Commercial roofing plays an important role in maintaining the performance and longevity of your building while also keeping the occupants and assets within protected from the elements. According to the ICCPC, or ICC Performance Code for Buildings and Facilities, building performance has been defined as “the structure’s capacity to withstand specific magnitudes of events within a tolerable limit of damage”. The “events” referred to here can include natural, expected hazards, or technological hazards.

Natural Hazards — can include ice, snow, wind, rain, frost, thermal loads, etc.

Technological Hazards — can include fires and explosions as well as exposure to toxic or corrosive materials.

Roof damage is typically caused by one or more of the following factors:

• Flaws in the roof design
• Poor quality materials
• Unskilled or inexperienced installation work
• Material deterioration
• Inadequate roofing application

Properly designed and well-maintained roofs can provide adequate fire safety and proper wind load resistance to protect the building and occupants within from roof failure.

Fire Ratings and Fire Resistance

Designing a roof that will resist the penetration and spread of fire is easier than designing one that will not cause these problems.

Fire safety is an important concern for any commercial roof building, not only to protect the value of the structure but more importantly to save the lives of the occupants within. The commercial roof must be installed with certain safeguards that will stop the spread of fire and thereby minimize the loss of property, building damage, or severe injuries or fatalities due to toxic fumes, fire, and smoke.

To improve and encourage fire safety in commercial buildings, certain fire ratings have been laid out. These fire ratings provide roofing materials with a rating indicating their performance in case of fire. Class “A” is the highest possible fire rating and provides the best performance in fire safety. Class “C” and underrated are the lowest grades and provide minimal protection.

Important considerations for fire-resistant commercial roofing — System type and slope

Noncombustible roofing materials, like concrete and clay tiles, slate, asphalt-glass composition shingles, and metal panels, all receive a very high fire safety rating, typically A or B. But it is important to remember that the rating provided for your roof will be the sum of all its parts. As mentioned in the NRCA tech article, even if some roofing materials are Class A, the roof decks and underlayment sheets selected for use in this roofing system may not qualify for Class A or B ratings.

Alterations in the 2009 International Building Codes, or IBC, now make it mandatory that all buildings and roofs are regularly subjected to a standard fire test that will determine their expected performance when exposed to fire. The only exception is those roof coverings installed over noncombustible roof decks or framing. Wood shakes and roof coverings made of noncombustible rubber or aluminum need extra materials to be used with the roof covering and sheathing that will make the roof eligible for a Class A rating.

Another key point on the topic of fire-rated roof coverings is that when they are used on steep slopes their fire resistance is impaired. In this situation, roofing contractors must take additional measures to ensure that the roof structure’s fire-resistant properties are improved.

Wind Uplift Ratings and Wind Load Resistance

Many different factors can affect the way a building is affected by the wind. This can include the height of the building as well as its exposure to high-speed winds. For example, buildings that are in urban and suburban areas typically enjoy protection from strong winds. On the other hand, those buildings located near large expanses of featureless terrain or open expanses of water can experience very strong winds and this can increase wind loads.

Wind uplift happens when the air pressure above the roof drops below the air pressure below the roof. A variety of wind uplift ratings are used to test the resistance of a roof’s structures to uplift. Uplift is always the strongest at the roof’s corners and edges. This can be one of the most catastrophic effects of strong winds that can devastate buildings and cause roof blow-offs, damaged roof covers, and roof structure collapse.

Roofing contractors must pay close attention to the commercial roof they will be putting in place to mitigate uplift and reduce the damage caused by wind force. Correctly attaching the roof system to the building involves choosing the proper wind-life complaint roofing materials which are critical to minimizing wind resistance.

Another example would be the fasteners that are applied at the perimeter and corners of the roof to hold membranes in place. These must be chosen to meet the specifications for roof uplift loads. For commercial buildings in locations where the wind speeds will typically increase beyond 90mph, certain design, maintenance, and construction enhancements are also a good idea.

Wind and Fire Safety Concerns

If you are not sure about the safety specifications, codes, and other guidelines that apply to your location, this can all be rather confusing. Contact your local roofing contractor for more information.

Armadillo Roofing & Exteriors (512) 333-7663, provides commercial roof repair, commercial roof installation and commercial roof replacement services to Austin, Texas and the surrounding communities and has been providing commercial roofing services to the area for over 19 years. When you need advice to protect your commercial roof from wind and fire issues, give us a call. Also, if you have a metal commercial roof, check out our other website at ArmadilloMetalRoofing.com.