Are roof vents required?

You’ve probably seen roof vents on your own roof and other roofs and may have even wondered if they are really necessary. The short answer is yes they are!

Let’s look at the reasons why they’re required.

Manufacturer’s warranty

Did you know that if you have a manufacturing defect in your shingles, it’s usually covered for 30, 40, or even up to 50 years?

However, the manufacturer requires that their shingles be installed the way they are designed to be used for that warranty to be honored. If you don’t have proper ventilation, your attic can heat up far more than your shingles are designed to withstand. That means they’re essentially sitting on top of an oven.

That excess heat bakes your shingles and shortens their life, which is why the manufacturer requires proper ventilation.

We had a customer once whose second-story attic was not ventilated at all. His attic temperature was approximately 145 degrees Fahrenheit! We put ridge vents on when we replaced his roof, and the temperature in the attic dropped to 120 degrees.

Building codes

Building codes also require that roofs have proper ventilation. So when you get a new house, theoretically it should have proper ventilation.

In practice, the actual enforcement of the code varies greatly. In general, home builders are using subcontractors, and they assume their roofing subcontractor knows what they’re doing. However, in our experience, around 75% of roofers don’t realize how proper ventilation actually works.

Issues caused by lack of ventilation

If you don’t have proper roof ventilation, it can cause structural damage, high heating and cooling bills, and even mold in your attic and in the walls. Insufficient ventilation results in higher temperatures, increased condensation, and more.

You have to have the right number of vents, which varies based on the type of vent you choose. They also have to be properly placed, and you have to have proper intake down where the roof meets the house in order to avoid all of these problems from inadequate ventilation.

Determine the right ventilation

We use a roof vent calculator to ensure proper ventilation for every home. When I’m going to meet with a homeowner, I go to the county website and look at the layout and square footage of the house.

Let’s say the house is 1,800 square feet. I have to calculate based on the attic’s square footage, which includes the garage, covered patio, and porch. So that house would be around 2,500 square feet of attic space.

I punch that number into our roof calculator, then I select the vent type. Of course, the number and placement of vents will vary based on the type, so that information is necessary. The calculator tells me how many I need to install, but I still have to make sure they’re placed properly and that the intake is sufficient as well.

You may have seen a house where they have a ridge vent on every peak of the house. That’s actually not properly vented! In fact, because of how physics work, it’s probably causing issues that wouldn’t be there with less ventilation.

So are roof vents required? Yes, they are, and for good reason. We recommend having a professional come out and check to see if your roof is properly ventilated before it starts causing bigger problems.

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