Last winter i took a look into the attic and noticed black stains and water marks on a portion of the sheathing material.
Black stains on plywood in attic.
Black mold in attics.
First let s look at the source.
This can be caused by the action of fungal growth and molds and the affect they have on the tannins in the wood.
While the black stains are either mould or just black dust from attic insulation settled on the.
You can remove small amounts of mold covering 10 square feet or less of attic sheathing yourself but if the mold growth covers more than 10 square feet you should contact a.
This summer i cleaned the portion of the black stain with a dry mop as much as i could reach from the hatch opening.
When moisture condenses on plywood roof sheathing repeatedly or continuously the wood will turn black.
The following picture is of a long standing moisture condition in an attic where much of the roof sheathing has turned black.
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.
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.
If the wood is soft if it s easily imprinted when you push on it it s probably rotten.