Roof Sheathing Mold

A close examination of the photo above reveals large amounts of mold on the underside of the roof sheathing.

Roof sheathing mold.

This phenomenon occurs in vented attics and is more common in new homes than old homes. Generally tearing off a roof and roof sheathing and perhaps roof framing to remove mold would not be sensible nor cost justified. The presence of mold in your attic is often the result of poor ventilation insufficient insulation moisture from a roof leak or improper venting from your bathrooms or kitchen. Mold on the underside of roof sheathing is also very common.

Increasingly homeowners in the pacific northwest are noticing mold on the underside of their roof sheathing. This occurs when the temperature of the sheathing drops below the dew point creating a thin layer of moisture on the substrate. 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. What caused the mold and why did it thrive in this attic space.

In the vast majority of cases the mold growth is caused by condensation. Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest. The insulation was improperly installed over the soffit vents blocking air from entering the attic. Combine 1 2 cup chlorine bleach with.

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.