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How often do you think about your roof’s ventilation? If you’re like most people, probably not very often. But did you know that good ventilation can extend the life of your roof, reduce your energy bills, and protect your attic/crawl space from condensation and water damage? If you are thinking about a new roof, now is the time to be talking about ventilation with a roofing professional.

What does ventilation do?

Ventilation allows for a continuous flow of air in your roofing system—which helps ensure that the temperature of the area directly underneath the roof closely matches the outside temperature. It allows warm air to escape, and be replaced with cooler air from the outside. Typically, homes have passive ventilation systems.

Poor or no ventilation can result in:

  • Moisture or condensation build up on your roof deck, and even inside the house.  This can result in rot, mold, fungus, water damage, or damaged insulation.
  • Extreme differences in temperature between the outside, and attic area of your home. Without proper ventilation, there can be over a 40-degree difference between the warmth of the house and the surface of the roof.  In the winter, this can result in ice damming.  In the summer, this can result in broken or damaged shingles.
  • High cooling bills in the summer.  With no place to go, hot air becomes trapped in the house.
  • Your roof’s life reduced by up to half.

What are the options for intake vents?

Most often, homes will have either soffit vents, or edge vents.

A soffit is the underside of your roof’s under hang. Soffit vents are simply vents in the soffit that allow for cooler air to enter the ventilation system.

Some homes have little or no overhang, and so a soffit vent is not feasible. In this case, edge vents are a great choice. A channel is cut into your roof deck about a half foot away from the edge. An edge vent is attached, and then covered in shingles. This allows air to enter under the shingles, and into the channel and ventilation system.

What are options for discharge vents?

These are typically either box vents or ridge vents.

Box vents are installed over holes cut into the roof. They use winds and convection to allow the warm air and moisture to escape from the attic space. The number of box vents used is dependent on the square footage of the roof—there are typically more than one.

Since box vents are not continuous, there are spaces between the rafters where air can be “stored” and can’t be forced out. Box vents are also more prone to leak and to allow small animals to enter your home than the alternatives.

Box vents are most often used in homes with flat roofs, roofs with very small ridges, and uniquely designed/shaped roofs.

A ridge vent is installed all along the peak of your roof. It allows for continuous and uniform air flow.

Ridge vents have a seamless look, and blend in with the roof. Ridge vents are best for roofs with an appropriate peak (most roofs!).

Some older homes may be currently equipped with gable vents. Gable vents are highly decorative, but do not allow for appropriate ventilation for a host of reasons. When installing new vents, gable vents can simply be covered from the inside—leaving its decorative appeal while adding appropriate ventilation to your home.

When you meet with your roofing professional about your roof be sure to take the time to discuss ventilation. And if you are looking for a free residential roof and ventilation estimate or evaluation, contact us anytime at 585-400-7663 or office@400roof.com.