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.
Mold in attic roof.
If you have mold in the attic we recommend consulting with a mold removal specialist because.
Wooden beams and plywood may be affected and it can be difficult to remove all traces of mold from wooden surfaces.
Insulation is often affected.
This occurs when the temperature of the sheathing drops below the dew point creating a thin layer of moisture on the substrate.
Dryer exhaust vents kitchen exhaust fans and bathroom exhaust fans.
In the vast majority of cases the mold growth is caused by condensation.
Heating ventilation and air conditioning ducts may also.
Blocked or insufficient ventilation.
The most common cause of attic mold by far is blocked or insufficient ventilation.