Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest.
Mold in attic roof.
In the vast majority of cases the mold growth is caused by condensation.
Blocked or insufficient ventilation.
Heating ventilation and air conditioning ducts may also.
If you have mold in the attic we recommend consulting with a mold removal specialist because.
The most common cause of attic mold by far is blocked or insufficient ventilation.
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.
What causes attic mold.
Dryer exhaust vents kitchen exhaust fans and bathroom exhaust fans.
Insulation is often affected.