Closeup of a roof vent on a house.

As a responsible homeowner, you know the importance of keeping your roof and attic well-insulated. Insulation is, after all, your primary line of defense against thermal transfer from the outside, preventing heat loss in the winter and heat gain in the summer, right? This is true to some extent, but even the best insulation won’t work as effectively as it should without proper roof venting.

While most homeowners know about the benefits of good insulation, the role that roof venting plays in keeping your roofing system in optimal condition is less understood. This means DIYers often make the mistake of covering over the vents under the eaves when they’re installing insulation.

roof ventilation
Roof vent

The main purpose of roof ventilation

It might seem logical that if you’re going to spend time and expense to keep heat in, you don’t want cold air blowing into your attic through these vents, but believe me when I say that this is a mistake. Actually you want cold air blowing in the attic. When it is cold outside, the primary purpose of ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow and to vent any moisture that moves from the conditioned living space to the attic. In a warm season, the purpose of venting is to expel hot air from the roof and attic and to reduce the temperature in the building. 

Proper roof venting helps protect your roof and home in two key ways;

roof ventilation diagram
  • It brings fresh, cool air into the attic through the intake vents located under the eaves
  • It releases hot, moisture-filled air from the exhaust vents at the ridge of the roof.

This keeps the attic air circulating and prevents the build-up of too much heat, even in summer, benefitting you in many ways.

Keep Your Utility Bills Down.

In the summer, if there’s no air circulation, hot, stagnant air will build up under the roof, heating your ceilings and seeping into your living space, making the air-conditioning work harder and consume more energy.

Increase Your Roof’s Lifespan.

If your attic gets overheated, your roof will be heated on its interior surface, in addition to the exterior one. This will cause the underlayment and then the shingles of your roof to dry out and crack much quicker than you’d expect, leading to expensive repair work.

Roof without ventilation
Roof without ventilation

Prevent Mold and Moisture Damage.

In the winter especially, condensation can be a problem when warm air rises from the interior of your home and hits cold surfaces. If your attic isn’t properly ventilated this moisture will build-up, leading to mold, moisture stained ceilings, and even structural damage to the rafters, and trusses of the roof itself. If this problem isn’t spotted in time, it could necessitate a complete roof replacement.

Prevent Ice Dams.

While they might look very picturesque, icicles hanging along the edges of the roof are not something a homeowner wants to see. They are a sign of Ice Damming, a problem commonly associated with a badly-ventilated attic. If your attic retains hot air rising from below and becomes too warm during winter, your roof will heat up. This will cause the snow on it to melt. The resulting water will flow down to the edge of the roof and gutter, where it’s considerably cooler, and refreeze, building up as the cycle is repeated with each new snowfall. In the end, water will back-up under the eaves and even into the attic.

ice dams

As you can see, proper ventilation in your attic plays a vital role in preserving the integrity of your roof and protecting your home.

How to know if the roof has proper ventilation?

Here are some steps you can make and inspect your roof ventilation:

  1. First, take a Look at your eaves and roof. If there are no attic vents on the roof or in the eaves, you should add some.
  2. Touch your ceiling on a warm, sunny day. If your ceiling is hot, that tells you that the attic is acting like a solar oven. It is raising your cooling bills and should improve the ventilation of the roof.
  3. Thick ridges of ice on your eaves or ice damming in winter are a sign of poor attic ventilation. The warm air that escapes the rooms below gets trapped in the attic. Snow melts and the water refreezes on the cold eaves, creating ice dams.
  4. The warm air that escapes living space also carries moisture that will condense on rafters or roof sheathing. During the winter inspect your attic and look for dampness or frost. If you find any of those, it a clear signal that your roof needs better ventilation and some attic vents.
attic insulation and ventilation

And remember, if you do have any attic ventilation or other roofing-related problems, contact us here at Ridgecon Roofing Contractors for a free quote on repairs.