Black On Underside Of Roof Sheathing

When moisture condenses on plywood roof sheathing repeatedly or continuously the wood will turn black.

Black on underside of roof sheathing.

Mold on attic sheathing. The following picture is of a long standing moisture condition in an attic where much of the roof sheathing has turned black. Mold on the underside of roof sheathing is also very common. Ridge vents roof vents gable vents and make sure they re unrestricted and properly installed.

The roof was supposedly replaced two years ago. 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. 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. Wood will discolor when dampened on a regular basis. Roof leakage can often be seen as dark black stains concentrated and radiating out from one or more individual locations. The east gable wall is black the west gable wall is fine.

This can be caused by the action of fungal growth and molds and the affect they have on the tannins in the wood. Dark areas on the underside of roof sheathing can sometimes be tricky to diagnose. These are commonly seen underneath roof vents plumbing stacks vent hoods and around chimneys. 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.

Seeing some stains on the underside of the roof sheathing or framing may not be a cause for serious concern. Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest. Does mold on attic sheathing have to be removed. 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.

It s not uncommon for wasp nests to restrict vent screens or for the plywood sheathing at the ridge to not be cut back sufficiently to allow the upper ridge vent to perform its intended purpose. Mold growing on the sheathing in your attic is a serious problem that shouldn t be ignored.