Every residential and commercial roof must have proper roof vents installed to create sufficient intake and outflow of air in the attic. Without appropriate ventilation, a number of potential problems could crop up, such as ice dams, mold buildup or wood rot. This will then increase the lifespan of the roof. In addition, good ventilation can reduce energy costs by decreasing an excessive buildup of heat in the attic and improving indoor temperatures.
There are two important types of roof vents. Exhaust vents get rid of the stale air in an attic space while intake vents let in fresh air. However, in some cases, certain roofs may not be able to have intake vents installed, in which case an exhaust vent must still be in place.
Roof Exhaust Vents
The type of exhaust vent that is best for a home or business will depend on the style of roof and on climate and budget concerns. However, as with intake vents, it is best to have exhaust vents installed during initial roof installation to avoid extra costs later. Exhaust vents are usually placed as high as possible on a roof while intake vents are installed lower.
The most commonly used roof exhaust vent is the ridge vent. This vent is placed on the highest part of the roof where wind is most likely to blow over it, helping to remove stale air as well as excessive moisture. After this vent is installed, special ridge cap shingles are placed over the vent for extra protection.
While ridge vents are quite popular across the country, some roofers recommend different types of exhaust vents depending on the roof style. For example, an off-ridge vent is placed close to the ridge of a roof but is more useful than a traditional ridge vent when roof peaks are particularly short or complicated. Box vents work similarly to off-ridge vents but are actually more prevalent because they vent well despite their small size. Wind turbines can be a good solution in breezy areas, but they require wind speeds of at least five miles per hour.
There are a couple types of powered exhaust vents as well. The first option is the hard-wired power attic vent. This vent runs on the home or business’s electricity and blows hot air out of the attic space. While these vents are not as cost-effective as non-powered vents are, they can significantly cool attic spaces in very warm climates. Solar-powered attic vents remove stale air from attics in much the same way but do not come with any additional electrical costs. However, with any powered exhaust vent, one must take care not to choose too powerful of a model in order to prevent the building’s already warmed or cooled air from escaping.
Roof Intake Vents
Although intake vents may be impossible to place on every type of commercial or residential roof, they improve energy costs by working alongside the exhaust vents to more efficiently replace stale air. The type of intake vent seen most frequently on residential roofs and some commercial buildings are soffits. These vents are quite effective at letting in fresh air through tiny holes found on the the underside of the overhang. Most newer homes feature continuous soffit vents that extend along the entire roofline. However, older buildings may only have individual soffit vents, which look much like the cold air return vents inside a home.
Another type of roof vent that more frequently appears on older homes is the gable vent. These vents are located on the sides of a home or business to allow for cross-ventilation. They work best with simple roof styles rather than on complex roofs with multiple ridges and peaks.
Drip edge vents and over-fascia vents work similarly and are usually equally effective. However, they can be more difficult and expensive to install despite being excellent solutions for roofs that cannot support soffit vents. Both make use of horizontal air flow coming directly at the roof where it can flow into the attic space and out through an exhaust vent placed near the peak of the roof.
A roofing contractor will ensure that a building has the correct number of exhaust and intake vents to prevent the loss of air from living or working spaces to the outdoors. This balance will ensure proper air pressure and will save on energy costs throughout the year. In addition, regular maintenance of all roof vents is important to ensure that there are no airflow obstructions.