Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest.
Roof sheathing mold.
What caused the mold and why did it thrive in this attic space.
Attic spaces are one of the most common places in a home for mold to be found growing.
A close examination of the photo above reveals large amounts of mold on the underside of the roof sheathing.
This phenomenon occurs in vented attics and is more common in new homes than old homes.
Increasingly homeowners in the pacific northwest are noticing mold on the underside of their roof sheathing.
The insulation was improperly installed over the soffit vents blocking air from entering the attic.
Combine 1 2 cup chlorine bleach with.
In the vast majority of cases the mold growth is caused by condensation.
One puzzling aspect of the phenomenon is that the mold is found in well built homes that comply with all relevant building codes.
Because wood is porous it may be difficult to remove the mold stains from sheathing but you can kill the mold by cleaning the sheathing with bleach and water.
This occurs when the temperature of the sheathing drops below the dew point creating a thin layer of moisture on the substrate.
Generally tearing off a roof and roof sheathing and perhaps roof framing to remove mold would not be sensible nor cost justified.
Mold on the underside of roof sheathing is also very common.