How do you deal with powdery internal plastered surfaces?

Powdery and chalky surfaces are quite common in older properties that have been painted with distemper or white wash. You should completely remove these coatings by washing with warm water and a detergent solution. Rinse with clean water and change the water regularly. If the surface still remains slightly chalky, seal with Dulux Adhesion Promoting Interior Wall Primer prior to finishing.