In the vast majority of cases the mold growth is caused by condensation.
Mold in attic roof.
Heating ventilation and air conditioning ducts may also.
The photo at the left was identified as a toxic mold that probably should be removed although the ease of movement generally tearing off a roof and roof sheathing and perhaps roof framing to remove mold would not be sensible nor cost justified.
If you have mold in the attic we recommend consulting with a mold removal specialist because.
This occurs when the temperature of the sheathing drops below the dew point creating a thin layer of moisture on the substrate.
Insulation is often affected.
What causes attic mold.
Blocked or insufficient ventilation.
Improper exhausting of bathroom fans or dryer vents.
Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest.