I have black mold forming under the roof sheeting and on rafters in attic. I have a ridge vent as well as soffet vents on both sides. You can easily look down between the rafters and see daylite. What is causing this and how do i get rid of it.
If you have mold, then there is water intrusion causing it. We don’t have your roof on hand to look at–but either the water is coming through the roof or through the vents. If you have mold forming directly on your vapor barrier, there may also be condensation issues relating to temperature, humidity and an inadequate R value which a construction engineer would need to address.
Moisture incursion is happening somehow. So first you have to remove the water source so that it stays dry; you need to kill the existing mold. Once you make the environment no longer hospitable to mold, spores from the ambient out door air count will not be able to gain a foothold on your property.