When Does a Roof Coating Make More Sense than a Roof Replacement?

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. You can use GAF Cleaning Concentrate to power wash your roof.Since silicone is moisture-cure, the roof needs to be dry before applying. Coating over a wet surface can affect adhesion and is often one of the biggest mistakes you can make when installing. You want the coating to start the curing process from moisture in the air, not from moisture on the roof.How to Apply Silicone CoatingsApplying a silicone roof coating involves five steps:Clean any debris off the roof and test that the coating will properly adhere to the surface.Ensure the roof is in sound condition. Repair broken sheet metal, and replace missing or damaged fasteners.Treat all seams and fasteners with silicone sealant like GAF Silicone Mastic. Apply it at 60 mils or 1/16-inch wet thickness with a brush.Use the same sealant on any curbs, penetrations, and drains.Finally, apply the silicone roof coating to the entire roof. 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? GAF technical service reps are more than happy to assist you on your next coating project.

Building owners have a lot to think about when selecting a roof for their commercial property. When it comes to commercial roofs, we have some information to help you understand what factors play a role in the roofing system's success, and its ability to protect the building, people and contents within it.1. ProductsThere are several different types of commercial roofing systems, and each has different benefits. A roofing professional can help building owners decide between the following roofing system types depending on the unique needs of the building:Single-ply: Single-ply membrane systems are the most popular commercial roofing material because single-ply is strong, durable, and provides robust protection against UV damage.Liquid-applied: Liquid-applied roofing systems are also strong and durable, and they're ideal for challenging roofs with a lot of equipment and penetrations. Ensuring flashing integrity and regular membrane cleaning can help extend the life of a liquid-applied roofing system.Modified-bitumen: A typical modified bitumen roofing system consists of two plies of roofing membrane. The membranes contain synthetic rubber which provides greater elongation than some other asphaltic systems. Modified-bitumen systems have a wide range of application methods, and can be hot-mopped, cold-applied, heat-welded or self-adhered.Built-up roofing: Built-up roofs are the oldest of the current roofing technology, and consist of melting bricks of hot asphalt in a large metal kettle and using mops to apply that asphalt in-between a multi-ply BUR system.It is recommended that all components of a roofing system are purchased from the same manufacturer. This helps ensure that the components are designed to work together. It also may make the system eligible for enhanced warranty or guarantee coverage from the manufacturer.2. EnergyThe rise of more stringent energy codes has increased the need for additional roof insulation and increased roof surface reflectivity. Increasing the amount of insulation in the roof and installing highly reflective roofing materials can help improve the energy efficiency of buildings.3. MaintenanceRegular roof maintenance may be required in order to keep your manufacturer's guarantee or warranty in effect.Maintenance programs can also help commercial building owners manage risk. Regular maintenance can help you address minor problems before they become expensive issues, which may ultimately help owners save money long-term.Maintenance staff should perform regularly scheduled roof inspections at all locations to ensure that the roof is still in good shape. Look for dents, tears, ponding water, or other signs of damage. Roof drains should be cleared regularly to ensure that water is allowed to drain unimpeded. Regular inspections and maintenance allow potential problems to be discovered early, before they cause other damage.Property maintenance companies and building owners can talk with manufacturers such as GAF to learn more about proper roof maintenance. Click here to get started.4. Warranty/GuaranteeA good warranty or guarantee program is one of the top reasons commercial building owners may choose a particular roofing system. Building owners want to know that they can count on the manufacturer to address any covered issues that may arise. Many roofing manufacturers offer warranties or guarantees for building owners that have no dollar limit on covered repair expenses.GAF offers several commercial roof system guarantees and warranties, ranging from 12 to 35 years of coverage, depending on the particular type of roofing system installed, how it is installed, and by whom. The Diamond Pledge NDL Roof Guarantee offers strong protection for commercial roofs—and for certain eligible systems, the coverage period can be extended by contracting with a GAF certified contractor* to provide maintenance throughout the roof's life. Additional requirements apply, see gaf.com for details.With proper maintenance, the right roofing system can provide protection for years to come.*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 have agreed that they will use GAF roofing products, and may receive benefits, such as loyalty rewards points and discounts on marketing tools from GAF for participating in the program

Construction planning through to completion can be tricky to coordinate, especially within an urban area, which can present a range of complications. Building proximity, tall building heights, complex building structures, and densely populated areas are just a few challenges that can make it particularly difficult to consider traditionally heavy or large-sized materials when roofing or re-roofing a building.In addition to construction planning constraints, states such as California, New York, and others are adopting more stringent building codes to help alleviate the effect of urban heat islands.As property owners, architects, specifiers, and contractors are seeking new solutions to overcome these issues, the roofing materials industry is seeing increasing adoption of coatings and liquid membrane products that are easy to deliver and apply to the roof, while generating potential labor and installation savings during construction plus lower material costs for long-term maintenance.Benefits of Coatings for Urban ProjectsCoatings offer a distinct advantage in urban construction environments due in part to their mobility, ease of application, and potentially low environmental impact. At an average weight of 60 lbs. (27.2 kg) per 5-gallon (18.9 L) pail that can be carried by a handle, coatings solutions can ease transportation in ways that traditional roofing materials may not. Thanks to service elevators, coatings' advantages are often seen in busy metropolitan areas where using a crane or halting traffic may be expensive or otherwise challenging.Coatings also adhere to many existing roof materials, which can be helpful when restoring a structurally sound, low-slope roof that may have multiple surfaces, such as an asphaltic roof, a metal drip edge, and polyvinyl chloride (PVC) vent pipes.Coatings are manufactured to be "built on site," whether as just a coating with no reinforcement or through a layered approach, where fabric is embedded in the coating to create a reinforced liquid-applied membrane.The versatile application methods of liquid products and fabric rolls are a key benefit to urban construction projects. Many times, these products can be quickly and easily applied using brushes, rollers, or squeegees. These tools are relatively lightweight and easy to transport, and they don't require power or specialized equipment that may not travel well or can be disruptive to residents and neighbors — making them ideal for city construction in tight, crowded spaces.Additionally, with the build-on-site capability of liquid membranes and a lightweight fabric, it's possible to optimize a roof system to match any space. Liquid-applied products can seamlessly adhere to angles, making them an ideal solution for a roof with many details that need to be flashed or angles where a custom fit is needed, conforming to any detail to provide waterproofing protection.Coatings are also useful in maintaining and repairing roofs, which makes them a viable option for building owners and facility managers looking for a roof that can be easily maintained with similar materials to ensure proper adhesion and extend performance.Liquid-applied products can also meet the requirements of a more sustainable and environmentally conscious roofing solution. They may have the ability to restore a structurally sound roof without the need to tear off the existing roof. Additionally, many coatings are manufactured to comply with regulatory requirements, such as low volatile organic compounds (VOC) content, low or no biocides, or being zinc free (always make sure to check local building codes for applicable requirements).Types of Coatings for Urban ProjectsThere are many different technologies when it comes to roof coatings, and each has a unique advantage and offers a unique solution, depending on the needs of a project.Items to consider when selecting a coatings technology often include regulatory requirements and local VOC restrictions, weather conditions affecting the roof, the amount of foot traffic on the roof, and a range of other factors that may be unique to the roof.As with any project, it is important to ensure that each product meets or exceeds testing and certification requirements when selecting any coatings solutions, including the following:• Acrylic coatings are water-borne, typically have low VOCs and low odor, and can easily be applied or recoated in the future. Most acrylics are one-part products, meaning they are ready to use, and there is no need for mixing multiple components. Typically applied via brush, roller, or sprayer, acrylic coatings also offer easy cleanup.• Fluoropolymer (polyvinylidene difluoride, or PVDF) technology is a water-borne technology manufactured using Kynar Aquatec resin, which is based on Kynar 500 technology. The technology provides color stability, a strong solar reflectivity of lighter color coatings, and architectural or aesthetic value. This product is typically used only as a topcoat (over an acrylic basecoat) and on roofs where aesthetics are a primary concern.• Silicone coatings are moisture cured, have low odor, and can be applied easily. Offering a wide range of solutions to many roofs, silicone coatings are generally chosen for their high solids content. In particular, customers choose high-solids silicone coatings because they are suitable for roofs that pond water.• Urethane coatings, both single-component (1K) and two-component (2K), are solvent-borne, high-solids technologies that provide an excellent balance of tensile strength, elongation, and hardness. The 2K urethane products are specifically chosen when durability, dirt and mildew resistance, chemical resistance, weatherproofing, and high abrasion and impact resistance are needed.Combating Urban Heat IslandsThe urban heat island effect can best be described as what happens to urban areas as populations move into a central area — more pavement, fewer trees, more infrastructure, and more hardscape. There are many studies on the effects of urban heat islands, and while hard surfaces such as pavement play a large role, so do roof surfaces. This dynamic leads to higher temperatures in these areas, whereas their surrounding rural landscapes, which often have less pavement, more trees, and less infrastructure, typically see lower temperatures.To help mitigate this effect, coating roofs (and pavement) with lighter, more reflective colors will help lower roof temperatures.By coating an asphaltic roof with a white acrylic coating, one can greatly reduce the surface temperature. According to a 2010 article entitled, "Potential Benefits of Cool Roofs on Commercial Buildings," that reduction may be as much as 55 °F (30.6 °C) and may also result in significant savings in cooling energy. Cooling of the roof not only benefits the building owner but can also reduce the heat island effect in the area.ConclusionsWhether your need is easy delivery to an urban roof project, a creative roof design that will protect the building and provide a seamless detail, or a reflective roof solution to mitigate urban heat island effects, coatings and liquid membranes are a viable solution for you. With many different coatings technologies and manufacturers on the market, the decision can be challenging. To assist with your decision, ensure that you partner with a manufacturer who offers many solutions so you can find the one that is best suited for your project.To explore liquid-applied coatings solutions offered by GAF, click here.