How Do I Know if I Need Cornice Vents in My House Attic?

Regardless of season, cornice vents provide your attic ventilation.

In fact, cornice vents help you in two ways:

1| Eliminate condensation in the attic. This condensation is due to the heat loss from your home.
2| Let the hot air to get out, during the hot season. This will reduce your house-cooling bill.

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Roof and Attic Protection

Therefore, it is a good idea to install cornice vents. They have a critical role in the air circulation.

Cornice vents allow the outside air to get inside the attic and the inside air to get outside.

Winter Months: Airflow is extremely important in the cold season. The temperature from inside will be correlated with outside temperature, preventing ice dam formation.

It is well known that ice dams can damage your roof, which will lead to water leaks and of course, damages to your home.

Therefore, if you live in areas with low winter temperatures, it is a smart idea to install cornice vents.

Summer Months: Airflow is vital in the summer months too. Cornice vents allow the hot air to get out. A hot attic will make your roof shingles to curl, which will affect its integrity.

Roof/Ridge Vents

Cornice vents are not required, if your attic has a ridge vent or roof vents.

In addition, you can remove your cornice vents if you intend to install a ridge vent or roof vents.

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How to Properly Size Cornice Vents

You can have condensation or shingle curling problems, even if you have installed cornice vents. This is mainly due, to an improper sizing of cornice vents.

Cornice vents sizing depends on two factors:

1| The roof slope
2| The attic area

How to calculate the right size:

– Measure the distance between the attic floor and peak of the ceiling
– Divide by the house width
– Place the result in front of figure 12 (Example – 6:12);

The slope of the roof = for every 12-inches horizontal you have 6-inches vertical.

– Attic Area = Width x Length.