Black Spots On Plywood In Attic

The following picture is of a long standing moisture condition in an attic where much of the roof sheathing has turned black.

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. 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. Roof leakage can often be seen as dark black stains concentrated and radiating out from one or more individual locations. 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.

Walls that are improperly insulated may develop mold because they will absorb moisture from outside. I did some investigating this august and sure enough i noticed a few black mold spots on the inside of the plywood. Black mold in attics. This can be caused by the action of fungal growth and molds and the affect they have on the tannins in the wood.

Without proper ventilation in the attic high heat and humidity can build up which leads to moisture from a different source. When moisture condenses on plywood roof sheathing repeatedly or continuously the wood will turn black. It usually appears greenish black and streaky. Mold usually causes a musty odor and may cause staining that may be black brown gray white yellow or green.

If the dark surface of the wood smudges it could be mold. These are commonly seen underneath roof vents plumbing stacks vent hoods. If the wood is soft if it s easily imprinted when you push on it it s probably rotten. If you re not sure what you re looking for here s a picture of mold in an attic.

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. After several years of this there may be. The mold itself may have a cottony texture but can also be velvety leathery or.