Power cleaning using spray equipment such as media blasting using baking soda or dry ice is very effective for these surfaces.
Mold in roof rafters.
Attic mold left unchecked can grow and lead to structural deterioration of attic sheathing and roof structural elements.
This occurs when the temperature of the sheathing drops below the dew point creating a thin layer of moisture on the substrate.
In the vast majority of cases the mold growth is caused by condensation.
Systemic growth occurs when the roof leak causes enough moisture buildup in the attic to cause mold growth throughout the entire area.
Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest.
And eventually cause wood rot and reducing the life of your roof.
There s an underlying moisture issue that needs to be resolved because mold requires moisture to grow and spread.
How to remove mold from your attic.
Clean up the area.
Perhaps you use it for storage.
Mold problems are indications of water problems.
Re roofing with lining lining papers sarking roofing felt can cause severe mold growth and rot due to reduced ventilation.
At some point you will probably need to go to your attic for something.
Cleaning mold from irregular or hard to reach wood surfaces media blasting.
If mold needs to be removed from a roof deck through which roofing nails penetrate hand wiping is not feasible.
When removing mold from your attic your first concern should be protecting the rest of your home from it.
Generally tearing off a roof and roof sheathing and perhaps roof framing to remove mold would not be sensible nor cost justified.
Water and mold problems in the attic can deteriorate wood in the roof sheathing joists etc.
Seal off the area.
Examine the insulation along your rafters.
Mold growth provided it is not just cosmetic mold which can simply be left alone can be cleaned from wood surfaces by blasting scrubbing or even simple surface wiping depending on the surface accessibility and smoothness.
If the insulation has been affected by the mold remove it in thick trash bags and replace it with new insulation after you complete your mold remediation.