How do I resolve blistering of paint on plaster?

Blistering can occur on plaster if you overcoat solvent-based paints such as gloss or eggshell with a conventional emulsion in an area that suffers from high levels of condensation. To resolve the problem, scrape back the blistered paint until you have a firm edge, feather lightly with abrasive paper and dust off. Now spot, prime and bring forward any bare areas with Dulux Primer Sealer, using Dulux Alkali Resisting Interior Wall Sealer on friable surfaces. Finally, repaint the surface using a thinned first coat of water-based Dulux Pentalite followed by one or two full coats.