How to Choose and Size a Gable Vent

A gable vent sits in the peak of the wall under the roof and adds character as much as airflow. Here is how to pick the right one.

Open or closed louver?

An open louver has actual slots for air movement and suits attics that need ventilation. A closed louver is purely decorative, with the look of louvers but no openings. Many homes use a closed louver for appearance and ventilate elsewhere. Check your attic ventilation needs with your builder.

Pick the shape

Spectis gable vents come in triangle, round, half-round, arch top, oval, octagon, diamond, rectangle, eyebrow and peak-top shapes. A triangle follows the roofline; a round or half-round works as a focal point.

Size it to the gable

Measure the width of the wall where the vent will sit and the pitch of the roof. A vent that is too small looks lost; as a rule of thumb it should read clearly from the street without crowding the eave or the rake trim. Triangle vents come as symmetrical units and as left or right versions made for sloped gables.

Material

Polyurethane will not rust, warp, split or fade the way aluminum, vinyl or wood can. Spectis vents are primed white and ready to paint to match your trim.

Installing

Attach with adhesive and corrosion-resistant fasteners, flash and caulk the perimeter, and paint all faces. Follow the installation guide on each product page.

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Oct 8th 2026 Spectis