I recently inspected a home with black mold in the attic, I am uncertain as to the cause. The attic had ridge vent the entier distance of attic, soffit vents continuous, the access was caulked shut, card board baffeles were installed in every truss bay and about 20 inches of blown in insulation was installed. My observations of defects were two; 1)The exhaust fan was only run up to the ridge vent (no positive connection) and was not insulated. 2)The blocking at the wall line betwen truss was installed verticaly and only about 1/4’ - 3/8’'was left as a gap. My only other observation is that the heat source is a mix of radiant floor and baseboard (both electric, not water) and no whole house fan, so there is no controled exchange of air. Any other thoughts???Thanks.
It says no positive connection of the attic fan and I am unsure what that means but, here is what I can tell you. If there is a whole house fan that is not vented completely to the outside that can cause it. Warm moist air meets a cold roof and it will condense (mold). Are you in a colder climate? Does the temperature get below 40 degrees? Was it cool in the attic or hot when you were there?