Black Spots On Plywood In Attic

Walls that are improperly insulated may develop mold because they will absorb moisture from outside.

Black spots on plywood in attic.

If the wood is soft if it s easily imprinted when you push on it it s probably rotten. In the attic the most common places to find black mold are the places where water is likely to be a problem. This can be caused by the action of fungal growth and molds and the affect they have on the tannins in the wood. In old houses you ll usually see some spots that are stained dark or black where there was a roof leak at some point in time which was repaired but the stain remains.

In this photo of very dark mold in an attic in a wet attic mold which we found to be brown in the microscope looked black on the plywood. It usually appears greenish black and streaky. However there are many different types of mold so if the mold in your attic looks different that does not mean you don t have a problem or don t need to worry about it or take action. Roof leakage can often be seen as dark black stains concentrated and radiating out from one or more individual locations.

If you re not sure what you re looking for here s a picture of mold in an attic. These are commonly seen underneath roof vents plumbing stacks vent hoods. If the dark surface of the wood smudges it could be mold. Based on the reading i ve done on this site i have learned that the double stud wall system can cause condensation problems on the inside of the plywood sheathing.

The black attic mold shown here confirms that this attic had a serious venting and moisture problem including moisture from sources lower in the building. Black mold in attics. The following picture is of a long standing moisture condition in an attic where much of the roof sheathing has turned black. This latter phenomenon occurs when the house is too humid and the warm moist air seeps into the attic where it condenses and freezes on cold attic areas.

Without proper ventilation in the attic high heat and humidity can build up which leads to moisture from a different source. After several years of this there may be. When moisture condenses on plywood roof sheathing repeatedly or continuously the wood will turn black.