Inadequate ventilation or excessive moisture conditions in an attic can lead to the deterioration of the roof sheathing and premature failure of asphalt shingles. Frost on the nails penetrating the roof sheathing is indicative of excess moisture or improper ventilation. Another problem occurs when plumbing vent stacks terminate in the attic. Hazardous sewer gases and excessive moisture can accumulate. Verify that other vent pipes, including mechanical fans from the bathrooms and kitchen range hoods do not terminate in the attic as well.
Excess moisture can cause problems, such as rot or decay in the wood framing systems.
However, the inspector should be knowledgeable about the damages that termites or wood boring insects can cause and the signs to look for. High liability claims have occurred against inspectors, and significant damages awarded, despite any disclaimers to the contrary. Probe any suspect wood and recommend that a properly licensed or qualified pest control operator be consulted prior to closing. Closely observe all chimneys and note all defects. Look for loose mortar joints or signs of soot or smoke on masonry and metal chimneys.