One thing that is easily visible on pre-drywall inspections is attic ventilation. What you don’t want to see is suffocation – when attic venting is blocked.
Over the years attic ventilation has changed, and even improved. In fact, there is even a theory out there that subscribes to NO attic venting, based on the kinds of materials used to insulate the attic. But that is another story. One of the most effective forms of attic ventilation is called soffit and ridge venting. Intakes are provided for air to get into the attic space from the soffits under the gutters.
Another long, continuous vent is cut out of the ridge of the roof, and covered to prevent moisture,insects and animals from getting inside.
As air enters the soffit vent and warms it rises and convection draws it toward the top of the roof, for eventual discharge.The idea is to try to balance the amount of air coming in and going out. It is a passive system, but effective because it is pure physics.