What is Roof Ventilation?

In a vented attic, outdoor air enters through designed intake openings and exits through exhaust openings. Wind and temperature differences affect airflow. The amount and distribution of ventilation must suit the roof assembly and applicable code; ventilation does not guarantee that attic temperature and humidity always match outdoor conditions.

How does roof ventilation work?

Roof ventilation can help remove heat and moisture from a vented attic, but outdoor air is not always drier. Air sealing, insulation, bathroom and kitchen exhaust routing, and leak repairs also affect attic conditions and indoor comfort.

Benefits of Roof Ventilation

• Temperature Regulation: Roof ventilation helps regulate temperatures in the attic or roof space, preventing excessive heat buildup. This regulation contributes to a more comfortable living environment and extends the lifespan of roofing materials.
• Moisture Control: Adequate ventilation prevents moisture accumulation, reducing the risk of mold, mildew, and structural damage. Controlling humidity levels creates a healthier indoor environment.
• Extended Roof Lifespan: By minimizing temperature extremes and controlling moisture, roof ventilation helps extend the lifespan of roofing materials, preserving the integrity of shingles, sheathing, and other components.
• Energy Efficiency: Well-ventilated attics reduce heat buildup, easing the workload on cooling systems. This leads to lower energy consumption, contributing to improved energy efficiency and reduced utility bills.

There are two main types of roof ventilation:

• Exhaust vents: Let Stale Air OUT
• Intake vents: Bring Fresh Air IN
• Exhaust Vents: These vents are positioned near the roof’s peak or ridgeline and facilitate the exit of hot and moist air from the attic or roof space. Examples are continuous Ridge, Power, and box vents(turtle vents).
• Intake Vents: Placed near the lower part of the roof, usually at the eaves or soffits, intake vents allow fresh air to enter the attic. Soffit vents, intake air vents installed on the roof slope, continuous drip edge soffit vents (last 2 used for roofs with no soffits or space for soffit vents)

How do you choose a roof vent?

How much ventilation is needed

You may need multiple vents depending on your roof’s size, pitch, and shape

Type of Ventilation

Design intake and exhaust together for a vented attic. Soffit or other low intake vents and compatible high exhaust vents must provide the specified net free area and clear air paths. Select the exhaust system for the roof design; roof louvers are not universally obsolete.

Material Compatibility

Ensure that the chosen vent is compatible with the roofing materials used.

Ventilation Area

Calculate the required ventilation area based on guidelines or recommendations from building codes and standards. The right amount of ventilation is essential for maintaining a balanced airflow.

Important to know

Ventilated attics and rafter spaces

For a vented assembly, size net free ventilation and air clearances according to the applicable code and manufacturer’s instructions. The model-code baseline generally uses 1:150, with a 1:300 exception only when its conditions are met. A properly designed unvented assembly follows separate requirements. Confirm the currently adopted Georgia code and local requirements for the project.