Roof cuts and thermographic imaging can also detect moisture in addition to other strategies.
Roof boards damp.
Also look for a thin stream of water flowing down one of the rafters.
Follow the water uphill till the wood is no longer wet.
Cracking noises can sometimes be heard when walking on the roof during wintertime as a thin layer of ice breaks he adds.
Look for damp spots on the underside of your roof.
In the vast majority of cases the mold growth is caused by condensation.
Look for potential entry points like roof vents valleys loose nails and mark the area with chalk so you can examine the exterior of your roof after it quits raining.
It is never a good idea to install a roof over wet plywood or any type of roof sheathing.
This leads to the formation of damp spots on the surface of the roof.
The osb and in fact any wood panels must be allowed to dry completely depending on how wet the panels are this could be a few days before any roofing material is applied to avoid trapping moisture under the roof material that could cause edge swell and buckling.
Mold growth on attic roof sheathing is a common issue in cool climates such as the pacific northwest.
When this warm air reaches the spaces in the roofs it gets in contact with cold air and condenses.
Another leading cause of condensation in roofs is the use of wood burner cookers.
Such cookers often allow for the quick rise of moist air leaving behind the cold air.