Pics inside its definitely microbial growth.
Black spots on plywood in 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.
Attic moisture and poor ventilation are the causes.
Without proper ventilation in the attic high heat and humidity can build up which leads to moisture from a different source.
If the wood is soft if it s easily imprinted when you push on it it s probably rotten.
The variety i see most often is fuzzy green when active and goes black like that when dormant or dead.
Nails collect frost when the weather conditions and rh are right.
Call it microbial mildew or mold it really doesn t matter.
Uninsulated attic hatches are a common spot where heated air escapes into an attic.
After several years of this there may be.
Mold usually causes a musty odor and may cause staining that may be black brown gray white yellow or green.
Black stains in attic.
Black mold in attics.
Walls that are improperly insulated may develop mold because they will absorb moisture from outside.
That is a stain caused by mold mould.
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.
If the dark surface of the wood smudges it could be mold.
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.
When the attic has been damp or wet there might be a more serious problem with aspergillus sp.
You have something growing on the surface of the wood caused by excess moisture.
The mold itself may have a cottony texture but can also be velvety leathery or.
If the wood is solid it s probably fine.
It s probably just darkness that comes from the wood being repeatedly wetted and dried from frost forming melting and drying.
I did some investigating this august and sure enough i noticed a few black mold spots on the inside of the plywood.
Last winter i took a look into the attic and noticed black stains and water marks.
The new roof doesn t help much most of the moist air is likely coming up from below.
