Methods of Ventilation

The primary purpose of ventilation is to replace the moist air in the ceiling cavity with drier air from outdoors.

As warm, wet air tends to rise, a vent placed in the soffit or at the lower end of a roof will normally operate as an intake vent and a vent at the apex as an exhaust vent, but wind direction can reverse this relationship. Gable-end vents or vents aligned horizontally will act as an intake or exhaust depending on the wind direction.