RoofViews

Your Home

How to Measure a Roofing Square

By Annie Crawford

March 23, 2021

man on ladder measuring roof with level

Starting a new roofing project can introduce homeowners to many roofing-specific terms, and one of the first you're likely to come up against is "roofing square." Measuring in squares is unique to the roofing industry—for homeowners, understanding how these measurements work can be an unfamiliar but vital part of planning for your roof repair or replacement.

What Is a Roofing Square?

In roofing, one square equals 10 X 10 ft., or 100 sq. ft. This unit of measurement determines how many shingles you'll need for every 100 sq. ft. of rooftop. As you prepare for your roofing project, you'll use squares to determine the amount of roofing materials you need, from asphalt shingles down to the underlayment.

How to Calculate a Roofing Square

Before beginning, make sure you can safely access your roof—if you can't, contact a roofing professional for help.

Grab your measuring tape, level, pen and paper, roof safety equipment, and your ladder. With these in hand, you can measure your roof in five simple steps.

  1. Determine the number of planes. Your roof is made up of planes. If you have a flat roof, it has one plane. If you have a simple gable roof, it has two planes. The more architectural details your roof has, the more planes you will have to measure.
  2. Measure each plane. Find the length and width of each plane. Then, multiply those two numbers together to find the square footage of that plane. For example, a 35 ft. X 36 ft. plane = 1260 sq. ft.
  3. Find the total of all the planes. Add the square footage for each roof plane into one total. 1,260 sq. ft. + 1,260 sq. ft. = 2,520 sq. ft.
  4. Divide to find the squares. To find how many squares are on your roof, divide the total square footage of all your planes by 100. In our example, the total was 25.2 squares — 2,520 sq. ft. divided by 100.
  5. Remember the roof slope. Roof slope indicates how steep your roof is and may increase the number of squares of materials you need. Roof slope is calculated by determining how many inches a roof rises vertically for every 12 inches it extends horizontally. For example, if that vertical rise is 4 inches, the slope is 4:12.

You can use an online shingle calculator or roof slope calculator to help run the calculations. Once you know the total number of squares you want to cover, consider adding up to 10% in overage to account for error and installation.

Pro tip: don't rely on your home's square footage to determine roof size. Your roof's overhangs, architectural details, and slope all increase its size. For example, a 2,200 sq. ft. home (22 squares) might have a 3,500 sq. ft. roof (35 squares).

How to Calculate Number of Roofing Shingles

Fortunately, you don't have to make a haphazard shingle estimate when planning for your roofing project: your roof size and chosen shingle type will guide the purchase process.

Shingles are sold in prepackaged bundles, not individually. Roofing manufacturers take the guesswork out of how many bundles you need per square—it's listed in the specifications of each shingle they make. The specs for any given shingle will tell you how many bundles make up a square, how many shingles are in a square, and even the approximate number of nails you'll need per square.

Often, three bundles of prepackaged asphalt shingles make one square, as is the case with the Timberline® HDZ™ Shingles. That said, the number of bundles you need can vary depending on shingle design. For example, five bundles of architectural asphalt shingles with artisan-crafted shapes, such as the Grand Sequoia® Shingle, cover one square. Once you know the number of squares of material your roof needs, check the shingle manufacturer specifications so you get your hands on exactly what you need.

If you're still deciding on the perfect shingle for your roof, play around with the GAF VirtualRemodeler. The free online tool helps you envision how different shingle colors and styles would work with your home's style. Be sure to keep local building codes in mind as you weigh your shingle options..

Ready to get rolling? Before you begin, take the appropriate safety precautions for getting onto your roof. If you can't safely access your roof, reach out to a local contractor certified by GAF.*


*Contractors enrolled in GAF certification programs are not employees or agents of GAF, and GAF does not control or otherwise supervise these independent businesses. Contractors may receive benefits, such as loyalty rewards points and discounts on marketing tools from GAF for participating in the program and offering GAF enhanced warranties, which require the use of a minimum amount of GAF products.

About the Author

Annie Crawford is a freelance writer in Oakland, CA, covering travel, style, and home improvement. Find more of her work at annielcrawford.com.

Related Articles

A roofer unloads shingles on to the roof of a house prior to installing them
Your Home

How to Find a Roofer You Can Trust

Whether it's time for a new roof or a repair, you'll need a roofing contractor to help you make the right choices for your home. But if you haven't hired a roofer before, you may not know what to look for.From referrals and licenses to manufacturer certifications, here's how to find a roofer you can trust with your home.Ask for Recommendations or ReferralsOne of the best ways to find a roofer is to ask people you trust for recommendations. If you have a friend, relative, or neighbor who has had their roof repaired or replaced in the last few years, ask them who they used.Many communities and neighborhoods also have local Facebook groups or message boards. You can use these resources to get recommendations for experienced local contractors—and find out what roofing companies you should avoid.Look for Manufacturer CertificationsSome roofers become certified by one or more roofing manufacturers.If a contractor is part of a manufacturer's certification program, the contractor is more likely to be familiar with the manufacturer's products and may be eligible to offer enhanced warranties. Each program has it's own requirements so you should check the manufacturer's website to see what a particular certification entails.For instance, GAF Master Elite® contractors must be insured and licensed in states where they operate (if required). GAF also considers factors such as years of roofing experience, credit rating and overall standing with the Better Business Bureau. GAF Master Elite® contractors are the only roofing contractors who can offer the GAF Golden Pledge® Limited Warranty* with up to 30 years of workmanship coverage on qualifying roofing systems.In addition to certification programs, manufacturers may recognize certain contractors with awards. For example, GAF Master Elite® President's Club award-winning contractors demonstrate continued excellence in three key areas: performance, reliability, and service. Over the course of the prior year, award winners must have installed a minimum number of roofing systems that qualify for the highest warranties.Review the Contractor's Online ReputationWhether you first connect with a contractor through a recommendation or a quick Google search, do some online research to ensure you find a roofer you can trust.Read company reviews, see what customers say on the contractor's social media pages, and visit the contractor's website for details on their products, services, and experience. You're looking for a company with a good track record and reputation. Once you've gathered all this information, you'll be able to make a more educated decision.Check the Contractor's License and InsuranceYou want to work with a licensed contractor (in states where licensing is required). If your state requires roofers to be licensed, run a license check on your state's Department of Consumer Affairs or business licensing website.Also, make sure the contractor is insured with coverage for all their employees and subcontractors. This will help protect you if a worker injures themselves on your property or damages your home while working.Visit the Better Business BureauThe Better Business Bureau (BBB) has a database of information about businesses in different industries across the country. You can search by business name or business category (i.e., roofing), and then enter the name of your town or zip code to find companies that have BBB accreditation or a high rating. Some listings also feature customer reviews, which is another way to determine whether you want to work with a particular roofer.Choosing the Right Roofing Contractor for Your HomeWhen you find a roofer you can trust to work on your home, price shouldn't be your only consideration. Experience, quality of service, and reputation also matter.Take the time to research potential roofers. Ask for recommendations, look for contractors with manufacturer certifications, and check your state's contractor registration or licensing site and the BBB website. Following all these steps can help you pick the right roofing company for your job.Once you've selected a contractor, it's time to get ready for your roofing project to begin. Check out this checklist for your next roofing project for next steps.*Contractors enrolled in GAF certification programs are not employees or agents of GAF, and GAF does not control or otherwise supervise these independent businesses. Contractors may receive benefits, such as loyalty rewards points and discounts on marketing tools from GAF for participating in the program and offering GAF enhanced warranties, which require the use of a minimum amount of GAF products. Your dealings with a Contractor, and any services they provide to you, are subject to the Contractor Terms of Use. Visit www.gaf.com/gaf-contractor-terms-of-use for details**Eligibility requirements, coverage, terms and restrictions apply and vary based on the enhanced warranty and products installed. For details and to view fullGolden Pledge Limited Warranty visit https://www.gaf.com/en-us/for-homeowners/warranties. Visit gaf.com/LRS for qualifying GAF products.

By Authors Dawn Killough

January 25, 2024

Contractor carrying a box of GAF Cobra Rigid Vent 3
Your Home

Why Proper Attic and Roof Ventilation Matter to Your Home

You may not automatically consider attic and roof ventilation when replacing your home's roofing system. However, it's a key part of the process. Here's why roof ventilation matters and the role proper attic ventilation can play in your roofing system. The Importance of Proper Attic Ventilation Your home generates moisture every day: cooking, showering, and even normal breathing all create moisture that can find its way up to your attic. Without proper attic ventilation, that moisture has nowhere to go. Once trapped, it can damage your interior spaces and reduce the effectiveness of your attic insulation. It can even contribute to the overall deterioration of your roof system and structural supports over time. Ventilating your attic space allows that interior moisture, along with hot air, to be exhausted near the top of the roof through ridge vents, roof louvers, powered vents, or other exhaust vents. Fresh air can also enter the attic along the soffits and eaves. This is referred to as intake ventilation. In order for that moisture and heat to escape through the exhaust vents, fresh, cooler air must be allowed to enter the lowest portion of the attic, at or near the soffits or overhangs. The key to effectively ventilating your attic lies not only in ensuring you have enough attic ventilation for your particular home, but finding the proper balance of intake versus exhaust ventilation. The U.S. Housing Authority recommends a minimum of at least 1 square foot of attic ventilation, evenly split between intake and exhaust, for every 300 square feet of attic floor space. This involves a bit of math, so the experts at GAF have developed a simple-to-use ventilation calculator tool to help you figure out the proper amount of ventilation. Be sure to consult your local building codes for attic ventilation requirements or ask your roofing contractor. Benefits of Proper Attic Ventilation Though they may vary depending on your area and the season, there are some significant benefits to having a well-ventilated attic. Helps lower attic temperature. Proper attic ventilation supports a strong roof system. A balanced and effective attic ventilation system helps exhaust superheated air from the attic, which could save your air-conditioning system from having to work as hard in the summer. Reduces the risk of ice dams. In colder climates, proper ventilation can help prevent ice damming. Allowing cold winter air to pass through the attic keeps your roof's temperature cooler, and helps prevent the cycle of snow melting and refreezing that can cause damaging ice dams. Helps protect your roof system. Heat and moisture buildup can add stress to the shingles and other parts of your roof system, potentially causing premature deterioration. A balanced* and effective attic ventilation system allows cooler, fresh air to enter the attic, forcing out superheated air, which helps protect your roofing system. What to Ask Your Roofing Contractor Most contractors today are installing some type of attic ventilation, but in some cases, they may not be installing the proper amount for the job or they may only be installing exhaust vents, such as a ridge vent. In other cases, they may simply not be installing enough to meet the necessary balance between the two—intake and exhaust. There isn't one universal solution, as every home is designed and built differently. Here are some questions to ask your contractor about your roof ventilation. Based on the size of my attic space, do I currently have enough ventilation? Do I have both exhaust ventilation at or near the ridge of my roof, and intake ventilation at or near the overhang/soffit area? Is there enough ridgeline on my roof to install the right amount of exhaust ventilation? If not, what other types of exhaust vents do you recommend (i.e., power vents or roof louvers) to provide the needed amount of exhaust ventilation? Are my existing overhang/soffit vents clogged by paint or covered with attic insulation? If I don't have any intake ventilation or enough ventilation at my overhang/soffit area, can it be added? Would you mind looking at my attic insulation? Is it in good condition, and does it properly cover the entire attic floor? If you're in need of roof repairs or replacement, reach out to a contractor certified by GAF ** in your area. Be sure to ask about proper ventilation and the options available to ensure that your roofing system will deliver the best performance and protection for your home. *Always have a balanced attic ventilation system. In no case should the amount of exhaust ventilation at or near the ridge exceed the amount of intake ventilation at or near the soffit. See www.gaf.com/ventcalcalculator for details. **Contractors enrolled in GAF certification programs are not employees or agents of GAF, and GAF does not control or otherwise supervise these independent businesses. Contractors may receive benefits, such as loyalty rewards points and discounts on marketing tools from GAF for participating in the program and offering GAF enhanced warranties, which require the use of a minimum amount of GAF products.

By Authors Karen L Edwards

January 25, 2024

Carter Work Project team in front of house
In Your Community

Teaming Up to Build Skills and Shelter for the 2023 Carter Work Project

Work is getting underway in Greater Charlotte, North Carolina, as GAF supports Habitat for Humanity with the 2023 Jimmy and Rosalynn Carter Work Project. The five-day build event began in 1984 when former President Jimmy Carter and former first lady Rosalyn Carter led a group of Habitat for Humanity volunteers to New York, building alongside 19 families in need of safe, affordable housing. For 36 years, the Carters have worked side by side with professional builders and volunteers at locations around the world to build and raise awareness of affordable housing.From October 1st - 6th, more than 750 volunteers will cooperatively build 27 safe, affordable homes in Charlotte, where the homeownership rate of 26% falls far below the county average of 57%. A strong contingent of GAF team members will comprise the volunteer workforce, and the company is lending support in several other ways.Working Together to Build Better CommunitiesSince 2011, GAF has proudly partnered with Habitat for Humanity. For the 2023 Carter Work Project, GAF donated the roofing materials for all the homes built, offered training prior to the event, and will provide leadership while the work is being completed."We're focused on helping build more resilient communities, by making workforces, affordable homes, and ultimately families more resilient," says Jeff Terry, GAF vice president of corporate social responsibility and sustainability.The Carter Work Project has touched thousands of lives over the last few decades and means so much to all involved. "To know that we're making a small dent in the housing affordability crisis is something very near and dear to my heart," Hailey Von Dross, youth and young adult engagement coordinator for Habitat for Humanity of Charlotte, shared at a recent training session in Charlotte.Helping Leaders Grow While Doing GoodIn July, the high heat was no match for the great attitudes at the two-day, hands-on, on-the-roof training hosted by GAF CARE (Center for Advancement of Roofing Excellence) to prepare for October's construction work. The house and crew leaders who attended the GAF CARE training will use the roofing skills they learned to guide Carter Work Project volunteers and workers in proper shingle installation.Training these building leaders was a "really exciting opportunity" for the GAF CARE team, says Terry. "It ultimately gives them the tools to make these homes more resilient for the partner families who will be working alongside all of us and ultimately getting the keys to these homes."The GAF CARE training can also help shape future community leaders. Rachel Hurst, an AmeriCorps volunteer working with Habitat for Humanity, says, "GAF is here helping us learn the proper way to shingle a roof. It's actually really cool. It's really rewarding and shows volunteers that they have the ability to create something."The transformative power of these homes should not be underestimated. For example, Adam Hunter, new construction field manager for Habitat for Humanity of Charlotte, took a break from the GAF CARE training to reflect on his own journey with Habitat for Humanity. When he was five years old, his family bought a Habitat for Humanity home."That is still our family home," Hunter shares. "It's still the home we go home to every Christmas." Now, decades later, while helping prepare for the October 2023 build, he says, "When I look around, I see not only the work that's being done today, but I see the path that these new homes can set these families on."Honoring the Carters' Legacy of Service and ShelterThe 2023 Carter Work Project is particularly exciting, as construction is kicking off after a three-year hiatus between 2019 and 2022 due to the pandemic. This year's event also honors Jimmy and Rosalynn Carter, as it is the first project the couple won't participate in after retiring in 2019, following decades of humanitarian global service.Country music super-stars Garth Brooks and Trisha Yearwood will host the build event in Charlotte—while also celebrating their 13th year working on the Carter Work Project.Whether celebrities or volunteers, everyone is equal as they gather for this great event. The GAF CARE training is just one of many contributions from all those involved with the goal of building more resilient families and communities. That's why GAF is proud to support the Carter Work Project year after year."A good roof system means that a homeowner won't have to worry," Von Dross noted during the roofing training event in July. "It's quite literally a roof over their head, and we're making sure that roof will be strong and durable and won't leak."Getting Involved and Making a DifferenceWhile preparations are currently underway for the 2023 Carter Work Project, it's never too late to partner with your local Habitat for Humanity affiliate and support building safe and secure homes in partnership with families in your community. The GAF Habitat for Humanity Program works year-round to improve affordable housing and community resiliency. As part of the program, GAF Master Elite® and GAF Certified™ Contractors* donate their time and services to install GAF roofing materials donated by the company (complete with a GAF System Plus Ltd. Warranty).To learn more about how GAF is building resilient communities, read about their Community Matters initiative. There's always an opportunity to give back and help improve the quality of life of others—and as the Carters know, every bit helps.*Contractors enrolled in GAF certification programs are not employees or agents of GAF, and GAF does not control or otherwise supervise these independent businesses. Contractors may receive benefits, such as loyalty rewards points and discounts on marketing tools from GAF for participating in the program and offering GAF enhanced warranties, which require the use of a minimum amount of GAF products. Your dealings with a Contractor, and any services they provide to you, are subject to the GAF Contractor Terms of Use.

By Authors Annie Crawford

January 25, 2024

Lorem ipsum dolor sit amet