Fire Resistant Flat Roof

The fire rating of a roof covering is either class a class b class c or unrated.

Fire resistant flat roof.

These materials include clay concrete shingles metal roofing and fiberglass asphalt composition. Common underlying materials include a type 72 roll roofing material also known as 72 pound felt or 72 pound capsheet material and a panelized gypsum product called densdeck. The roof sheathing material plays a large role in preventing ignition and slowing the spread of fire to other parts of the building. A one hour rating would mean the structural elements have not yet reached their yield point when exposed to a under deck heat load defined in astm e119 for steel structural members as reaching 1 070 degrees f.

Classes b and c denote progressively less fire resistant qualities. The different materials can vary from zinc copper steel galvanized steel aluminum and so on. The benefit of metal tiles is that they are non corrosive and sit strong on houses with a steep slope. A rooftop fire can result in ignition of the underlying combustible roof deck if the mass of surfacing membrane and insulation is inadequate to thermally protect the deck from reaching its ignition temperature.

A fire resistant or fireproof roof gives the entire structure a better chance to survive a fire. Metal tiles are made of a material that does not ignite when on fire with a fire resistant barrier with a class a protection. Class a roofing materials are the most fire resistant. An unrated roof is the most vulnerable the most common example of an unrated roof covering is one made using non fire retardant treated wood shakes or shingles.

But by including a particular underlying material it can meet the requirements for a class a roof. Class b materials are fire resistant but only withstand moderate exposure to fire. A fire resistant roof includes the entire roofing system including the deck insulation underlayment and even the roof incline. An exterior fire retardant treated shake roof has a stand alone class b rating.

Class a is the most fire resistant and should be the choice of anyone living in wildfire prone areas. Have a look at ecostar s recycled rubber majestic slate traditional tiles. Class b materials are banned in some areas however because they are combustible. Expect to pay between 6 50 and 8 50 per square foot installed.

Fire resistance ratings time temperature include structural elements and everything above including the roof membrane and its surfacing. Metal is an extremely fire resistant roofing material regardless of what material the shingles are composed of. Shingles are categorized into classes that identify their fire resistance. Manufactured using a highly effective fire retardant and underlaid with a fire resistant barrier this assembly is one of only a few synthetic roofing materials to get ul s class a fire rating.

When tested to see how fast a fire spreads with these materials class a materials stop the spread two feet better than class b. Most metal roofs are made of steel copper zinc and alloys that are best for the dry environment in nevada.