What it is: Unsealed openings let warm house air bypass into the attic at penetrations and top plates.
Why it matters
Air bypasses carry heat and moisture into the attic, wasting energy and feeding ice dams and frost.
Why it's common in Bloomington
Attic bypasses are a primary driver of ice dams on Bloomington homes during snowy winters.
Signs to watch for
- frost or staining around ceiling penetrations
- dirty insulation at leak paths
- warm spots on the roof in snow
What we check during the inspection
The inspector looks for bypass evidence such as frost, staining, and disturbed insulation in the attic.
How it's typically corrected
A contractor air-seals the penetrations and top plates before adding insulation.
Concerned about attic bypass air leaks in a home you're buying or selling? Get a free instant quote and we'll evaluate it as part of a full inspection.