Roof vents are a critical component of any roofing system. These vents ensure air can continually flow through the attic instead of getting trapped inside. When a roof is properly ventilated, the temperature inside the attic should always remain fairly close to the temperature outside. Without sufficient ventilation, the attic will remain hot and could develop moisture problems. This is especially the case in the summer months due to the heat the roof absorbs, greatly raising the temperature of the air in the attic. The heat then has the potential to cause serious damage.
How Ventilation Protects Against Damage
Roof ventilation plays slightly different roles during the summer and winter. In the summer, it ensures that the attic doesn’t get extremely hot and humid. High humidity in an attic is a major concern for several reasons. One is that it can lead to the underlying wooden parts of the roof system, including the deck and trusses or rafters, rotting, warping and cracking. Dry rot is an especially common problem that can cause severe damage to a roof. In the worst-case scenario, it can damage the underlying structure to the point that some or all of the roof has a risk of collapsing. The additional heat from a poorly ventilated roof also causes the shingles to deteriorate more quickly. That’s partly why you’ll typically have to replace your roof sooner if it doesn’t have adequate ventilation.
Another big concern, when an attic is constantly hot and humid, is that it can result in condensation forming on various surfaces. The moisture and heat then create the perfect conditions for mold growth, which can potentially spread throughout the attic, resulting in a major infestation. A mold infestation within an attic requires extensive and quite costly remediation. If mold is growing on any of the insulation, it will all have to be removed and replaced once the remediation is complete. Any other materials like wood will also need to be fully sanitized to ensure that the mold doesn’t return.
The main role ventilation serves in the winter is preventing ice dams from forming on the roof. Ice dams form as a result of the roof deck being hotter than the air outside. When it snows, the layer of snow sitting directly on the roof melts fairly quickly. The snowmelt flows along the roof and, eventually, refreezes near the eave, where the deck is much cooler. The ice then creates a dam that prevents the additional snowmelt from dripping off the roof into the gutter. That means you can end up with puddles of water on the roof. The water can then get underneath the shingles and leak into the attic. It can also soak into the wooden sheets on the roof deck and result in them rotting. When the layer of ice eventually starts sliding off the roof, it can damage the gutters as well.
Ice dams usually won’t form if the roof has adequate ventilation. Even though some of the heat from the house rises through the attic floor, the vents near the top of the roof allow all of this hot air to escape quickly. At the same time, cold air from outside continuously flows into the attic through some of the other vents. The attic stays fairly cool, and the roof deck typically never gets much warmer than the air outside. That means the snow on the roof never melts until the weather starts warming up and the sun shines on it. The snow also melts from top to bottom and flows straight off the roof instead of refreezing at the edges and creating an ice dam.
How Roof Ventilation Makes a Home More Energy Efficient
Whether or not your roof has sufficient ventilation also makes a major difference in how energy-efficient your home is during the summer months. Without enough vents in the roof, the temperature inside an attic during the afternoon and evening is commonly at least 30 degrees higher than the outside temperature. All of this hot air then results in parts of the house getting much hotter. That means your air conditioning has to run more and do more work, causing a fairly substantial increase in your electricity bills. This additional workload also typically shortens the lifespan of your AC system and can make it more prone to needing repairs.
Types of Roof Vents
Most roofs are passively ventilated, meaning that air naturally flows in and out of the attic. This happens as a result of hot air rising out through vents near the top of the roof. These vents are located either near the ridge or peak of the roof and/or near the top of each gable end. There are also additional vents that are usually located within some of the soffit panels underneath the roof eaves. As the warmer air escapes through the upper vents, it creates a pressure imbalance within the attic that causes air from outside to get drawn in through the lower vents. The result is that the air in the attic is constantly being exchanged with air from outside, and the indoor and outdoor temperatures remain about the same.
As long as the roof and all of the vents are designed and installed correctly, passive ventilation is usually sufficient. Nonetheless, various types of mechanical roof vents can be a huge help when you need additional ventilation. These vents use a fan that comes on occasionally to actively draw air out of the attic. The fan results in much more air flowing out of the attic, which causes more air to flow in from outside. One of the best options for mechanical ventilation is the solar-powered roof vent, which improves ventilation without adding to your electricity bill.
How to Know if Your Roof Has Sufficient Ventilation
One easy way to tell whether your roof has sufficient ventilation is to go up in your attic during the winter and see how hot it feels. If the attic floor is properly insulated and the roof has sufficient ventilation, the attic should feel fairly cold in the winter. Another way you can tell that your roof has inadequate ventilation is if there are frequently large icicles hanging off your gutters and eaves during the winter.
Icicles are a sure sign that there’s an ice dam on the roof preventing water from flowing into your gutters. Instead of flowing straight into the gutter and away from the house through the downspout, the water flows down over the ice dam before refreezing and forming icicles. All that said, the best way to know if your roof needs additional ventilation is to have it inspected by an experienced roofing company.
When you need any roofing service in Omaha or the surrounding areas in Central Nebraska or Western Iowa, you can count on the pros at Emerald Roofing. We’ve been in business since 2010 and have a team of expert roofers dedicated to the best roof repair and installation services. To schedule an inspection or a roof replacement consultation, contact us today.
