Evaluating a building to control moisture and water damage is a painstaking process, but we have found the consistently best option for insulating the roof and reducing condensation and water damage is closed cell spray foam. Closed cell spray foam is so resistant to heat loss that the investment in quality insulation will pay for itself.
Proper analysis and diagnosis is key to solving a moisture related problem before it can lead to a toxic mold issue. There are many variables, but in general the rule of thumb is the house leaks warm humidified air into the attic. And before the ventilation can remove the humidified air, it stagnates, and sweats on the coldest surface first, typically the north facing side. Seasons of this activity occur, and the inevitable result is mold spore growth.
Spray foam prevents this by insulating the building properly. Since it is rigid and inorganic, it isn’t affected by mold itself and stays firmly in place for years, unlike traditional insulation.