Attic Sheathing Black

Condensation determining the cause of attic mold.

Attic sheathing black.

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. The mold itself may have a cottony texture but can also be velvety leathery or. I have surface mold on the sheathing in my 1982 vintage 12 6 pitched attic. 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 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. Uniform black mold growth on attic sheathing.

In many cases the continued wetting of the sheathing will cause it to rot but that may take several years or decades depending on the attic ventilation. Attic mold cleaner attic mold removal how to clean attic mold how attic mold gets there in the first place and what to do to help prevent attic mold. I m aware of the cause poorly vented bathroom fans and not well sealed fan fixtures lights wires etc. The other two possibilities for the stains.

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. Mold usually causes a musty odor and may cause staining that may be black brown gray white yellow or green. Despite what your roofer would like you to believe roof leaks rarely cause significant mold problems.

The following picture is of a long standing moisture condition in an attic where much of the roof sheathing has turned black. White and green fuzzy growth on osb sheathing.