The Role of Light and Dark Metal Roofing and Siding Colors in Energy Efficiency
You have many options to choose from when selecting metal roofing and siding colors for your project. Picking a color that compliments your project’s aesthetic and matches your personal preferences is one of the most fun parts of a project, but choosing a metal panel color goes beyond selecting your favorite shade. Your choice of metal roofing and siding colors can also impact the energy efficiency of your project. Darker metal roofing and siding colors—like charcoal gray or matte black—absorb more solar heat because they have a low Solar Reflectance Index. On the other end of the spectrum, lighter colors have a high Solar Reflectance Index because they reflect more solar heat than they absorb. Both sides of the Solar Reflectance Index can affect a building’s overall energy efficiency. Does this mean you should choose something other than dark materials for your metal roofing and siding project? Absolutely not! While the science of color dictates heat absorption or reflectance, metal roofing and siding systems are among the most energy-efficient roofing solutions, from installation to paint. Read on to learn more about the Solar Reflectance Index, its impact on your roof’s efficiency, and the overall benefits of metal roofing systems for energy efficiency.
How Does Color Impact a Metal Roof’s Energy Efficiency?
Metal roofing is recognized as one of the most energy-efficient roofing methods. However, it is not just the materials of a metal roof that make it so; the colors of the metal panels also impact a roof’s energy efficiency. Depending on the Solar Reflectance Index, a roofing color can be more or less energy efficient.
Understanding the Solar Reflectance Index
The Cool Roof Rating Council explains that the Solar Reflectance Index (SRI) “is an indicator of the ability of a roof’s surface to return solar energy to the atmosphere.” This means that when solar energy heats the roof of a home, a portion of that solar energy is either reflected back into the atmosphere by the roof’s surface or absorbed. The solar energy that is absorbed by a roof is then transferred inside the home. Whether solar energy is reflected back or absorbed into a home determines how high or low a roof’s SRI value will be. Solar Reflectance Index values range between 0 and 100 and are determined by a roof’s ability to radiate heat and the energy that it reflects back. Roofs with low SRIs, such as those with black or dark tones, have warmer surface temperatures. In comparison, roofs with higher SRIs in lighter colors, like white or silver, have cooler surfaces. When choosing a color for your project, a low or high SRI roofing material can affect a home’s comfort and energy efficiency, especially in inclement climates.
SRI’s Impact on a Metal Roof’s Energy Efficiency
Low SRIs In frigid climates like those in Montana, choosing dark-toned materials with lower SRIs can help contribute to passive home heating during winter months. When winter sunlight heats a darker-colored roof, the solar energy is then transferred inside the home. Remember that those same dark roofs can continue to warm a home in the summer, too. If a house becomes too warm in the summer, the air conditioning system can run longer to cool the interior. High SRIs Lighter-colored metal roofing and siding materials have a higher SRI and are good at reflecting solar radiation. These lighter hues help minimize heat buildup. For example, white residential metal siding does not absorb solar energy the way a home with a dark roof and siding would. Instead, it reflects up to 90% of sunlight heat. When a home’s exterior reflects heat, its cooling systems often do not have to run as long to cool the interior.
Considering SRI When Choosing a Metal Panel Color
- Stone White: Bright whites have a high SRI, meaning they reflect much of the sun’s heat. White-colored metal panels can also lend to a clean, light aesthetic for your home.
- Patina Green & Slate Blue: Hues of greens and blue contribute to a natural, calm feel for buildings. These colors tend to reflect more light, which makes them energy efficient.
- Dark Bronze: Shades of bronze have a classic, earthy feel—perfect for Montana. Darker bronze tones with a moderately low SRI absorb more energy than light tones.
- Charcoal Gray: This subtle color often symbolizes elegance and sleekness. Deep gray tones can have a lower SRI value, which means they absorb more energy than reflect it.
- Matte Black: Black tones absorb the most energy and, therefore, tend to have a low SRI value. This popular tone has a contemporary feel and can add a dramatic flair to any building.
Should SRI Impact Your Roofing & Siding Decisions?
While SRI does play a part in a roof’s energy efficiency, don’t worry about the details if you are tying yourself in knots deciding between a light or dark color. Yes, SRI can impact efficiency, but it is minimal when considering the overall energy-efficient nature of metal roofs and the fact that many paints used for metal panels are Energy Star rated. Understanding this can be helpful to your color decision-making process, especially if you want a dark-colored roof but worry about SRI. You can choose darker tones and have your structure be energy efficient, too! Learn more about the energy-efficient nature of metal panels and Energy Star-rated paints below.
The Energy Efficiency of Metal Roofing and Siding: Installation, Paint & More
As we mentioned before, metal roofing and siding panels are highly energy efficient from installation to the material of the panels themselves. The installation method for attaching metal roofing—a batten/counter-batten system—creates air gaps that insulate and stop heat from escaping. Because of this natural insulation, a home’s interior temperature is regulated more effectively, which reduces the need for the HVAC system to work overtime. Also, metal roofing and siding are more efficient when compared to traditional asphalt shingle roofs. Asphalt shingle roofs take hundreds of gallons of oil to install. This makes installing shingle roofs wasteful and hazardous for the environment and humans. Further, if traditional shingle roofing materials are not coated with reflective granules, the shingles can become extremely hot. When they get warm, asphalt shingles transfer heat back into a home, causing the cooling system to work overtime cooling your interior. Energy savings are lost, and utility bills increase. Comparatively, because of its low thermal mass, metal roofing and siding do not transfer heat in this same manner—making it a better energy-efficient choice. Bonus: many metal roofing and siding paint colors are typically Energy Star rated to reflect UV and infrared light rays. This helps buildings and homes save on energy costs all year round, no matter what the color of the panel is. When selecting a metal panel color, double check to see if the paint is Energy Star rated.
Need Help Choosing Metal Roofing & Siding Colors?
A lot of thought goes into the decision-making process when choosing metal roofing and siding colors for a commercial metal roofing or residential metal roofing project. Not only is the color aesthetic important, but so is a structure’s energy efficiency. At Great Northern Metal Company, we are experts in helping contractors and homeowners choose the best energy-efficient colors for projects. We’re here to ensure your vision is built with the highest quality materials and services. Reach out to our Bozeman metal roofing professionals for a quote today, message us, or call us at (406) 624-0435.
What Is Sealant for Metal Roofing?
Metal roof sealant helps seal seams, joints, gaps, and other areas where water or air could enter a roofing system. Most gun-grade sealants are applied from a tube and form a bead over or within a joint. Depending on the formulation, the material may remain permanently pliable or cure into a flexible seal.
For metal roofing, flexibility matters. Panels naturally move as temperatures rise and fall, so a sealant used at a moving joint needs to accommodate that movement without losing adhesion.
The location of the seal matters too. A product used at an exposed seam may need different properties than one placed inside a concealed joint.
Sealant also should not be treated as a substitute for proper flashing, fastening, or panel installation. It works as part of the roofing system, not as a fix for a detail that was built incorrectly.
What Is Butyl Tape for Metal Roofing?
Butyl tape is a preformed sealing material typically installed between two roofing components. Instead of applying a bead from a tube, the installer lays a continuous strip of tape along the joint before the materials are fastened together. That makes it especially useful at concealed laps and other locations where two metal surfaces come together.
Butyl stays flexible, which helps it maintain a seal as a metal building experiences normal movement. There are also expanding sealant tapes that serve a similar purpose while filling irregular gaps and accommodating movement within the joint.
Sealant vs. Butyl Tape
The simplest way to think about the difference is application.
Gun-grade sealant works well when you need to apply a bead into a seam, joint, or gap. Butyl tape works well when you need a continuous seal between overlapping or adjoining components.
One is not automatically better than the other. The roof detail determines which type makes sense.
Metal Roof Sealant vs. Butyl Tape: Which Should You Use?
Different roof details put different demands on the sealing product.
These are general guidelines. Always check the roofing-system requirements and the manufacturer’s installation instructions before choosing a product.
4 of the Top Metal Roof Sealants and Butyl Tapes
The right product depends on the joint, expected movement, temperature conditions, and whether the seal will be exposed or concealed.
Here are four options GNMC has tried, tested, and trusts so much that we chose to carry them at our shop.
Best for: Expansion joints, lap seams, and joints that need to accommodate movement.
EMSEAL AST Hi-Acrylic Sealant Tape is a self-adhering, open-cell polyurethane foam tape impregnated with acrylic-modified asphalt.
Unlike a standard flat tape, EMSEAL AST gradually expands after it is removed from its packaging. That allows it to conform to the joint and fill gaps along irregular surfaces. For metal roofing and metal buildings, that can be particularly useful around details affected by thermal expansion and contraction.
Why It Works Well With Metal Roofing
One of EMSEAL AST’s biggest advantages is its ability to move with the building. The tape conforms to contours and maintains a seal as metal panels expand and contract. It is designed to help keep out dust, air, wind-driven snow, and moisture through joint details.
It also does not dry out and become hard or brittle over time. Because the material remains compressed within the joint, it is designed to stay in place rather than squeeze out the way some caulks or butyl products can.
Its resistance to UV exposure, aging, and mildew also makes it well suited to demanding exterior applications.
Common Applications
EMSEAL AST can be useful for:
- Expansion and compression joints
- Lap seams
- Mechanically fastened joints
- Irregular gaps
- Metal building details where movement needs to be accommodated
It can also be used alongside several common building materials, including metal, plastic, wood, and concrete.
Interested in EMSEAL AST? Contact GNMC
Best for: Metal panel joints that need a permanently pliable, gun-grade sealant.
TFC BUTYL™ is a single-component butyl-based sealant designed specifically for strong adhesion to metal panels.
Its biggest distinction is that it remains permanently pliable. It does not skin over into a hard surface, which allows the material to continue moving with the joint after installation.
Why It Works Well With Metal Roofing
Metal panels do not stay perfectly still over the life of a building. Temperature changes create movement, and joints need a sealing product that can handle it.
TFC BUTYL remains flexible and moisture-resistant, which makes it useful for metal panel details where a rigid sealant would not be appropriate.
It also meets or exceeds AAMA 809.2 and is available in gray or white.
Installation Matters
Good adhesion starts with a clean surface. Before applying TFC BUTYL, the substrate should be dry and free from frost, oil, grease, incompatible coatings, or other contaminants that could interfere with adhesion.
The product is applied using a standard caulking gun and can be tooled after application if needed.
It is also worth paying attention to storage. TFC BUTYL should be kept in a controlled, dry environment below 75°F and used within 12 months of manufacture.
One other detail to know before choosing it: TFC BUTYL is not paintable.
Ask GNMC about TFC BUTYL™.
Best for: Seams, panel joints, and gaps that need a flexible cured sealant.
NovaFlex Metal Roof & Panel Adhesive Sealant is a single-component silicone sealant and adhesive commonly used as a seam sealant or joint filler in metal roofing and panel systems.
It is non-corrosive and non-sag, making it useful where contractors need a gun-grade product that will stay where it is placed.
Why It Works Well With Metal Roofing
Temperature range is one of NovaFlex’s standout characteristics. The product can be applied at temperatures from -20°F to 160°F and has a service temperature range of -40°F to 400°F.
That broad range is useful for metal roofing, where surfaces can experience substantial temperature swings.
NovaFlex also offers good adhesion to common building materials and can bridge gaps up to 3/8 inch. Its exterior weathering and aging performance make it suited to exposed building applications.
Where NovaFlex Makes Sense
Contractors may consider NovaFlex for:
- Metal roof seams
- Panel joints
- Joint filling
- Small gaps
- Details exposed to wide temperature swings
It remains flexible at temperatures down to -10°F and is freeze-thaw stable. There are a couple of limitations worth knowing before installation. NovaFlex is not recommended for joints that will be submerged underwater, and it should not be used on surfaces that will later be painted.
Cure time also depends on temperature and humidity, so installers should account for site conditions and follow the product instructions.
Contact GNMC about product availability.
Best for: Concealed metal building joints that need a continuous, flexible seal.
MB-10A Butyl Tape is an elastomeric butyl rubber sealant specifically designed around the requirements of metal buildings.
It comes extruded on silicone-coated release paper, which makes it straightforward to position during installation. It is also produced in different sizes and lengths to suit a range of applications.
Why It Works Well With Metal Roofing
MB-10A is designed to maintain its seal through normal building movement. Its combination of adhesive strength and cohesive strength helps the tape stay together and stay bonded as the assembly moves.
Temperature performance is another important benefit. MB-10A is designed to withstand extreme roof temperatures while maintaining compressibility in colder conditions. It also offers resistance to UV light and cold flow.
Those characteristics matter on metal buildings, where the material may experience a wide range of temperatures throughout the year.
Common Applications
MB-10A may be a good fit for:
- Concealed panel laps
- Metal building joints
- Overlapping components
- Details requiring a continuous butyl seal
- Joints affected by normal building movement
Choosing the right tape size is important. The joint needs enough material to create the intended seal without using so much that the tape squeezes excessively out of the detail.
Inquire about MB-10A Butyl Tape
What to Consider Before Choosing a Metal Roof Sealant
Before grabbing a tube or roll, look at what the joint actually needs and ask yourself the following questions:
- How Much Will the Joint Move? Metal panels expand and contract as temperatures change. A sealing product at a moving joint needs enough flexibility to accommodate that movement.
- What Temperatures Will the Product See? Metal roof surfaces can get hot, and Montana projects can also see very cold conditions. Check the product’s application temperature separately from its service temperature. A sealant may perform across a wide temperature range once cured while still having specific limits for installation.
- Is the Joint Exposed or Concealed? A concealed panel lap has different needs than an exposed seam. Butyl tape is often a practical choice where two materials are compressed together. A gun-grade sealant may make more sense when a seam or gap needs to be filled from the outside.
- What Materials Is the Product Touching? Always check compatibility with the metal substrate and any adjoining materials. A product that adheres well to bare metal may have different requirements around painted finishes, other coatings, plastics, or masonry.
- Will the Surface Be Painted? Some sealants are not paintable. Both TFC BUTYL and NovaFlex have limitations that should be understood before choosing them for a detail that will receive a finish later.
- What Does Installation Require? Good products still need good installation. Surface preparation, storage, bead size, compression, and cure time can all affect the finished seal. Read the product instructions before installation instead of assuming every sealant or tape works the same way.
Frequently Asked Questions About Metal Roof Sealants and Butyl Tape
What is the best sealant for a metal roof?
The best metal roof sealant depends on where it will be used. Gun-grade sealants can work well for seams and joints, while butyl tape is commonly used between overlapping components or in concealed joints. Movement, temperature, substrate compatibility, and exposure should all factor into the decision.
Is butyl tape good for metal roofing?
Yes. Butyl tape is well suited to many metal roofing details because it creates a continuous seal between components while remaining flexible enough to accommodate normal building movement.
Is sealant or butyl tape better for a metal roof?
Neither option is better for every application. Butyl tape is often used inside laps and concealed joints, while gun-grade sealants are useful for filling seams, joints, and gaps. Some details may use both as part of the roofing system.
Does metal roof sealant need to stay flexible?
For joints that experience movement, flexibility is important. Metal panels expand and contract as temperatures change, so the sealing product needs to accommodate the expected movement without losing adhesion.
Can you use any silicone sealant on a metal roof?
No. Use a sealant that is compatible with the roofing material, coating, joint design, and expected temperatures. The product instructions and roofing-system requirements should guide the choice.
Need Metal Roof Sealant or Butyl Tape for Your Next Project?
Great Northern Metal Company carries EMSEAL AST, TFC BUTYL™, NovaFlex, and MB-10A Butyl Tape for a range of metal roofing and metal building applications.
Tell our team what detail you are working on and what you need the product to do. We can help you review the options GNMC carries and get the right product information before you place an order.
Inquire About Metal Roof Sealants
