February 7, 2024

Venting a Roof: A Guide For Roofers & Homeowners

Yes! You need holes in your roof. Why? Find out here.

Time to read:
5 Minutes
Written by
Jennifer Cote

Roof ventilation is critical to the health and long-term durability of a home and roof. It doesn't matter if you work on roofs in a hot and steamy climate or in the cooler north, proper roof ventilation is key.

In this blog, we're going back to the basics of roof ventilation. This will help you relearn the foundations of why it's important, and prepare yourself to educate homeowners about it.

We're covering:

  • Why you need to talk to homeowners about ventilation
  • The importance of ventilation
  • How soffits and vents work together

Educating Homeowners About Ventilation

When you're selling roofs or providing quotes, how you talk to homeowners can determine if you get the job.

Today's homeowners prefer DIY projects, want to understand processes, and are more engaged compared to homeowners 15 years ago. As a roofer, if you approach pitching as a chance to teach, you can build trust that goes beyond regular selling.

When explaining things like ventilation, try to answer the "Why" and "How" behind it.

Instead of simply adding vents onto a quote, speak to the homeowner. Explain it to them.

For example:

"Your roof only has one vent, which means that you could have a build up of humid air in your attic. This matters because X,Y, and Z. We're going to add X type of vent because X and Y, which will help."

Roofer installing roof vent

Some quick tips for educating homeowners:

  • Approach their curiosity with kindness
  • Use laymen terms and talk to them in ways they'll understand
  • Use drawings to help show how things work
  • Pause often to ask them if they have questions
  • Include everything you talk about in your proposal
  • Give them a way to contact you for any followup questions

The Importance of Proper Airflow & Roofing Ventilation

Roof vents aren't just an aesthetic part of a roof. There are a lot of benefits to ventilation.

During hot weather, the sun beats down on a roof, causing the air in the attic to become extremely hot. If the air has nowhere to go, it can cause issues like:

  • Mold growth in an attic, on walls, or in the home.
  • Uncomfortable temperatures eventually work their way into a home which make it hard for sleeping.
  • More money spent on AC or cooling.

You can think of roof ventilation as a type of natural air conditioner for your roof.

Poor ventilation is also bad for the roof. In cold weather, heated and trapped air from inside your home transfers to the roof, melting snow and creating a risk of ice dams. This clash of warm air with a cold roof also causes moisture buildup, potentially posing even more risk of mold growth and water damage.

Soffits and Vents: How They Work Together

By creating a steady flow of air, you can ensure that your roof stays cool year-round. But you don't just need roof vents on the roof. In order to achieve true air flow, you need a way for air to come in and flow up and out.

How Roofing Vents Work

A roof ventilation system requires vents for air intake and output.

Hot air rises. Roof vents work because it provides intake space for fresh, cool air to come in, then rise as it warms up, and leave through the exhausting vents. It creates an automatic circular motion that keeps air flowing through an attic.

Air movement in the attic regulates temperature, prevents moisture buildup (mold), and ensures proper distribution of heat and temperature. Hot and cold spots can impact the feel of the home.

Types of Roof Vents

You need both intake vents and exhaust vents for air flow. Here are some options for each.

Soffit vents

These vents are installed along the eaves or soffits of the roof, which are the underside of the roof overhang. They allow fresh air to enter the attic space from outside.

Soffit vents are usually designed as small perforated openings or grilles to blend with the architectural style of the building. They provide intake ventilation, bringing in cool, outside air to replace the hot air expelled through exhaust vents. Most residential homes have soffit vents.

soffit on a house under the eaves

Fascia Vents

The fascia board is the horizontal board located at the edge of the roof. These vents are installed along that edge.

These vents allow air to flow into the attic space from the exterior. They're less common than soffit vents but can be used in situations where soffit venting is not feasible.

Dormer vents

Dormers are structures projecting from a sloped roof, often with their own roof and window. These vents allow air to enter or exit the attic space within the dormer, helping to ventilate areas that may otherwise be poorly ventilated due to their design.

Box vent

A box vent is much like a dormer vent, but instead of being arched, they're shaped like a box. They can be made out of plastic or a type of metal. You see these on residential homes, mostly.

Ridge vents

Ridge vents are installed along the ridge line of the roof. The ridge is the peak where two slopes meet.

These vents run the entire length of the ridge and provide continuous exhaust ventilation. They're very much a passive vent, and don't need any type of motor or power to make them work.

A ridge vent with brown asphalt shingles installed

Most ridge vents are installed with a baffle. The baffle helps to increase air pressure, pulling up hot hair. Ridge vents without a baffle installed could have poor circulation, as well as excess debris or even animals making their way into an attic.

Ridge vents are designed to blend with the roofline, providing ventilation without looking like a vent. They're typically covered with asphalt shingles or other roofing materials to blend in with the roof.

Gable vents

Gables are the triangular portions of the outside of a house, created where a roof peak is. Gable vents sit in this triangle of space. These vents allow hot air to escape from the attic space and are often paired with soffit vents to create a natural convection airflow pattern.

Gable vents come in various shapes and sizes, including louvers or grilles.

Turbine vents

This type of vent is also known as a whirlybird. They are cylindrical vents with fins that spin as wind passes over them. This spinning motion creates a suction effect, drawing hot air out of the attic space and promoting ventilation.

turbine vent on a home with tile roof

Turbine vents are typically installed near the peak of the roof and require wind to operate effectively. They're not passive.

Today, solar powered vents are very popular because they don't require wind to make them turn, making them more efficient than turbine vents.

Off-ridge vents

Off-ridge vents are installed away from the ridge line of the roof, usually along the upper portion of the roof slope.

These vents provide additional exhaust ventilation and can be installed along with ridge vents or other types of exhaust vents to improve airflow throughout the attic space.

Powered attic vents

Attic fans are electric fans that are installed in the attic to provide ventilation. These fans remove hot air and moisture from the attic, improving ventilation and lowering the temperature inside.

Powered attic vents are often used in combination with intake vents, such as soffit vents, to create an effective ventilation system.

How Much Ventilation Each Roof Needs

Though the typical standard is the 1/150 rule, meaning that one square foot of free vent area is required for every 150 square feet of attic space, it's best to check with your local municipality for specific building codes.

A roof with the correct amount of vents will cycle air through 10-12 times per hour.

Roof Ventilation: A Key To a Healthy Roof

Outfitting a roof with proper roofing vents is an important piece of a roof repair. When done correctly, it can help to lower your cooling costs and extend the life of your roofing materials for years to come.

Brush up on other roofing terms, processes, and business tips, check out these resources:

EPDM roofing explained

5 key differences between residential and commercial roofing

Roof cement: The duct tape of roofing

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