Roof ventilation

The roof of your home covers the attic space, which is an area we like to think of as the lungs of your house. Your attic is constantly “breathing” in and out as fresh air enters, circulates, and exits to maintain a proper balance of temperature and humidity. This airflow is critical to the health of your home and the lifespan of your roof so proper roof ventilation is key.

Ensure Good Airflow

A properly vented roof will serve to regulate and maintain optimum air temperatures and humidity levels in your attic. Without proper ventilation, stagnant attics become ideal spaces for moisture to collect and mold to form, both of which are unhealthy conditions for your roof, your home, and you! An attic with sufficient ventilation will have equal levels of incoming and outgoing air, or air movement, and will be able to maintain ideal temperature and humidity levels year-round.

In the winter, a properly vented roof allows outside cold air to enter and replace warmer air, which rises with convection. This serves to keep your attic cold, and a cold attic is exactly what you want, especially in the event of an ice or snowstorm. When snow and ice melt too quickly, ice dams can form and cause damage to your roof and gutters. A slower melt-off helps prevent this from happening. A warm attic in winter is also more likely to become too humid and is at risk for moisture buildup and mold. Keeping air on the move prevents condensation on the cold plywood roof deck, which can lead to mold growth. 

During summer a well-vented roof helps regulate temperature by allowing hot air to flow out of the attic. As hot air rises, it escapes through the upper vents at the top. This continual flow of air is critical to preventing moisture build-up and condensation within your attic. Moisture in your attic will lead to other problems like mold and can shorten the lifespan of your roof, as well as damage your home’s main structure. 

Saves Energy and Money

Proper roof ventilation will also help you save energy and money. Improperly vented attics will result in excessive heat build-up during the hotter summer months, causing your air conditioner to work harder to keep your home cool. Excessive attic heat can also cause roof shingles to age at a faster rate. It can also cause the plywood decking of your roof to delaminate because the glue can’t keep up with the expansion 

Wasted energy, condensation, mold, ice dams, rotting roof decks, aging shingles, and a shortened roof-life all add up to expensive problems that proper roof and attic ventilation can help prevent.

types of ventsTypes of Vents and Their Purpose

Both upper roof vents and lower vents along the soffits are necessary to create the right balance and exchange of incoming and outgoing airflow. 

Roof vents allow rising hot air and moisture to escape from the attic, preventing heat build-up and condensation, 

roof vents

depending on the season. There are two types of roof vents: ridge vents and box vents. A ridge vent is an air exhaust vent installed on the peak of a roof. A box vent is a hole cut into the roof with a box cover, and while positioned high on the roof, box vents are typically placed near the ridge or peak.

Soffit venting allows cooler, fresh air, to flow into the attic at the lowest points. The soffit is the part of your roof overhang that meets your siding. Together with roof vents, soffit vents 

soffit venting

create a passive system that effectively enables air to flow into, up, and out of the attic.

There are two types of soffit vents: rectangular and continuous. Rectangular vents are cut into the blocking between the rafters of your home. With continuous venting, the soffit is vented all the way around the attic area. This type of venting is for closed soffits where the rafters are not visible. 

Pro tip: Always keep all of your roof and attic vents open and un-impeded by debris to maintain proper airflow. 

How do I know if my roof is properly vented?

Every roof needs both roof and soffit vents. Simply walking around your house and looking at your roof and eaves will tell you if you have vents, but this alone does not mean you have sufficient ventilation. Inspecting your attic for signs of moisture is a more reliable way to determine if you have adequate venting. Any moisture on the tips of nails is the first sign. You can also touch your ceiling just below your attic on a warm sunny day. If it feels hot, your attic may be overheating. If it is winter, you might grab a flashlight and inspect your attic for condensation. Excessive heat and moisture are signs your roof and attic are not properly vented.

Of course, the best way to tell if your roof’s ventilation system is adequate is to have a professional inspection. This is a service we offer at Pacific West Roofing. Our experienced inspectors will give you an honest assessment of your roof, attic, and vents, so you can have peace of mind knowing your roof is in good shape and sufficiently ventilated, or be alerted to any problems that should be addressed before they become costly repairs. Contact us today to schedule an inspection.


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