I'll be painting a small bathroom next week where condensation is a big problem, the owner insists that he wants me to put oil-based eggshell on all walls. The paint is peeling back to bare plaster. Once I have made good the area by scraping and filling would I be able to mist coat the area with some emulsion then paint in oil eggshell or do I need to use an alkali resisting primer instead? Wouldn't the emulsion stop any reaction instead of the primer?