Can You Put New Shingles over Old Shingles?

GAF Timberline HDZ® Reflector Series Shingles come in rich, vibrant colors, giving homeowners attractive color options that can be used to comply with the Cool Roof Requirements of Title 24 and the LA County Green Building Standards Code.*Here's why you may want to add these shingles to your business offerings, especially if you work in California.Timberline HDZ® RS ShinglesA few features make these shingles stand out.Meeting California Code ComplianceIn California, residential roofs must meet solar reflectance requirements because they are mandated by California's Building Energy Efficiency Standards Title 24, Part 6 and Los Angeles County Green Building Code. Both codes set a minimum reflectance rating known as the solar reflective index (SRI), which measures a material's ability to reflect sunlight and heat. The lower the SRI value (from 0 to 100), the hotter a material becomes in sunlight. The higher the value, the cooler the material. Shingles with a higher SRI help reduce temperatures by reflecting sunlight which can help reduce the cooling load.The new Timberline HDZ® RS Shingles provide solar reflectance that complies with both Title 24 and the Los Angeles County Green Building Code.Title 24California's Title 24 covers the entire state, unless local requirements are stricter, providing cool roof requirements for residential and commercial buildings based on their locations within 16 climate zones. For residential buildings (new construction), climate zones 1 through 9 and 16 have no cool roof requirements. Climate zones 4, and 8 through 15 require cool roofs for new and reroof applications when more than 50% of the roof is removed.If shingles don't meet the required SRI, alternative paths to compliance include using a radiant barrier, airspace, or additional attic insulation.Los Angeles County Green Building CodeThe Los Angeles County Green Building Code's Cool Roof Ordinance covers buildings in the county and prescribes SRI values depending on the type of building (low-rise residential, high-rise residential and hotels/motels, and nonresidential) and roof slope. High-slope (more than 2:12), low-rise residential roofs must have an SRI of 20 or more. Exceptions apply to roof repairs or replacements where less than 50% of the roof is removed, additions of less than 500 square feet or less than 50% of the total roof area, and green roofs.Selling Points for California HomeownersWhen working with property owners in California and Los Angeles County, you can highlight the following selling points of Timberline HDZ® Reflector Series Shingles.Potential Savings on Cooling CostsReflective roofing may help decrease a roof's temperature and cooling load, which has the potential to lower cooling costs.****StyleTimberline HDZ® RS Shingles provide the darkest highly-reflective shingle available, Charcoal, thanks to EcoDark® granules. They also feature GAF's High Definition® color blends for dimensional, wood-shake look.Peace of MindHomeowners can enjoy heightened confidence when choosing Timberline HDZ® RS Shingles because they come with a Lifetime Limited Warranty***** against manufacturing defects and a 25-year StainGuard Plus™ Algae Protection limited warranty.**Enhancing Homes' AppealHomeowners can rest assured that the new Timberline HDZ® Reflector Series Shingles offer the durability of GAF shingles while providing deep, rich color options to match their unique aesthetic.Color OptionsTimberline HDZ® RS shingles feature newly formulated EcoDark® Granules that provide deep rich, dark colors including Charcoal, the darkest highly-reflective shingle color in California, as well as other popular shingle colors that offer color blends for a more dimensional look.Time-Release Algae Fighting TechnologyTimberline HDZ® RS shingles feature GAF Time-Release Algae-Fighting Technology which uses specially engineered capsules that are infused with thousands of copper microsites. This allows the copper to release steadily over time for long-lasting algae fighting power. It's technology so strong, it powers the 25-Year StainGuard Plus™ Algae Protection Limited Warranty.**WindProven Limited Wind WarrantyTimberline HDZ® RS shingles have LayerLock® technology and the StrikeZone™, nailing area like traditional Timberline HDZ® shingles, and are eligible for the WindProven™ Limited Wind Warranty with no maximum wind speed limitation when installed with the required combination of accessories.***Curious to learn more? Visit the GAF Timberline HDZ® RS Shingles product page for more details.*Can be used to comply with the Cool Roof Requirements for steep slope residential buildings of 2022 Title 24, Part 6, of the California Code of Regulations and the Green Building Standards Code of Los Angeles County.**25-year StainGuard Plus Algae Protection Limited Warranty against blue-green algae discoloration is available only on products sold in packages bearing the StainGuard Plus logo. See GAF Shingle and Accessory Limited Warranty for complete coverage and restrictions.***15-year WindProven™ limited wind warranty covers GAF Shingles with LayerLock® Technology only and requires the use of GAF Starter Strips, Roof Deck Protection, Ridge Cap Shingles, and Leak Barrier or Attic Ventilation. See GAF Roofing System Limited Warranty for complete coverage and restrictions. Visit gaf.com/LRS for qualifying GAF products. For installations not eligible for the WindProven limited wind warranty, see GAF Shingle & Accessory Limited Warranty for complete coverage and restrictions.****Energy cost savings are not guaranteed and the amount of savings may vary based on a variety of factors, such as climate zone, utility rates, radiative properties of roofing products, insulation levels and HVAC equipment efficiency.*****Definition of Lifetime: The word "Lifetime" means as long as you, the original owner(s) [or the second owner(s) if coverage was properly transferred during the Smart Choice Protection Period], own the property where the shingles and/or accessories are installed. The Lifetime warranty is applicable only to shingles and accessories installed on a single-family detached residence owned by individuals. For any other type of owner or building, such as a corporation, governmental entity, religious entity, condominium or homeowner association, school, apartment building, office building, or multi-use structure, the length of the warranty is 40 years. See the GAF Shingle & Accessory Limited Warranty, GAF Roofing System Limited Warranty and GAF Golden Pledge Limited Warranty for complete coverage and restrictions.

When developing a new roofing product, it's important to ensure it meets the local roofing codes and requirements in multiple jurisdictions. These standards are often regionally similar, but some may require additional testing or the use of certain raw materials. The product development team at GAF works hard to ensure products meet some of the strictest codes, so they can provide years of protection no matter where they're installed.Jeremiah Hershberger, GAF product manager of residential accessories, recently discussed the role codes and standards play in residential roofing product development, specifically concerning roof vent code requirements.Why Are Product Codes and Standards Important?The main purpose of building codes and standards is to maintain public health, safety, and welfare in all structures. They do this by ensuring that buildings are constructed in such a way as to minimize potential hazards, like fire, structural failure, or storm damage.Building codes exist to improve the safety and livability of buildings. They set minimum requirements for the materials and systems installed, as well as their installation methods. In the US, building codes are upheld and enforced by state, county, and city governments through the permitting and inspection processes.Standards also provide minimum design and performance metrics for products and systems. However, unlike local building codes, they are often universally upheld (nationally or worldwide). Organizations like ASTM International and the National Fire Protection Association are responsible for creating, updating, and communicating these standards. Local building codes often use these standards to set minimums for product and installation quality.How Do Roofing Codes and Standards Affect Product Development?"The goal of product development at GAF is to provide enhanced value for our customers and contractors," Hershberger explains. Ultimately, customers need to be confident in the performance of GAF products and building codes and standards provide a minimum threshold for product performance. Accordingly, they must be taken into consideration when designing products.Codes are prescriptive performance requirements for buildings. They include both the materials used to construct the building and how they're installed. All products used in a particular building must meet the local code requirements for that county or city.Standards are used as bases of comparison. Types of standards include:Testing standards that define methods and minimum acceptable resultsRating standards that provide a way to fairly compare productsDesign standards that set the criteria for specific roof system designsWhen products are developed for use in many geographic areas, they must meet several locations' requirements. For instance, when developing a new off-ridge ventilation product, GAF considers not only how much net free area (NFA) the unit will have, but also the performance characteristics required to meet Florida Building Code, Texas Department of Insurance (TDI), and Miami-Dade standards so the product can be used in areas that adhere to those codes.Why Does GAF Pay Attention to Codes and Requirements?"We want our customers to be confident in the performance of our products not based solely on our word but also on the basis of third-party standards that level set the industry," notes Hershberger. "Codes and testing requirements provide customers with that outside assurance that our products will hold up to the environmental rigors of a specific region or location."For example, TAS-100(A) tests a product's performance in wind-driven rain. The test provides information on how well a ventilation product will perform in such an environment and helps the product development team learn how likely it is that a ventilation product might leak, so we can then mitigate that risk.How Do Codes Affect Product Quality?Codes may specify what raw materials can be used to make a product or how it will perform in certain standardized tests. For instance, ASTM E108 or ANSI/UL790 Class A roofing fire ratings require a high degree of fire protection to the roof deck, which directly affect the materials used to produce these products. Similarly, the UL 2218 Class 4 impact test or the ASTM E330 Uplift Pressure Test show how a product performs under naturally occurring forces (e.g., hail or wind)"GAF strives to find the balance between performance, strength, and ease of installation (or handleability)," Hershberger says. "This often leads us to develop products that use higher grade materials (better performance over time), are simpler to manufacture with fewer points of potential failure, and are easier to install correctly (ensuring repeatability)."How Codes Affect the Development of High-Quality Roof VentsCreating high-quality roof vents and rooftop accessories didn't occur by accident. The GAF development team focuses on roofing codes and requirements through an intentional design process to drive innovation. From product ideation to design, development, and launch, the team ensures products meet or exceed several codes and standards, including:Florida Building CodeSets minimum performance standards for roof construction, such as wind resistance, fire performance, and roof ventilation requirements. Products must be approved by the state before being installed.Miami-Dade CountyThis county in Florida has some of the strictest building codes in the country due to its classification as a High-Velocity Hurricane Zone. Products used there must also be approved by the county as meeting not only Florida Building Code, but the stricter county requirements.Texas Department of Insurance (TDI)Regulates insurance companies and the insurance/claims process in the state of Texas. Roofing products are evaluated based on TDI-adopted building specifications regarding products used and installation methods.Other tests performed to ensure product performance include:TAS-100(A). Determines the water infiltration resistance of a ridge area ventilation system (ridge vents, static vents, turbines, or powered vents).Simulated snow/ice dam. Ice dams can form when a roof is not properly ventilated, leading to snow melting and refreezing along the lower edge of the roof.UL2218 Class 4 impact test. The UL2218 test is a steel ball drop test that evaluates the impact resistance of roof coverings. Class 4 products are shown to withstand the 20-ft drop of a 2-inch diameter steel ball without cracking through significant damage.Ensuring Roofing Products Are Up to the TaskThe product team at GAF routinely performs these tests to ensure roofing materials meet local roofing code requirements. The company then makes the results publicly available, helping customers nationwide rest assured that they can rely on GAF roofing products to perform as expected.For more information on the GAF ventilation products that meet or exceed code requirements, explore the ridge and off-ridge ventilation offerings.

A group of local GAF employees in Burgaw, North Carolina, is making a difference for veterans and the community as a whole. In 2024 alone, Veteran Involvement Brings Excellence (VIBE) has undertaken several initiatives to give back to Burgaw as well as all who live and work there.Bill Price, GAF production supervisor II at the Burgaw manufacturing plant, is the champion for the group. He recently sat down to discuss VIBE's latest projects and share insight into its motivations.What Is the VIBE ERG at GAF?VIBE is an employee resource group (ERG) available for all GAF employees. It focuses on the needs of veterans who work at GAF, provides a place for employees to share their experiences, and helps foster opportunities for them to give back to their communities.Each GAF plant has a VIBE group and facility leader that organizes the team. GAF leadership supports each group and its community efforts.The VIBE ERG's mission is to create a supportive environment for veterans and active duty members from all military branches. The group's core values are integrity, duty, honor, and respect. VIBE provides personal support for members and helps them manage the realities of being a veteran, such as applying for benefits.Each VIBE group can work on or be involved in whatever projects they wish. While their primary focus is to support veterans, they also strive to give back to the local communities they live and work in.VIBE Projects in BurgawThe VIBE ERG at the Burgaw plant meets regularly to discuss the activities they want to get involved in. This year, the group has participated in several projects:17 GAF-employed veterans volunteered for the second annual Habitat for Humanity veteran's build, which GAF donated roofing materials for.Team members participated in a food and clothing drive for a local women's shelter.A local veteran service officer visited the plant to help workers learn about—and gain access to—benefits and resources.In honor of Memorial Day, VIBE provided an opportunity for volunteers to place flags at veterans' tombstones at Coastal Carolina State Veterans Cemetery and Wilmington National Cemetery.That's not all the group has planned for. Future initiatives include hosting Toys for Tots at the plant, adopting a highway in honor of veterans, representing GAF at a booth for the Burgaw Blueberry Festival, and continuing to support local veterans in need.How VIBE Impacts GAF and the CommunityThe Burgaw facility, which employs about 247 people, has one of the largest veteran groups within GAF, totaling 28 members. The facility manufactures ventilation products, such as roof vents, foundation vents, turbines, and heating and cooling ductwork."The group has brought the veterans at the plant together to work toward a common goal and also given everyone the comradery they were accustomed to from when they were in the service," Price says. "I think this has had an impact not only on the employees involved but also on the plant as a whole. All of us involved enjoy being part of the team and giving back to those in need."Price notes that each project the group has been a part of has been well received. "We received many thanks from the families that were receiving assistance from the Habitat build and also from the staff at the local women's shelter during the food and clothing drive," he says. "I have no doubt that as we continue to be involved with more events within the community, it will only get better."Giving Back While Looking AheadGAF believes in giving back to its employees and the communities they work in. VIBE is just one of seven GAF ERGs making a difference in team members' lives and those most important to them.Curious to learn more about the opportunities and culture at GAF? Visit our GAF Careers page.