A Guide to Roof Ventilation Basics

A Guide to Roof Ventilation Basics

Learn more about roof ventilation and different types of roof venting systems.

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Understanding the Importance of Roof Ventilation

Your roof ventilation system is extremely important for energy efficiency, airflow, and temperature regulation in your home. The primary purpose of roof ventilation is to keep the air space above the roof insulation as close as possible to the same temperature as the outside air. Your New Jersey roofers, Allied Roofing Solutions, are experts in establishing the best roof ventilation system for your house. In this guide, we cover the basics of roof ventilation including the purpose of roof ventilation and the most common types of ventilation systems.

Purpose of Roof Ventilation

Roof venting allows air to be removed from the attic in order to maintain temperature and humidity close to matching the air outside. This may be not easy to achieve perfectly. However, you are really trying to avoid extreme fluctuations in the temperature from season to season.

Because hot air rises, in the summer the air in your attic is hot and in the winter the heat from your home warms the attic air. Good venting ensures that cool air can enter the attic near the eaves and exit near the peak.

When you have improper ventilation, you can experience these problems:

  • Extra moisture in the attic space
  • Ice dams in the winter months
  • Less than optimum air quality due to poor airflow in the attic space during the summer
  • Overworked HVAC systems that are being worked too hard in order to cool the second and third floors of your home
  • Roof sheathing dry rot

Not only does venting keep your home comfortable, it also reduces condensation that can damage the roof structure and cause mold to form in the attic and throughout the house. If your home’s attic gets very hot in the summer or if you have a musty, moldy smell, you need a ridge vent. But, the cold months can also show symptoms of a poor roofing system by forming ice dams. 

When you are replacing a roof, you will need to look at the ventilation system to use. Allied Roofing Solutions can help you with choosing the best venting system.

Roof Venting Systems

The best roof venting system is a combination of soffit vents and ridge venting. Soffit vents are for intake air while ridge vents, turbine vents, and hood vents allow air to leave passively the attic. Gable vents allow air to flow in or out but aren’t the best at helping the air flow evenly in the attic. When choosing the best system for your house, it’s best to consult with an experienced roofing specialist before making a final decision. 

Exhaust Vents

Ridge Vents

Ridge vents are the most commonly installed exhaust vents. These are at the peak of your roof and go across the entire roof line. They let the hottest air escape the attic since they are located at the roof’s highest point. Additionally, because they span the entire roof line, they have the surface area that is required in order to expel the largest amounts of hot air. When ridge vents are used in combination with intake vents at the bottom of the roof (soffit vents), you have the best chance for vertical ventilation.

Off-Ridge Vents

An off-ridge vent is installed close to the crest of your roof and is similar to a box vent. The most popular off-ridge vents are 4 feet long and usually made of galvanized steel. Off-ridge vents are useful when the ridge line of the roof is small. If the roof of your house is complex with many pitches, peaks, valleys, and dormers, and without a continuous ridge line, you may need to install off-ridge vents to achieve the proper ventilation.

Box Vents

Box vents, also called “louver vents,” are more popular than off-ridge vents. A box vent is square and is installed in a similar fashion as off-ridge vents. Box vents are placed strategically in smaller areas that need air vented where a ridge vent may be impractical. Like off-ridge vents, box vents are useful on a roof that is more complex such as a hipped roof.

Attic Vents

Attic vents come in both hard-wired and solar-powered versions. A powered attic vent pulls stale air from the attic. The concept is similar to putting a box fan in a window to pull the hot air out. There are some disadvantages of using powered attic vents. A powered vent can pull cooler air through the floors of the home and out of the attic during the summer, resulting in increased energy costs and making the air conditioning system work hard than it should. A weaker powered vent can simply circulate the air rather than expel it. Consistent airflow can avoid mildew but it may not be getting the hot air out of the attic. 

Roof Turbines

Roof turbines, also called “whirlybird vents,” use the wind to rotate the blades. The blade rotation causes the air in the attic to be pulled up and out of the house. A roof turbine needs wind of at least 5 to 6 miles per hour to activate and spin the interior blades, so when there is only a slight breeze or no breeze these turbines aren’t effective at all. 

Intake Vents

Intake vents bring fresh air into the attic. Together with exhaust ventilation creates a vertical ventilation system. There are only a few options for intake vents.

Soffit Vents

Soffit vents are the most popular intake vents and are the base of any good vertical ventilation system. Soffit vents are installed directly on your eaves and are located underneath the roof line. Depending on the style of your roof, you may need continuous soffit vents or individual soffit vents. 

Continuous soffit vents are long and wrap around all of the eaves of a house. These provide a lot of surface area for the air to pass through. Individual soffit vents are smaller, typically rectangular in shape, and placed 5 to 6 feet apart along the eaves. Individual soffit vents are not as effective as continuous vents because they provide less surface area for air intake.

Gable Vents

Gable vents are usually found in older homes. These are triangular vents that are placed in a gable. A gable vent provides horizontal or cross-ventilation to keep air moving through the attic. Typically, there would be gable vents on two sides of the house so air would flow in one side and out the other side. 

Over-Fascia Vents

Over-fascia vents are a newer type of roofing intake that work when a roof doesn’t have sufficiently sized eaves to fit soffit vents. A fascia vent is installed at the top of the fascia board and gutter and directly underneath the starter row of shingles. These vents are beneficial for homes where soffit vents cannot be used, especially for complex roofs where the use of soffit vents would not be adequate.

Contact Us for Roof Replacment and Ventilation Needs

If you are considering replacing your roof, contact our experienced and professional team at Allied Roofing Solutions. We can offer you advice on the type of roofing appropriate for your house, including roof ventilation systems that will do the best job. Our roofers are licensed and can replace your roof or repair your roof with top-quality service and skill. We serve New Jersey residents in Bergen County, Essex County, Hudson County, Middlesex County, Morris County, Passaic County, and Somerset County. Call us at  (201) 773-0633 or complete the free estimate form to schedule an appointment.