An air conditioner in a home with improper attic ventilation must work overtime to keep the inside air cool particularly in the upper levels.
Mold due to improper ventilation of attic.
A humid environment is the ideal place for mold or mildew to grow.
In the winter months the cold air in the attic meets with the rising moist warm air from below caused by things like cooking heating and showering and creates condensation.
For example if a house has poor attic ventilation but the ceiling is well air sealed and the interior of the home has excellent ventilation mold growth will not likely occur.
Mold that grows on the underside of roof sheathing due to ideal mold growth conditions being present.
All this moisture will rise up into the attic if there are pathways for airflow.
Since warm air rises if it comes into contact with the cold attic sheathing then condensation occurs.
Yet many attics with ventilation far superior to the code requirements suffer from mold issues.
Attic ventilation is a two part process.
Stains around nails are not mold growth but are due to the chemical reaction between wet iron and tannins in the wood.
First air enters through the soffit vents.
Attic mold can happen in warm or cold weather.
Look for signs of mold growth such as black white or brown spots appearing on walls or a musty odor.
Nope venting an attic is actually pretty hard here s how ventilation is supposed to work.
Poor ventilation can lead to mold growth.
Mold can damage items in attic storage and cause respiratory problems for residents.
Mold on the underside of roof sheathing is also very common.
If one of these factors is operating poorly an attic might avoid mold growth by succeeding well in the other factor.
Improper roof ventilation and attic insulation may seem like small issues but they can actually lead to very expensive repairs and unnecessarily high utility bills.
Even with proper ventilation your air should not be vented directly into an attic.
If you combine moisture with restricted air circulation you will create a humid and moist environment the ideal environment for mold to grow and thrive.
When an attic is stuffy that indicates you have a ventilation problem which often results in mold problems.
Unfortunately improper installation or choosing the wrong kind of insulation causes moisture from the lower levels of the home to rise and get trapped in the attic.
The opposite is true but too a lesser extent.
The presence of mold in your attic is often the result of poor ventilation insufficient insulation moisture from a roof leak or improper venting from your bathrooms or kitchen.
If you re layering insulation atop other insulation don t use the kind that has kraft face finish i e paper or foil backing.
This moisture feeds mold growth.
Frost buildup on the underside of the roof sheathing in winter when it s cold enough outside water vapor in an attic with improper ventilation can freeze on the underside of your roof.
And many homes with terrible attic ventilation are completely mold free.