I have a roof leak that someone told me is from condensation. Will a roof coating stop this?

Unfortunately, no. If you experience roof leaks when it doesn’t rain you likely are dealing with a roof condensation issue. This occurs when moist damp air (inside) hits a cold surface at the “dew point” temperature, such as your roof, and condenses. Potentially you can change the interior temperature at the ceiling enough by ceiling fans that reverse air flow in winter. Remember, hot air rises. Mixing it with cooler air at floor level sometimes can be enough to disrupt the process and save you some heating costs as well. Otherwise under roof insulation and/or vents are required.