I think using egg shell on new plaster that is not quite dry may have caused this, especially if it wasn't given an undercoat designed for new plaster. I do not use egg shell any more after something similar happened in my newly plastered kitchen. After you have scraped away the flakie bits and lightly sandpapered it down use a good emulsion like Crown. . My builder suggested I open all my windows every day for at least 15 minutes to ensure a good flow of air to reduce any condensation from new plaster/paint, this has become a habit.

I painted some furniture in chalk paint however when i apply the wax and rub off i'm pulling off some paint too. Is there something i can do at this stage to stop that happening?

Hi Rowland, I actually tried to paint it one more time after sanding and applying zinsser and the rustins products and it seemed to have worked. Thanks for the reply and if it reoccurs I will look at the points you have written, hopefully I won't need to! On many of my other posts you recommended to use toupret, I had previously used polycell polyfilla. I wish I had taken your advice earliar, as the toupret was so much better to use as the areas that needed filling were large! Also the colour of it makes it easier to find when you sand it down later, I kept missing areas I used polyfilla. Thanks to everyone below for the advice, so happy I managed to paint the room after using the advice on this forum!

Sounds like traces of paste left on the wall. Were walls bare plaster? If so, they should be primed or use a bare plaster paint before the top coat. I'd sand down the wall, wash with sugar soap then clean water. When dry apply a primer and you should be ok.