RoofViews

Residential Roofing

5 Common Installation Mistakes When Venting Attics

By Wendy Helfenbaum

October 21, 2021

Roof intake vent

Roof vents form the base of a home's attic ventilation system, helping it breathe while preventing roof system damage year-round. That's why it's important to understand how the various components work together to create a balanced, effective attic ventilation system.

Here are five of the most common ventilation installation mistakes—as well as how to avoid them.

1. Placing Intake Vents Too High or Exhaust Vents Too Low

A balanced attic ventilation system draws in fresh, cool air at the lowest part of the attic space and exhausts warm, moist air at the highest point. If either of these vents are placed incorrectly, they reduce the entire attic space's exposure to continuous air flow, reducing the overall system's effectiveness.

If an exhaust vent is placed too low on the roof, or if two exhaust vents are stacked, one of the vents might then act as intake and disrupt—or short-circuit—the airflow through the entire attic space, reducing how effective it can be.

Make sure that the intake vent is placed at the lowest possible point of the roof (usually at or near the soffits) so that it lines up with the lowest part of the attic space. Exhaust vents should always be placed at the highest possible point on the roof (at or near the ridge) which typically aligns with the highest part of the attic space.

2. Mixing Exhaust Products within the Same Attic Space

Installing two or more different types of exhaust vents within the same attic space can also short-circuit proper airflow. When this happens, some of the exhaust vents may act as intake vents, restricting airflow to only the part of the attic space underneath those exhaust vents. Mixing exhaust products could also allow weather or debris to infiltrate the home.

Mixing Exhaust Products

If the wrong type of vent for a specific roof design is installed, that can lead to mixing products. When a ridge vent is installed on a hip roof with very little ridge line, for example, it may not provide enough exhaust for the attic space. When this happens, another exhaust fan such as a roof louver or a power vent will be added to boost the ridge vent. However, doing this can lead to problems.

A best practice is to install one type of exhaust vent on the attic space that is able to meet the exhaust NFVA (net free ventilating area) requirements, allowing the air to flow continuously throughout that attic space.

3. Cutting the Ridge Vent Opening Too Long

Sometimes, a ridge vent might be installed across the entire ridge because it looks good, but there's no need to cut open the entire ridge air slot below the vent. Cutting an opening that's too long could lead to too much exhaust, disrupting the balance of the entire ventilation system.

Check that the opening of the ridge air slot matches the amount of exhaust NFVA required for a specific attic space. For example, if an attic space requires 288 square inches of exhaust and you're using a 4-foot plastic ridge vent with 18 sq. in. per lineal foot of NFVA, then only 16 ft. of the 40-ft. ridge should be cut open.

Always open the ridge air slot according to the required exhaust NFVA for the attic space, and then balance that with the same amount of intake NFVA.

4. Clogged or Blocked Intake Vents

Even when intake vents were correctly installed, they may become ineffective over time if the outside portion becomes clogged with paint, dirt, dust, or even spiderwebs. Vents may also get blocked from the inside if the attic insulation is installed over the vents.

Clogged or Blocked Intake Vents

Keep the intake vents clean by removing any debris that may have accumulated over time. If necessary, use attic baffles to keep insulation away from the intake vents. Don't forget to check that a hole has been properly cut in the soffits to allow air to enter the intake vents.

5. Having Missing or Inadequate Intake

Intake is arguably the most important part of an attic ventilation system. When there is inadequate intake—or none at all—an exhaust vent may not function properly.

Static exhaust vents like ridge vents or roof louvers hinge on adequate intake, but the same also goes for powered exhaust vents, which will have to work too hard to pull air through the attic space, resulting in the premature failure of the power vent's motor.

Always check that you have a balanced attic ventilation system with the proper amount of intake and exhaust ventilation for the attic space being ventilated.

For more information and tools to calculate the amount of ventilation products needed for your attic roof vents, visit gaf.com/ventcalculator.

About the Author

Wendy Helfenbaum is a Montreal-based journalist, content marketing writer and TV producer who covers design, architecture, real estate, gardening and travel for many publications and brands, including Country Gardens, Metropolis Magazine, Realtor.com, Marriott Traveler, Costco Connection, Toll Brothers, PBS NextAvenue.org and many more. Wendy loves keeping up with current design trends and is addicted to home improvement DIY reality shows. Follow her @WendyHelfenbaum.

Related Articles

GAF Roofing Academy Graduate holds up his certificate of achievement.
In Your Community

How Attending the GAF Roofing Academy Changed One Graduate's Life

Meet Austin Teague, recent GAF Roofing Academy graduate who shares his transformational journey from ball field to the roof. Prior to the GAF Roofing Academy, he was involved in sports, worked in customer service, but lacked the experience needed to break into the roofing industry. Once he graduated from the GAF Roofing Academy, doors were then opened for him, leading to well-paying jobs as an installer and later as a salesperson, where he is currently on track to meet his financial goals.Attending the two-week program proved to be a life-changing decision for Austin, providing him with the tools and confidence needed to succeed. The course not only equipped him with technical expertise, but also instilled in him the ability to educate customers effectively. Take a listen as Austin shares his story of how he found clarity and direction in his professional life, enabling him to thrive in the industry and build a successful future for himself and his family.Are you interested in a career in the roofing industry? Look for a Roofing Academy course in your area. Video TranscriptMy name is Austin Teague. I'm originally born in Tyler, Texas. Moved to Washington when I was a kid at ten. Well, prior to joining the Roofing Academy and, you know, taking my skills to that test, I was sports, strictly sports. Everything in my life I would, you know, I'd work a customer service job. I was in the, you know, the retail industry. I worked at Walgreens, but my personal life was hectic. It was football practice, baseball practice. It was always something going on.There was always something to do. Everything when it comes to roofing, for me, started after the Roofing Academy. When I tried to get into the roofing industry before going to the Academy, nobody wanted me because I had no experience. They're going to have to train everybody on the job. But because of the roofing academy, because I knew what I was going to do day one, I knew what my job was. I couldn't run into any hiccups because I knew what showing up day one was going to look like.[00:00:56.770]So they gave me a GAF certificate with my name, the location I trained out of, and then when I graduated. And what I did with that is I took it to every single applicant or job interview I had because I wanted them to know that I have this certificate. Not saying I have it, but also bring it, so they can see it.After the academy, I landed a job at 28 an hour as an installer, which is substantial in this living, making life, making payments. And then after that, I got bumped up to 32 an hour when I was working in New Mexico. And now that I'm sales, I'm straight commission. But in this month, I'm on pace to hit 20,000. Our goal at Tristate is to educate the customers firsthand. So being at the Roofing Academy allowed me to know roofing like the back of my hand. As an installer, as a sales, as an owner, you got to see the value in the systems. And it allowed me in my head to build those value, actually explain it to the customers. Where is this number coming from? Well, it's coming from this material because this material is going to cost more, of course, but it's obviously better.[00:01:58.920]I think someone coming to the Roofing Academy right away, no experience, is going to set you up for success. That's what you want. You want to be set up for success. You want to be as many tools as you can in your tool belt to get you to that point you want to be in life. And showing up to the Roofing Academy, it changed my life drastically. I didn't know what I was going to do. I literally didn't know, if roofing wasn't the pathway for me- what was the next plan?I was just grateful. I mean, I was one day on indeed looking for jobs and I saw the Roofing Academy post on indeed looking for academy students, and I thought, why not? What's two weeks out of my life that I get to change it? If I get an opportunity to change it and that two weeks changed my life. There's no time wasted. You're here from nine to three or nine to four at the latest for your classes.You're with guys that you actually enjoy being around. The guys in my class or in the class today, they're fun guys. They all get to make mistakes and learn from each other. And it just makes me grateful that I got that opportunity to make something of myself. I'm not just another guy on the street.[00:03:00.340]I don't know what my life's going to look like in the next six months, but I guarantee it's not going to slow down. I'm going to work harder than ever. I know I got two kids at home. I have something to push me. I would say that all the success started with the Roofing Academy because my life before the Roofing Academy was kind of on a snowball effect. It had started from when I left college and then came home and it kind of just started snowballing. One thing after another was another problem, another problem. Bills at 18, going into debt. You're 18, your life isn't, you're going to ruin your life already. So you got to figure some out. And I figured it out. I got lucky enough that I found GAF and you know they still treat me well to this day. I have my Academy teacher's phone number and I call them up and help him out from time to time, and he helps me out from time to time.We still get along. And it was two weeks of my life that I knew the guy, and he still gives me a call and checks up on me and tries to: How are you doing in roofing? You still in roofing? You still making a name for yourself? You still doing what you said you were going to do? And I am. It's just good to have someone to talk to. Even if you're in this industry for ten years, I guarantee you GAF CARE will probably still give you a call and check on you. That's just what they do.

By Authors GAF Roof Views

April 12, 2024

GAF Sustainability Award winners holding their award.
In Your Community

GAF Celebrates Major Strides in Manufacturing Sustainability

Manufacturing sustainability is a top priority for GAF. In 2022, the company announced its 2030 Planet Goals to "focus on operational improvements, product transparency, and the introduction of circularity in the asphaltic shingle industry."Looking to lead positive change while considering the long-term impact of its business on the planet, GAF identified several goals, including:Diverting 1 million tons of roofing materials from landfills while integrating recycled shingle materials into new shingle productsDiverting 80% of manufacturing waste from landfills, recycling all shingle and TPO scrap that results from the manufacturing process, and recycling or reusing fiberglass mat scraps and coresReducing embodied carbon and operation carbon throughout its manufacturing and operationsAchieving Environmental Product Declarations for its core products, conducting life cycle assessments, and generating 2.5 GW of power from solar roofs in partnership with GAF EnergyMeeting these goals takes time, resources, innovation, and ingenuity, all backed by a team working to build a better world. Every GAF location is striving to meet the company's goals. Looking back on the progress made in 2023, some impressive accomplishments are bringing the company closer to achieving full manufacturing sustainability.Residential ManufacturingThe GAF Mt. Vernon, Indiana, shingle manufacturing plant worked toward achieving sustainable operations through robust recycling efforts. The team established a shingle recycling outlet estimated to divert thousands of tons of asphalt shingles from landfills annually. This has eliminated thousands of dollars in disposal fees and reduced transportation costs.The Mt. Vernon staff found creative ways to keep complex waste materials out of landfills, including working with a local golf course that could take the plant's waste sand. The team implemented an internal recycling program that includes cardboard and packaging materials, increasing its waste diversion score.Commercial ManufacturingAt the Gainesville, Texas, plant that manufactures TPO and Polyiso, team members earned the area's first waste diversion certification for both products' waste streams. They also earned a recycled content certification for each.The plant established a trial program with a plastics recycler to reprocess TPO skin material for reuse in manufacturing new material. Recycling and reusing would divert thousands of tons of waste from landfills and use recycled materials in manufacturing flexible TPO for flashings.The plant also developed a program with a local recycling company that serves as a single source to take its pallets, large cardboard boxes, facers, paper, and plastics.Sustainability All-StarsRecycling and manufacturing sustainability programs wouldn't be possible without the people behind the initiatives. GAF is proud to spotlight these individuals who went above and beyond to meet the company's sustainability goals.Ben AnselmanAs part of the Mt. Vernon team, Anselman was critical to starting the plant's core recycling program. He initiated repairs to an existing baler and established a program for recycling the super sacks. His creativity sparked the partnership with the local golf course to divert aggregate waste from landfills. In addition, he was the champion for the shingle recycling outlet project and repurposed an existing compactor to reinstate a cardboard recycling initiative.Christina Talladira and Amy WilsonThese teammates lead the core recycling program at the Tampa, Florida, manufacturing plant. They worked together to establish aggregate and shingle recycling programs with their local recycling company. Talladira and Wilson consistently look for ways to divert waste streams from landfills. They also handle the administrative needs accompanying these programs, including scheduling loads and tracking waste.Jeremy TisdaleAt the Tuscaloosa, Alabama, plant, Tisdale took the initiative to improve its core recycling program and set up a cardboard recycling program. He also championed a baler trial for glass mat cover and core waste, developing standard operating procedures and a job safety analysis. He was the innovator behind diverting the plant's plastic waste from landfills. He created a program where stretch film and shingle bundle packaging waste is saved in Gaylord boxes and then baled whenever the plant has downtime.Pete WeyrensIn Gainesville, Texas, Weyrens is the champion behind the plant's recycling efforts, establishing relationships with the local recycling company. He also organized the flexible TPO skin material trials. This effort will divert thousands of tons of waste from landfills and use recycled materials to manufacture flexible TPO for flashings.Leslie PeelsAfter the plant in Cumming, Georgia, saw a drop in its year-over-year waste diversion rate, Peels stepped in to turn those numbers around. Leading the effort to separate recyclable materials from regular waste, the Cumming location saw an impressive increase in keeping waste out of the landfill. Peels also set an example in data collection and analysis to keep the plant's sustainability goals on track.TJ Jenkins and Todd WinsteadJenkins and Winstead represent the TPO team at the Mt. Vernon manufacturing plant. Working together, they used their knowledge and experience in the TPO manufacturing process to help earn the plant's recycled content certifications. They also found a way to divert calcium chloride from local landfills and continue to work closely with the sustainability team to support waste diversion efforts.Sustainability PromiseGAF is committed to "Protect What Matters Most," and that includes people, communities, and the planet. Its sustainability promise is an opportunity to invest in a healthy future for everyone. Learn more about that commitment in its sustainability report.

By Authors Karen L Edwards

April 11, 2024

GAF volunteers gather in front of the Ennis, TX plant to celebrate Breast Cancer Awareness.
In Your Community

How GAF Team Members Are Making an Impact in Ennis, Texas

Ennis, Texas, might be best known for hosting the National Polka Festival every year, but it's also home to many GAF professionals who support the community.GAF has been part of the Ennis community for over 45 years, where its footprint has grown to include a research and development center and two manufacturing plants. In addition to the work GAF employees complete onsite, many have used their connections to champion local organizations' efforts. GAF knows how important it is to build resilient, thriving communities, and its continued commitments in Ennis offer proof of what's possible.The GAF Ennis Facility's Tradition of Giving BackWith over 260 employees at the Ennis facility, it has a significant impact on the surrounding area. Many team members have worked there for 30 to 40 years, or more, and are lifelong residents of the city. One of the plants manufactures fiberglass mat rolls, a critical component used in roofing materials, while the other plant manufactures shingles. The shingle plant recently expanded to include recycled asphalt briquettes, which will be used in manufacturing recycled asphalt shingles to divert 300,000 tons of waste from landfills.David Tuttle, Senior Director of Residential Operations at GAF, joined the community in 2004 and in 2012 set out to help his friends and neighbors flourish with increased community engagement. He first joined the board of the Ellis County Children's Advocacy Center and has since expanded his service to other organizations, including two local United Way chapters, and the Ennis Boys and Girls Club.Tuttle's work started a legacy of community leadership. For instance, Joe Glanton, the GAF plant's community engagement ambassador, is now President of the Board of Directors of Greater Ennis United Way. Other GAF associates quickly followed suit, demonstrating their commitment to the community by working on local projects as well as joining the board of the Ennis Boys and Girls Club.Today, the tradition of giving back still runs strong. Many local groups and charitable organizations continue to benefit, and the community keeps growing stronger.GAF Ennis Facility's Community ImpactProviding justice, hope, and healingTuttle was instrumental in setting an example for community engagement. After joining the board of the Ellis County Children's Advocacy Center more than a decade ago, he eventually served as Board President. The nonprofit responds to child abuse and sexual assault reports, providing advocacy, forensic interviews, and mental health services to those affected."Our charge is to provide justice, hope, and healing for every child," Tuttle explains. After serving two years as Board President, and two as Past President, his 12-year tenure on the board is ending, but Tuttle has been working to bring other GAF team members into the organization and maintain support for Ennis's youngest residents.Stepping upGAF team member, Angela Adams, who is also an Ennis Boys and Girls Club board member, serves as a mentor through the Mentors Care program. After a Mentors Care representative was invited to speak at the Ennis plant, three of her colleagues signed up to volunteer as mentors. "I was so impressed by the number of employees who showed up to listen to what Mentors Care had to say," Adams notes.Mentors Care matches struggling high school students with mentors who serve as positive role models to help students manage their day-to-day challenges. The nonprofit recently reported that 100% of seniors in the program graduated, 92% of mentored students achieved a 90% school attendance rate, and 89% of students advanced to the next grade level.Unique solutions for unique challengesMatt Neal, GAF engineering manager, serves as Board President of Runnin' Free Ranch, which serves area veterans, at-risk youth, and individuals with special needs through counseling with horses. The organization is working to change the lives of Ennis residents who face unique challenges.A local US Navy veteran who participates in the program wrote that he was "a prisoner of rage and unending bitterness" after he departed from serving. Though he doubted a horse could help him, he eventually realized that "our therapy sessions have comprised of laughter, tears, frustration, and a release of tension that I've never experienced before."Making a direct impact when it's needed mostJoe Glanton has been involved in the evolution of many community organizations, including serving as a board-level leader for the Ennis CARES organization. Founded during the COVID-19 pandemic, Ennis CARES was developed to help community members with non-emergency needs, including food, health care, and other services. Glanton notes that "it's a natural extension of our work to be as supportive and active as possible with organizations that have a direct impact on protecting what matters most."Ennis CARES will soon break ground on a new community center and "combat multiplier" for local charities, opening space to house a food bank and provide services such as health care for women and seniors.Disaster ResponseRandy Brumley, GAF mat plant Production Process Manager, met Team Rubicon—a disaster response organization—when they visited the Ennis plant. He instantly decided to become a greyshirt volunteer alongside several other team members.Brumley wrote about his first operation, where he responded to Houston neighborhoods affected by Hurricane Harvey. "Team Rubicon is a diamond class organization held together by volunteers—veterans and civilians—and respect at its core," he explains. "For anyone who has the chance, I would say: Step into the arenal!" Brumley has been a part of the Ennis community, and a GAF employee for over 40 years, and also serves as a member of the Ennis Boys and Girls Club.Becoming Part of the CommunityTuttle shares that he and his teammates appreciate that GAF affords them the flexibility and opportunity to give back to their communities. "It's exciting that GAF provides the support and encouragement to go and serve," he says. "We owe it to our communities; we're really blessed and privileged with our jobs and careers and the benefit to go volunteer. Everyone has the ability to go and find a place to serve."With a total of 34 manufacturing locations spread throughout 26 communities across the US, GAF and its team members are well positioned to change lives and help build resiliency nationwide. Curious to learn more about joining the GAF team? Explore the available career options and opportunities to get involved.

By Authors Karen L Edwards

April 09, 2024

Don't miss another GAF RoofViews post!

Subscribe now