The source of the attic moisture is usually indoor air that enters the attic through ceiling cracks.
Roof is damp in attic.
Water found in these places is commonly caused by condensation in the attic.
This occurs when the temperature of the sheathing drops below the dew point creating a thin layer of moisture on the substrate.
Moisture frost and ice buildup on roofing nails.
Common causes of condensation in the attic.
If attic air is humid and roof sheathing is cold condensation or frost can accumulate on the underside of the sheathing.
If you suspect you have moisture problems in your attic check for the following indications of excess moisture in the attic.
Most people assume this is caused by a leaking roof but that might not be the source.
And to make matters worse these holes are not easily identified unless it s raining.
In the vast majority of cases the mold growth is caused by condensation.
Water or drip marks scattered on the attic floor.
Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest.
There are dozens of things that can cause condensation buildups in the attic one of which is a leaking roof.
A roof timbers within an attic can become damp from two sources.
Even a small pin head sized hole can send gallons of water pouring into your attic over the course of a couple months.
Moist or wet insulation.
Finding water damage on the wall or ceiling is worrying for any homeowner.
The cause depends on whether you have an unconditioned attic or a conditioned attic.
Fixing this issue can be less costly than replacing a roof but it should be addressed as soon as possible.
Buckled or damaged roof sheathing.