Metal Roofing: Questions and Concerns
Lightning strikes on metal roofing are a question and a concern that comes up regularly as we work with homeowner’s considering an upgrade to Stone Coated Metal Roofing.
The bottom line is that metal roofing is no more likely to attract lightning than any other type of standard roofing materials. In fact, stone coated metal roofing is the most desirable roofing system to protect your homes and commercial properties throughout Montana and Wyoming. Most Wyoming and Montana metal roofers or roofing contractors recognize that metal is a non- combustible material, meaning that a lightning strike will not turn into a roof fire. At Billings Metal Roofing all of our metal roofing systems carry the highest Class A fire resistance rating.
When lightning strikes your roof it will channel through the property on its way to the ground thru your property’s plumbing pipes and electrical wiring systems and it won’t matter if your roofing material conducts electricity or not. Wood Shakes and Asphalt Shingles are extremely combustible or flammable and are easily ignited.
Fire is probably one of the most dangerous hazards of a lightning strike to your roof. Asphalt shingles and wood shakes are easily ignited and will jump from the roof into the attic and then into the wall systems as it makes its way to the ground. Last year, fire departments answered 22,600 calls where fires were started by lightning. Stone Coated Metal Roofing is best in its class with Class A fire resistant, non-combustible investment grade steel. Metal roofing will also spread out the electrical surge eliminating an explosive surge reducing the possibility of power surge damage inside your home or business. Check out our comparison charts here.
Shock Wave Damage due to Lightning
A sudden explosion of thunder is the classic signature of lightning and the shock wave that follows it. These shock waves can shatter typical building products and send fractured material and shrapnel. It is common to find these daggers imbedded in walls, trees, and other structures after a strike. A metal roofing system will add the strength and durability of steel to your roof system, withstanding the force of lightning shock waves, high winds and 2 1/2” hail that often come along with typical Wyoming and Montana thunder storms.
Billings Metal Roofing for a Lifetime
All or our metal roofing systems stand up to whatever weather events Mother Nature presents us with: high winds, two inch hail stones, lightning strikes and such. Our warranties are the strongest in the metal roofing industry, are never pro-rated and are fully transferable to a new home or business owner. Insurance underwriters love the strength, durability, and longevity of stone coated metal roofing systems and will oftentimes offer discounts up to 25% along with lower deductibles for property insurance policies.
Take a quick look at our roofing systems comparison charts and out gallery of lifetime metal roofing installations. With unsurpassed strength, lifetime durability, significant energy savings, Federal Property Tax Credits, increased equity, and low interest home improvement loans there has never been a better time to invest in quality stone coated metal roofing from Montana Metal Roofers, Metal Mart and Billings Metal Roofing.
Oftentimes, if you live in Wyoming or Montana, and you are looking for siding and roofing materials to help your home survive a wildfire you will want to remember the terms Wildland Urban Interface or (WUI), noncombustible, non-flammable, ignition resistant, Class A rated and fire-resistant. These are terms that describe the relative combustibility of different siding and roofing materials. Sometimes siding and roofing contractors refer to the material that you are considering for your home like seamless steel sidings or metal roofing systems (fire-resistant), and other times they refer to building techniques (ignition-resistant).
Now, the first thing that needs to be addressed here is, are all noncombustible, non-flammable, ignition resistant, and fire-resistant materials and building techniques considered “good”? While combustible materials are considered “bad.” Siding and Roofing Contractors along with remodeling contractors and general contractors will stress the value associated with using noncombustible, non-flammable, ignition resistant, Class A rated materials in your remodeling projects and they basically just leave out trying to rate the different combustible materials and their performance.
At Billings Metal Roofing, along with our partners at abc Metal Mart and Montana Metal Roofers we will not be discussing the pros, cons, or performance of combustible materials. We do not believe in using them, and will not get into the various ways that these substandard materials are rated.
Let us look at the ways building codes and test standards have defined the terms used to describe how different sidings and roofing withstand fire.
Fire-resistant or fire-resistance
The terms combustible and noncombustible refer to different materials used in remodeling, new construction and storm restoration. For example with seamless steel siding, the siding itself is noncombustible while the insulation and sheathing behind it may not be. As a building technique this entire model is considered ignition resistant, and both scenarios may include a Class A fire rating.
How the two terms are used?
Combustible materials ignite and burn. Most people consider wood products combustible. An important thing to consider here is the wood-plastic composites, manufactured wood, and plastic products like vinyl sidings and decking are also considered combustible and many times it is the smoke or exhaust that is deadlier than the fire itself. Living in Wyoming and Montana, with regards to wildfire we want to consider two different properties – flame spread index and heat release rate. This is all measured with what is called a Steiner Tunnel and the results can be found on our comparison charts.
A noncombustible material is not capable of combustion under specified conditions.
This is were it gets interesting. Ignition resistant in not fully defined in most parts of North America and therefore it can mean different things to different people. The Wildland-Urban Interface Code has defined ignition resistant materials as those meeting a minimum flame spread rating after being subjected to a specified wetting drying weathering cycle. The testing is basically a 30 minute test were the material is subject to certain temperatures at different lengths of time. The Material must withstand ignition for 30 minutes to be considered ignition-resistant. Wood and Manufactured wood products are usually treated with a fire retardant. This retardant us usually easily bleached from the product by weather. Fire resistance ratings provide guidance on material’s ability to contain a fire and still maintain structural function providing time before the building collapses. Rating go from 20 minutes to several hours.
Test used to determine the fire ratings for roofing start at Class A the highest degree of fire resistance, followed by B or C ratings. The standard roofing test will also evaluate flame spread over the material and the materials ability to generate embers. This is why metal roofing systems typically show higher Class A ratings.
Differences in fire performance for different siding and roofing systems are evaluated as Class A (best) Class B (better) Class C (good) Noncombustible Steel Sidings and Roofing Systems are either defined to the roofing contractor in the building codes or they have met requirements on a standard test.
Ignition resistant materials are still combustible and typically are rated by withstanding a 30 minute flame spread test.
Given the use of these terms, you can rank the expected performance of construction materials as follows:
Noncombustible – Best performance for both flame spread and penetration.
Fire resistance – Fire Resistant construction – Materials with this classification can be expected to perform better than combustible materials but not as well as noncombustible.
Combustible – Materials with this classification will not perform as well as the others discussed in this article, given a comparable fire exposure.
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