Attic Ventilation and Your Roof
We know it seems strange…you insulate your home to reduce temperature fluctuations and save on utility bills, but then you allow fresh air to flow through the attic no matter the time of year. However, that’s exactly how it works!!
Sealed attics trap excessive heat and moisture, which can lead to reduced shingle life. And the extra heat is not just a summer concern—come winter, hot attic air can melt snow on the roof during the day only to refreeze when temperatures drop overnight, creating ice dams that lead to interior leaking and roof damage. Ensuring your home has the proper attic ventilation, however, can save yourself the stress and hassle of an emergency roof repair.
Why Are Roof Vents Needed?
An attic needs ventilation to maintain the air conditioning of your home. In summer, your roof’s ventilation helps cool the roof and underlying water barrier materials, reducing the expansion of metal and slowing the aging of asphalt shingles. That’s not all though; roof vents are crucial in winter too. You can prevent an ice dam from forming in your rain gutters if you keep your roof cool so the snow won’t melt on top of your roof and then freeze again. Ice dams cause leaks and further damage. Even if you do not have leaks, additional weight can cause structural damage to your roof. The vents prevent this by circulating the coldest air from the eaves through the roof peak vent.
How Does Roof Ventilation Work?
An attic ventilation system provides continuous flow of air through your attic space, helping to remove overheated air and moisture from your attic and roof, and minimizing the effect of changing temperatures and moisture conditions inside and outside of your home.
There are several different types of vents that may be used to provide ventilation for the attic or roof area. Intake vents and exhaust vents are installed strategically at intervals in order to allow the air to move through the attic or roof area. In order to circulate attic air efficiently throughout the roofing system, several types of vents may be used at different locations.
Three different vent models can be combined to release all attic heat trapped in the attic:
- Ridge vents—openings that run the width of your roof along the ridge are often visible only to a trained eye. These are a popular means of ventilation, as they create no visible interruption to the roofline. This type of attic ventilation is installed by leaving a gap in the sheathing along the ridge and covering it with a perforated vent.
- Static vents generally protrude from rooflines thanks to special covers designed to keep all precipitation from entering the attic. They usually match the shingles in terms of shape and color so that the vents won’t look out of place. An example of a static vent type is a turbine vent, which uses wind energy to power the enclosed fan. A light breeze is enough to rotate the blades and pull heat from the attic. Regardless of the type of static vent you choose, it must be placed as close to the ridge as possible; homeowners concerned about curb appeal can place them only on the backside of the roof to minimize visibility from the street.
- Finally, unlike the rest of these models that utilize passive ventilation, powered exhaust vents feature an electric-or solar-powered fan to create an effect similar to that of a turbine. A powered exhaust vent turns on when the temperature in the attic reaches a pre-set limit and runs until the temperature falls. Although these powered vents do effectively draw heat out of a house, they will pull more cool air from leaks in the ceiling of the house (read: your home’s central air-conditioning system) than soffit vents due to the ease of installation. Considering that they require some electricity to run, the additional energy spent cooling the entire house by running an air conditioner may make this type of vent less desirable – especially if your attic is not well-insulated.
Spotting the Signs of Improper Ventilation
A poorly designed attic ventilation system can cause a wide range of problems. Some subtle and not-so-subtle things to watch out for:
- An unexplained uptick in your household heating and cooling bills, which can happen if your attic insulation gets wet and loses its effectiveness.
- More frequent HVAC repairs as heating and cooling equipment that’s under a heavier workload can become more prone to breakdowns or even premature failure.
- A noticeable buildup of ice along your roof edge during the winter months
- A wavy or rippled appearance to your home’s roofline and shingles that’s caused by warping of moisture-damaged decking underneath.
- Rust and corrosion on metal materials in the attic, such as nail heads, electrical boxes, light fixtures, and HVAC system components
- Dampness, water stains or frost on the attic side of your roof sheathing, or any evidence of deterioration and decay of the roof’s structural supports.
- An increase in discomforting allergy symptoms or respiratory illnesses among your family members, which may be related to the spread of fungi spores through your indoor air supply from mold growth in your attic.
When checking your roof or attic for these signs, keep safety in mind. Rather than climbing up on your roof, walk around the outside of your home and look up using binoculars from the ground. If you head up to the attic, make sure the space is well-lit, that you have a sturdy walking path, and are wearing appropriate protective gear.
What to Do About a Poorly Ventilated Attic
A certified roofing contractor can assess whether your attic has adequate ventilation – the code typically requires one square foot of ventilation if you detect or are concerned about any of the above warning signs. ft. of net free-vent area (NFVA) per 300 sq. ft. of space in an unfinished attic space. Depending on the situation, they can advise you on what options are available to improve ventilation and ensure it’s effective.
If your roof is getting close to the end of its lifespan, or the decking or other components are damaged or deteriorated, repairs or a replacement may be recommended.If you suspect you have may have a ventilation issue with your attic, be sure to contact us today for your FREE inspection.