HardiPlank is pre-primed in most cases so priming isn’t needed for the application of a quality paint. All paints have a minimum thickness for maximum performance, this is listed on the paint can or by the manufacture as a mill thickness. It is hard to get the mill thickness with 1 coat and still look good. 2 coats would be better in this situation.
Contractors want to spray on one coat of paint on my hardiplank. Is one coat enough?