HouseSymptoms field intelligence
Likely causes
Failure modes and building-physics mechanisms connected to the clues that support or weaken them.
cause 60ventilation-and-airflow 8roof-envelope 7building-structure 6drain-waste-vent 5appliance-connections 4domestic-water-supply 4exterior-wall-envelope 4cooling-and-air-conditioning 3foundation-and-ground 3insulation-and-air-barrier 3site-drainage 3space-heating 3electrical-distribution 2leak 2windows-and-doors 2
cause⌁
Disconnected bathroom exhaust duct
Humid exhaust air is released into an attic, ceiling or wall cavity.
cause⌁
Restricted dryer exhaust
Lint, crushing or excessive duct length reduces moisture removal.
cause⌁
High indoor humidity
Moisture generation exceeds removal for the current temperature and air exchange.
cause⌁
Low bedroom air exchange
Overnight moisture and contaminants accumulate faster than they are removed.
cause⌁
Soot deposition on a cold surface
Airborne particles collect preferentially at cold or high-airflow patterns.
cause⌁
Surface microbial growth
Moisture and available nutrients allow growth on or within a surface layer.
cause⌁
Unbalanced house pressure
Mechanical systems create pressure differences that move air and odors through unintended paths.
cause⌁
Duct pressure flexing
Thin sheet metal changes shape as system pressure changes.
