Alkalinity on the cement plaster imposes various types of issues to the water-based wall coatings. If the pH is more than 10, we should not be coating the wall ideally. In exterior conditions, if we leave the wall in its ambient weather conditions for 1.5 – 2 months, the curing of the cement will be improved. The pH of the wall too will come down making it fit for the application. For interior conditions, we need to provide a slightly prolonged duration like 3-5 months before which it can be coated.