Black Spots On Plywood In Attic

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.

Black spots on plywood in attic.

The mold itself may have a cottony texture but can also be velvety leathery or. Mold usually causes a musty odor and may cause staining that may be black brown gray white yellow or green. 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. This can be caused by the action of fungal growth and molds and the affect they have on the tannins in the wood.

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. Black mold in attics. After several years of this there may be. Without proper ventilation in the attic high heat and humidity can build up which leads to moisture from a different source.

Walls that are improperly insulated may develop mold because they will absorb moisture from outside. Roof leakage can often be seen as dark black stains concentrated and radiating out from one or more individual locations. I did some investigating this august and sure enough i noticed a few black mold spots on the inside of the plywood. 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.

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 following picture is of a long standing moisture condition in an attic where much of the roof sheathing has turned black. It usually appears greenish black and streaky. 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.

When moisture condenses on plywood roof sheathing repeatedly or continuously the wood will turn black. If the dark surface of the wood smudges it could be mold. If the wood is soft if it s easily imprinted when you push on it it s probably rotten.