VENTILATION
Attics and crawl spaces are the predominant areas requiring ventilation. In both places it is necessary to have good distribution of air movement over the entire area.
Attic ventilation is essential. Without it, moisture that moves through the ceiling will be trapped in the attic because most roofing materials prevent moisture from escaping. Basically, the idea of cold-side venting is to relieve the vapor pressure in the attic by providing a vent to the outside air, which usually has a lower vapor-pressure.
Ventilate the attic with inlet vents distributed along the eave and with the outlet vents near the ridge. You’ll get the best results when the ventilation is uniformly distributed along the roof and is equally divided between the high and low. Warm air in the attic rises and escapes through the ridge vents: cooler outside air enters at the eaves