Will drilling holes below and above a skylight really provide airflow?

Drilling holes below and above an obstruction such as a skylight will provide airflow. See below for more details.

The tip to drill 6 one-inch holes below and above a skylight will provide some airflow. The amount of airflow will depend on the wind speed and the types of intake and exhaust vents being used. Assuming an externally baffled ridge vent and a continuous-style intake vent (The Edge Vent, or Vented Drip Edge, or Continuous Soffit Vents), the following dynamics would occur: The rafter bay below the skylight (obstruction) will be under high static pressure because its only openings are the intake vents low on the roof. The rafter bay above the skylight (obstruction) will be at a low static pressure because the ridge vent is pulling air from the cavity. By opening up the obstructed bays to the bays beside, the lower bay under high static pressure will have the two bays beside at lower static pressure; therefore the air will move from the obstructed bay to the clear bays. The top bay will have a lower static pressure than the bays beside and will thus suck in air from the bays beside. It is important that the holes be open to the airspace in the rafter bays. For example, be sure that the holes are above the insulation. If they are not above the insulation, insulation baffles will need to be used and possibly altered to ensure that the air spaces are open to the hole in the rafter. If the holes are covered or are not cut, the bays that the skylight cuts across will not be vented and could experience condensation issues. The basic result is an un-vented cavity.