Gable Vent — Attic Airflow, Leaks, and Replacement

A gable vent is a louvered attic vent installed in the gable end wall to let outside air move through the attic and reduce heat and moisture buildup.

What It Is

A gable vent sits high on the triangular end wall beneath the roof peak. Its louvers keep out most rain while allowing attic air to move in or out as wind and temperature differences change.

Gable vents are one part of an attic ventilation strategy, not a cure-all. They work best when the attic also has balanced intake and exhaust paths and when insulation does not block airflow at the eaves.

Types

Common types include wood, vinyl, aluminum, and composite gable vents. Some are purely passive, while others hold an attic fan or include insect screening behind the louvers.

Where It Is Used

Gable vents are used on houses with gable roofs, detached garages, sheds, and older homes where ridge-and-soffit vent systems were never added. They are especially common on traditional framed attics with open air space above the ceiling insulation.

How to Identify One

Look at the exterior gable end wall near the roof peak for a rectangular, triangular, or half-round louvered opening. From inside the attic, you can usually see daylight through the vent and a screen or framing box around it.

Staining, cracked louvers, torn screens, and signs of birds or wasps are common clues that the vent needs attention.

Replacement

Replace a gable vent when the frame is rotted, the louvers are broken, the screen is damaged, or water is getting into the wall or attic. A new vent should match the rough opening size, material exposure, and the home's overall attic ventilation plan.