Painting new bathroom plasterboard

[Emmaghil]

I am painting our self build house myself, having an issue in the bathroom. The walls were plasterboarded and then taped and filled. The joiners used marine (blue) plasterboard at the shower. The shower cubicle has been tiled and I am painting the walls and ceiling. The problem is that the paint is peeling off the walls, particularly on the blue plasterboard. I tried scraping and then redoing it but same thing happening.
Should I have sealed it first? Worried that if I keep going it will peel with moisture from the shower.
Thank you

 

[dcdec]

Would have been better to tile all the marine board area. Zinsser gardz will seal it though. Don't use ordinary matt emulsion, use kitchen and bathroom, trade eggshell or if you have to silk (yuk).

 

[jerryhubbard]

The plasterboard should be primed first using primer. This gives the paint something to grab to.

 

[zarrahtracey]

Naturally, this will happened if we miss something that didn't exactly fit our wall. Here's something to avoid, try not to line up a sheet of drywall from a window or a door opening.