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Commercial Roofing

Best Use Cases for Silicone Roof Coatings

By Karen L Edwards

October 07, 2020

A roller applying silicone roof coating

Silicone roof coatings are known for their ability to provide excellent UV, water, and weathering resistance. This can make them a great choice for many low-slope roofs.

Here's a look at the strengths of silicone roof coatings and the use cases they're best suited for.

The Benefits of Silicone Roof Coatings

Silicones are high-performing polymers that can be found in many consumer products, paints, and coatings. Silicone-based roof coatings are a popular choice for low-slope roofs because they:

  • Are stable at a wide range of temperatures
  • Help protect against leaks caused by ponding water
  • Provide resistance to biological growth like algae and mold
  • Adhere well to many different substrates
  • Can provide a reflective coating if white or light colors are selected

Types of Silicone Roof Coatings

Silicone roof coatings are available in a few different formulations, including formulations with high solids.

High solids coatings have fewer solvents in their formulation, meaning the product will experience less evaporation during installation. It might be slightly more expensive than other formulations, but because of the high solid formulation, you'll probably use less product overall to achieve your desired dry mil thickness.

Solvent-based silicone coatings may be desirable because the incorporation of solvent in the formulation can result in faster drying times than water-based coatings. They can also be stored and applied at lower temperatures without risk of freezing. However, the solvents are highly volatile, so care must be taken to keep vapors away from sparks or flames to avoid combustion. Solvents can also be odorous, so additional steps may be required to ensure the safety of workers and building occupants. it is important to close building air intakes during installation.

Use Cases for Silicone Roof Coatings

High Solids Coatings

High solids coatings may be a suitable choice for low-slope roofs in high-moisture areas. The coating will perform well even in roof areas that are subject to ponding water.

High solids silicone coatings can also be installed with minimal disruption to building occupants. With low VOC content, they could be an ideal choice for high-occupancy buildings like healthcare facilities, nursing care facilities, daycare centers, and schools.

High solids silicones can be used over many types of existing roofs, including metal, structural concrete, single-ply membranes, and asphalt roofs. They are also a good fit for installing over polyurethane foam on new or existing roofs.

Solvent-Based Coatings

Solvent-based silicone coatings also perform well in areas where high moisture and humidity are present. The evaporation rate of the solvents is not affected by the amount of moisture in the air.

Solvent-based coatings are a versatile option because they can be installed in temperatures ranging from 40 degrees Fahrenheit (4.44 °C) to 110 degrees Fahrenheit (43.33 °C). They also enable flexibility in their application method, allowing for use of a brush, roller, or sprayer.

When to Consider Other Coating Types

Keep in mind that silicone coatings, whether solvent-based or high solids, form a slick surface that might not be suitable for roofs with high foot traffic. They do not resist dirt pickup as well as other types of coatings and may require cleaning to maintain reflective properties.

If you are unsure which type of roof coating will be the right fit for your roofing project, GAF can point you in the right direction. Or, you can learn more about the roof coating options available to you.

About the Author

Karen L. Edwards is a freelance writer for the construction industry and has a passion for roofing, having worked in the industry for 20 years.

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The Advantages of Silicone Roof Coatings

As a commercial roofing contractor, you're responsible for choosing the right materials for each job. But with so many options available, making a decision can be difficult.Increasingly, industry professionals have been turning to silicone roof coatings for their strength and durability. These coatings can help extend the life of a structurally sound roof and potentially save property owners time and money by delaying a full reroof. Plus, their restoration properties work great with most commercial roofing systems, like EPDM, built-up, bitumen, and metal roofs. What Are Silicone Roof Coatings?Silicone coatings are high-performance, waterproof protective roof coatings. Adding this coating to a structurally sound roof can help extend the life of the existing roof. Silicone is inorganic, so it can maintain its properties in inclement weather conditions. It's also flexible and can absorb most normal roof movement to help avoid cracking and losing its protective features.Benefits of Silicone Roof CoatingsIn addition to flexibility and extending the life of the existing roof, silicone coatings offer several other benefits. Laura Soder, senior product manager for liquids and coatings at GAF, explains that GAF silicone coatings are designed to help protect against leaks and provide related advantages.UV Ray ProtectionThe major benefit of silicone coatings is ultraviolet (UV) ray protection. "GAF silicone is formulated with titanium dioxide, providing exceptional UV stability and high solar reflectance," she says. This UV protection can help lower roof top temperatures, which may translate into more efficient operation of roof top units.Cost-EffectiveSilicone coatings are cost-effective solutions that can help delay the cost of materials and labor needed to replace the entire roof. They work great with most commercial roofs and pair exceptionally well with metal roofs.Restores and Helps Extend the Life of the Existing RoofSoder notes that silicone coatings adhere well to metal roofs, making them an excellent way to extend the service life of metal roofs. Before application, brush away light rust or spot-treat heavier rust. "There are a lot of metal roofs out there, and for those that are structurally sound and require only moderate restoration, you can easily add years to the roof's life by coating them with silicone," she says.Moisture-ResistantSilicone coatings are also known for their moisture-resistant capabilities. Since silicone is inorganic, it resists degradation in areas that pond water, making it an ideal choice in areas that experience rain or snow.Works in Hot and Cold WeatherSilicone has a wide temperature application range. Because it doesn't contain water, you can apply it at lower temperatures than acrylic and other roof coatings. It provides a monolithic, seamless waterproofing layer over existing metal roofs. Silicone will also flex with metal in cold and hot weather.How Silicone Compares to Elastomeric CoatingsCompared to acrylic and other elastomeric roof coatings, silicone has some advantages.Acrylics are water-based protective coatings with UV resistance —but they shouldn't be installed where there is ponding water, as they can break down and start delaminating. Silicone is a moisture-cure material, meaning it reacts with moisture in the air and cures to a finished film.Soder explains that both materials are flexible and appropriate for use over metal. But if you have any standing water, acrylic isn't the best choice. "While silicone is more expensive, it typically weathers at a much slower rate than other coatings," she says. That said, one of silicone's drawbacks compared to other elastomeric roof coatings is that it's slippery when wet.Navigating Installation and ApplicationWhile silicone coatings can help extend the life of an existing roof, Soder notes it's best to install the coating before the end of the existing membrane's service life.Since leaks tend to happen at roof seams, add silicone sealant to these areas. Sealants are formulated differently than coatings—they use different silicone polymers, giving them a heavier body and stronger build. Silicone sealants are formulated for high-stress areas and can help absorb movement at critical points in the roof. They work hand in hand with a silicone coating to protect the roof.Before you apply any coating, ensure the roof is clean, dry, and sound. "Clean means free of contaminants, dust, oils, leaves, and other debris," Soder says. 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Some coatings, like GAF Unisil Silicone, require two coats, while others such as the GAF High Solids Silicone may need just one.Understanding Maintenance Needs and LongevityMaintaining a silicone roof coating is essential. Addressing issues before they become problematic can help minimize the cost of repairs and maximize the service life of the coating.As the roof flexes over time, issues with the seams might develop. A good rule of thumb is to get a roof inspected every six months. Applying a silicone sealant can help address areas with leaks or cracks. Silicone sealant is UV stable and doesn't require a top coat, according to Soder.Adding Silicone Roof Coatings to Your ToolboxWith many benefits, silicone roof coatings should be front of mind when planning roof restoration projects. And with several options available, you can choose the best type for each roof you work on. Have more questions about roof coatings? 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By Authors Mark Soto

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Roof Insulation: A Positive Investment to Reduce Total Carbon

Have you ever thought about building products reducing the carbon dioxide emissions caused by your building? When considered over their useful life, materials like insulation decrease total carbon emissions thanks to their performance benefits. Read on for an explanation of how this can work in your designs.What is Total Carbon?Total carbon captures the idea that the carbon impacts of buildings should be considered holistically across the building's entire life span and sometimes beyond. (In this context, "carbon" is shorthand for carbon dioxide (CO2) emissions.) Put simply, total carbon is calculated by adding a building's embodied carbon to its operational carbon.Total Carbon = Embodied Carbon + Operational CarbonWhat is Embodied Carbon?Embodied carbon is comprised of CO2 emissions from everything other than the operations phase of the building. 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The "cradle to gate" approach neglects the remainder of the embodied carbon captured in the broader "cradle to grave" assessment, a more comprehensive view of a building's embodied carbon footprint.What is Operational Carbon?Operational carbon, on the other hand, is generated by energy used during a building's occupancy stage, by heating, cooling, and lighting systems; equipment and appliances; and other critical functions. This is the red CO2 cloud in the life-cycle graphic. It is larger than the gray CO2 clouds because, in most buildings, operational carbon is the largest contributor to total carbon.What is Carbon Dioxide Equivalent (CO2e)?Often, you will see the term CO2e used. According to the US Environmental Protection Agency (EPA), "CO2e is simply the combination of the pollutants that contribute to climate change adjusted using their global warming potential." 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You can utilize these carbon savings to offset the carbon use in other areas of the design, like aesthetic finishes, where the decision to use the product may be discretionary but desired.When designing buildings, we need to consider the whole picture, looking at building products' embodied carbon as a potential investment yielding improved operational and performance outcomes. Our design choices and product selection can have a significant impact on total carbon targets for the buildings we envision, build, and operate.Click these links to learn more about GAF's and Siplast's insulation solutions. Please also visit our design professional and architect resources page for guide specifications, details, innovative green building materials, continuing education, and expert guidance.We presented the findings in this blog in a presentation called "Carbon and Energy Impacts of Roof Insulation: The Whole[-Life] Story" given at the BEST6 Conference on March 19, 2024 in Austin, Texas.References:Architecture 2030. (2019). New Buildings: Embodied Carbon. https://web.archive.org/web/20190801031738/https://architecture2030.org/new-buildings-embodied/ Carbon Leadership Forum. (2023, April 2). 1 - Embodied Carbon 101. https://carbonleadershipforum.org/embodied-carbon-101/

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Minimizing Disruption When Repairing Roofs on Schools and Hospitals

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You may be able to complete school projects when school is out of session, but that isn't always the case if a leak or storm damage occurs.The best (and most proactive) way to minimize disruption is to use durable, long-lasting materials, as this reduces the number of times crews need to work on the roof.Single-Ply MembranesGrant recommends a robust single-ply membrane or a system with some redundancy, such as a multi-ply modified bitumen. She also suggests leveraging a hybrid system, composed of a multi-ply modified bitumen system with a single-ply top sheet for reflectivity.Cover and Substrate BoardsFor resiliency against noise-causing conditions such as hail and foot traffic, Grant suggests using cover and substrate boards. Cover boards are installed on top of the insulation and provide sound insulation, while substrate boards are installed directly on the roof deck under the insulation."If you have a really noisy location, and you want to keep people inside from hearing a lot of disruption, having cover and substrate boards included in the system can be really important," says Grant.Adhesives and FastenersAnother change you can make to reduce disruption is using adhesive to attach roofing products instead of mechanically fastening them. This helps avoid the noise from driving fasteners into the roof deck—and enables a faster installation.Grant notes that, depending on the FM and wind ratings required, it may be possible to adhere all the system components, including the insulation, cover boards, and membrane. An adhesive like GAF EverGuard® TPO Quick-Spray Adhesive can effectively adhere TPO and PVC roofing materials. The product has a high initial tackiness, allowing for faster installation than traditional adhesives. You can also opt for self-adhering products (vapor retarder, pipe boots, TPO roofing, etc.), which can further reduce installation time by eliminating adhesive application from the process.Materials That Shorten Project TimelinesA creative and efficient way to minimize disruption at school and hospital job sites is to reduce the time crews are on the roof. By taking advantage of time-saving materials, you can reduce the risk to workers and occupants, increase productivity, and ultimately take on more work.In addition to the Quick-Spray Adhesive, GAF offers several materials designed to cut installation time and labor:Wider rolls of TPO (12 feet instead of 10 feet) can help crews to spend less time installing systems on wide-open roofs.Insulation installation is easier with lightweight Ultra HD Composite Insulation, and it eliminates the need for one full application of adhesive in adhered systems.TPO self-adhered membrane can cut installation time by as much as 60% compared to installation using traditional bucket and roller adhesives.Experienced Support That Streamlines WorkIn addition to product and material selection, you can minimize disruptions by having GAF professionals from the Tapered Design Group help design the tapered insulation system. These professionals can help you with a variety of services, such as:Tapered insulation designTapered insulation Inventory management and orderingBudget friendly alternativesTapered insulation systems are designed to improve the drainage slope on roofs with substrate damage or without enough slope. The tapered design team at GAF "balances suitable slope with the least amount of material," Grant says. "To help with saving money, saving material, and saving time."This group designs tapered insulation systems that can be loaded and labeled strategically to minimize material handling and time spent looking for and transporting materials. Products are bundled by roof area, and a color-coded plan distinguishes areas for each bundle. Materials are precut and specifically designed for each project.Additional Tools to Save Time and LaborTwo other GAF tools can help you reduce the time spent on projects: GAF QuickSite™ and GAF QuickMeasure™.GAF QuickSite™GAF QuickSite™ provides the information you need before approaching a potential customer. It gives you a snapshot of local codes (important if you're working in an unfamiliar location), a 10-year wind and hail history, historical photographs documenting changes over time, and parcel information (including size and sales dates).GAF QuickMeasure™GAF QuickMeasure™ provides complete roof measurements including parapet wall lengths, heights and widths to help create estimates, past views showing how a roof may have changed over time, grid-lined paper for buildings with predominate pitch of 0 or 1, and a DXF file output for CAD.With the help of GAF QuickSite™, GAF QuickMeasure™, and the Tapered Design Group, you can confidently give your healthcare clients and school customers accurate estimates for suitable roofing products to meet their needs. These tools can also minimize disruption to building occupants and help building owners select durable, long-lasting products that will protect their investments for years to come.Leveraging GAF Professionals' ExperienceWhen working on schools, hospitals, and other important institutions, you're working to satisfy not only your clients but the individuals visiting these locations. By minimizing disruption, you can help ensure everyone involved experiences minimal disruption while you complete the project.For more insight into time- and labor-saving products and services, explore GAF School Rooftop Resources.

By Authors Dawn Killough

August 29, 2024

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