Black On Underside Of Roof Sheathing

Dark areas on the underside of roof sheathing can sometimes be tricky to diagnose.

Black on underside of roof sheathing.

Check other attic vents if present e g. These are commonly seen underneath roof vents plumbing stacks vent hoods and around chimneys. Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest. Quite a few attics that i have been in have dark splotches on the underside of the roof sheathing but not all are related to mold.

In our roof interior attic photo at left you can see antique roof framing along with black stains and probably some mold growth from a long history of roof leaks. The east gable wall is black the west gable wall is fine. Ridge vents roof vents gable vents and make sure they re unrestricted and properly installed. This can be caused by the action of fungal growth and molds and the affect they have on the tannins in the wood.

Mold that grows on the underside of roof sheathing due to ideal mold growth conditions being present. In the vast majority of cases the mold growth is caused by condensation. The following picture is of a long standing moisture condition in an attic where much of the roof sheathing has turned black. This occurs when the temperature of the sheathing drops below the dew point creating a thin layer of moisture on the substrate.

Even in this case in our opinion the reasons to remove and replace roof sheathing and framing would normally be based on the condition of the roof framing and sheathing not on the. Roof leakage can often be seen as dark black stains concentrated and radiating out from one or more individual locations. Mold on the underside of roof sheathing is also very common. Wood will discolor when dampened on a regular basis.

Mold growing on the sheathing in your attic is a serious problem that shouldn t be ignored. Mold on attic sheathing. Seeing some stains on the underside of the roof sheathing or framing may not be a cause for serious concern. When moisture condenses on plywood roof sheathing repeatedly or continuously the wood will turn black.

The roof was supposedly replaced two years ago. 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.