Are Metal Roofs Fire Resistant? Evaluating their Strength against Flames
Let’s face it: when you live in a state like Montana, you need to be prepared for just about anything, especially during wildfire season. From May through October, the Big Sky State often faces flames, wildfires sprouting up from Custer Gallatin National Forest to Glacier National Park. According to a study by the Insurance Information Institute, Montana has the highest percentage of properties at risk of wildfire damage at 29%.
Naturally, homeowners impacted by wildfires want to take precautions to protect their loved ones and property from wildfire damage. This includes their housing materials. When choosing roofing materials, fire resistance is one of the top factors to consider—that’s why we recommend metal roofing.
Over the years, metal roofing has become one of the most sturdy, reliable, and energy-efficient options available. In Montana, residents choose metal roofing so their buildings can be better protected against any harsh elements. But what about wildfires? Are metal roofs fire-resistant?
Below, we’ll explore the qualities of metal roofing and how its naturally durable structure can be a benefit during wildfire season.
Answering the Question: Are Metal Roofs Fire-Resistant?
Metal Roofs: Fireproof vs. Fire Resistance
When answering the question “Are metal roofs fire-resistant?”, we first need to examine the word “fire-resistant.” Fireproof and fire resistance are often used interchangeably, but they are not the same —especially with metal roofing.
Let’s begin with the word “fireproof.” In reality, not much is actually fireproof. Anything can get hot enough to get destroyed when a wildfire rages across the countryside—including metal roofs. A metal roof can’t provide 100% foolproof fire protection. A truly fireproof material would not catch on fire or contribute to the spread of flames, and it’s rare to find a material that can make that bold of a claim.
That’s why we prefer the label “fire-resistant” with metal roofing. Fire resistance refers to a material’s ability to withstand fire for a set period of time without contributing to the spread of flames or without losing its structural integrity. So while metal roofs have excellent, verified fire-resistant properties, they are not completely immune to fire damage. They do, however, perform better than shingles or cedar planks when facing the flames. This makes a metal roof the best roof for wildfire resistance.
There are different class systems that define how fire resistant a roofing material is, labeled as Class A, B, C, or unrated. Class A is the best rating a roofing material can receive for fire resistance. To its credit, most metal roofing products are considered Class A rated. However, this is often limited to just the product as it is, also known as the “stand-alone” fire rating. For the whole metal roof to be considered Class A rated, the entire roofing system would need to be compliant for fire resistance, including the roof’s underlying materials. This is called the “by assembly fire rating.”
Mitigate Risk of Wildfire Damage: Why Choose Metal Roofing
While metal roofs are not “fireproof,” their fire resistance is a huge asset to your property. Just like adding sprinklers to a building or smoke detectors, upgrading your building with fire-resistant roofing materials—like metal roofing—is an investment in safety and property protection.
Most metal roofing materials are intrinsically fire resistant. Steel is the most popular choice for fire-resistant metal roofing, as it has a high melting point. Aluminum, as well, has a low ignition point and does not contribute to the spread of flames. Copper has a high melting point, as well, and does not burn or release any toxic fumes when exposed to fire. While it has a relatively low melting point, Zinc can withstand high temperatures without compromising its structural integrity.
Overall, the inherent properties of metal roofing materials help contribute to its fire resistance, lending a hand in defending your home or commercial building. Here are a few of the characteristics of metal roofs that contribute to their fire-resistant natures:
- Noncombustible – Metal is a non-combustible material, meaning it does not burn when exposed to fire. Unlike flammable materials such as wood or asphalt, metal roofing does not contribute to the spread of flames.
- Heat Reflectivity – Metal roofing materials have high reflectivity, meaning they can reflect a significant amount of the sun’s heat away from the building. This property helps in reducing heat absorption, minimizing the risk of fire caused by heat buildup.
- High Melting Point – As previously mentioned, metals used in roofing—such as steel, aluminum, copper, and zinc—have high melting points. This means they can withstand high temperatures before reaching their melting point, providing increased resistance to fire.
- Limited Combustible Fuel – Since metal roofing panels do not have combustible components, such as oils or organic materials that can contribute to the spread of flames, they do not provide fuel for fire.
- Resistance to Ember Attacks – Metal roofs are less susceptible to ember attacks, which are common during wildfires. The smooth surface of metal roofing helps prevent embers from entering the structure, reducing the risk of ignition.
- Structural Integrity – Metal roofing does not easily collapse or fail when exposed to fire, allowing the roof to provide protection to the building and its occupants during a fire event.
Additional Benefits of Metal Roofing and Siding
Along with its fire-resistant properties, metal roofing (and siding, for that matter) provides extra benefits for your building, adding long-lasting value to your property.
- Longevity – Metal roofs are incredibly strong, so they need to be replaced far less frequently than asphalt roofs. Metal roofs will carry a manufacturer’s warranty of roughly 30-50 years and last much, much longer, often up to 70 years.
- Durability – Thanks to the material’s inherent sturdiness, metal panels are able to withstand the test of time without corroding or cracking. Additionally, rust-proof coatings and protection add to the roof’s ability to withstand wear and tear.
- Weather Resistance – Metal roofs are able to withstand intense weather conditions in a way that asphalt and other roof options cannot. Whether it’s strong winds, hail, ice storms, or snow, metal roofs keep their structural integrity during all of these conditions.
- Aesthetics – Since metal panels can be painted and repainted, you can choose the metal roof color that matches the style of your building. There are a lot of metal panel color options to choose from along with panel style, concealed fasteners versus exposed fasteners, and texture.
- Noise Reduction – Despite the common misconception, metal roofs are not loud and can even be quieter than shingles. They’re excellent at protecting your home from noise pollution, and you can add insulation boards and upgrades to dampen any noise that comes with heavy rain or hail.
Wildfire Resistant Roofing: Metal Panels vs. Other Roofing Materials
There’s really no competition when comparing the fire resistance of metal panels versus. other roofing materials. Look at it this way: if an ember lands on a steel roof versus a cedar or asphalt roof, it is less likely to catch your structure on fire. Here are a few reasons why roofing materials like asphalt, thatch, and wood shingles don’t hold a candle to metal roof panels:
- Combustible Nature – Roofing materials like wood shingles, asphalt shingles, or thatch can ignite and burn when exposed to flames or high temperatures. Their combustible nature increases the risk of fire propagation and can contribute to the spread of flames.
- Lower Melting Points – Non-metallic roofing materials generally have lower melting points compared to metal. For instance, asphalt shingles can soften and melt at relatively low temperatures, leaving the underlying structure vulnerable to fire damage.
- Fuel Source – Roofing materials that contain organic components, like wood or thatch, can serve as fuel for fire, sustaining flames and further endangering your property.
- Structural Integrity – When exposed to fire, non-metallic roofing materials are less sturdy than metallic ones, easily weakening, deforming, and collapsing.
Keeping Your Structure Fire Resistant
Installing metal roofing on your property plays a major part in protecting your home from wildfire damage, but there are other precautionary measures you can take to ensure your structure is fire-resistant.
- Clear Vegetation Near the Roof – Trim any trees or shrubs near your roof, as overhanging vegetation can serve as fuel sources and increase the risk of fire damage.
- Remove Debris from Your Roof – Regularly clean your roof and keep it clear of leaves, branches, and other flammable materials.
Have Your Roof Routinely Maintained – Regularly inspect your roof for signs of damage and have it repaired as soon as possible.
Invest in Fire-Resistant Roofing Materials, Install Metal Panels
If you have specific questions about metal roofing’s fire resistance or how to best protect your next residential or commercial metal roofing project, we’re here to help. At Great Northern Metal Company, our Bozeman metal roofing experts can make expert recommendations to ensure you have all the information you need to better protect your structure from fires. Get a quote today or give us a call at (406) 624-0435—we’d be happy to answer any questions!
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
