they've broken out in chicken-pox! The previous occupants had painted the walls with a silk-finish emulsion (I presume anyway) but I don't know what was under that. I wonder if there's some weird chemcial reaction going on. It doesn't seem to matter how many layers I apply, I still get the bubbles. Once the paint is dry, there are no surface changes. Anyone have any idea what is going on?