COMMITTEE FOR FIRESAFE DWELLINGS

· Stone coated steel roofing installed over wood shake is rated as Class “C”, if specific additional fire resistive materials are not installed in an approved manner.

· To achieve a Class “A” rating over wood shake roofing requires a layer of ½-inch gypsum board. (With some manufacturers it is not possible to have a class “A” installation over wood shakes.)

· The installation weight for Class “A” over shakes, including the steel panels⁽¹⁾, old wood shakes⁽²⁾, wood support system⁽³⁾, and gypsum boards⁽⁵⁾, is 730 pounds per square (a square equals 100 square feet of surface area, in this case that equals 7.3 pounds per square foot). This is heavier than composition and light weight concrete tile roofing.

· The installation weight for Class “C” over shakes, including the steel panels⁽¹⁾, old wood shakes⁽²⁾, and wood support system⁽³⁾, is 560 pounds per square.

· The warranty coverage on the stone surface coating is typically only 20 to 25 years, after which the homeowner has no coverage if the stone coating erodes down to bare metal.

· Warranty coverage is typically prorated, meaning that the homeowner will most likely be paying an ever increasing amount, as time passes, for any repairs, even those covered under the warranty.

· When is a Class “A” roof not Class “A”? Manufacturers of stone coated steel roof products fail to highlight the fact that their Class “A” rating in conditional upon the type of installation. Depending on the way it is installed, it can be either a Class “A,””B,” or “C” system. Achieving Class “A” in re-roof application over wood shakes is, in the case of some manufacturers, not possible or, with others, requires the extra cost and considerable weight of a layer of ½-inch gypsum board. Stone coated steel roof products were “grandfathered” into the building code as Class “A,” however, they have failed standard burning brand tests for a Class “A” rating which were conducted by a certified testing laboratory.

When is a “lightweight” roof not lightweight? Referring to stone coated steel roof panels as “lightweight,” when used in a Class “A” re-roof application over wood shakes, is very misleading. The steel roof panel manufacturers imply that their product, when installed as a Class “C” assembly, over an existing wood shake or shingle roof, weighs 140 to 150 pounds per square. It is very important to recognize that when the weight of the existing

· roof of 350 pounds per square or more and the weight of the wood support system (battens and counterbattens) of approximately 60 pounds per square are taken into account, the actual weight of the combined components is almost four times greater than quoted by the manufacturers.

When these products are installed as a Class “A” assembly, the installation is the same as for a Class “C” assembly, except a layer of ½-inch gypsum board⁽⁵⁾ has to be added at an approximate weight of 170 pounds per square. This brings the combined weight of all the components to 730 pounds per square. 730 pounds per square (7.3 lbs./sq.ft.) is well above the generally accepted maximum weight of 600 pounds per square definition for lightweight roofing. At weights of 600 or more pounds per square, most communities require an engineering evaluation of the roof structure which could lead to the necessity for structural reinforcement. It should also be noted that some steel manufacturers cannot achieve a Class “A” rating on their products that are installed over wood shakes regardless of weight or construction components.

· Is a stone coated steel roof installed over a wood shake or shingle roof fire safe? In the late 1980’s and early 1990’s the fire service experienced many residential fires involving this type of re-roof system which resulted in extensive fire damage and occupant fire safety concerns. In an effort to address these issues the California Fire Chiefs’s Association (CFCA) and the Steel Roof Manufacturers’ Association (SRMA) conducted several fire tests (Building Standards Committee Report 1993-4, FPO/CFCA) at the Weyerhaeuser Laboratory in Longview, Washington, on June 9 and 10,1993. These tests showed that re-roof systems of this type, when installed with a fire black material, 1 ½-inch thick foil faced Manville Microlite fiberglass insulation⁽⁴⁾ installed directly on top of the wood shakes⁽²⁾ (Test No.3), greatly reduced the spread of fire through the re-roof system. The CFCA accepted the test result using this type of fireblocking as a reasonable and prudent method to provide a fire resistive re-roof system. However, this system of insulation has a maximum fire resistive rating of Class “B”.

When considering the purchase of a new roof, be sure to ask the following questions:

· Will the re-roof, if installed over an existing wood shake or shingle roof, include the fireblock material and installation method as described for Test No.3 in Building Committee Report 1993-4, FPO/CFCA?

· What is the fire rating of the re-roof system/assembly in the manner in which it is to be installed? California law requires the contractor to give the customer a document with this information (Section 13132.7[I] of the California Health and Safety Code).

· What is the weight of the new roof, including the old roof if it is not removed, the wood support system, and any special fire barrier such as gypsum board, cap sheet, insulation, fireblock material, etc., that is required to attain the class roof assembly rating (“A,””B,” or “C”) you want to have installed?

· Does the warranty cover the retention of surface coating for the full term of the warranty, or for some lesser period of time?

Class “C” Installation Class “B” Installation Class “A” Installation

^COMPONENTS	^APP. ^WEIGHT	^COMPONENTS	^APP. ^WEIGHT	^COMPONENTS	^APP. ^WEIGHT
^{Steel panels(1)}	^{150 lbs/sq}	^{Steel panels(1)}	^{150 lbs/sq}	^{Steel panels(1)}	^{150 lbs/sq}
^{Old wood roof(2)}	^{350 lbs/sq}	^{Old wood roof(2)}	^{350 lbs/sq}	^{Old wood roof(2)}	^{350 lbs/sq}
^{Wood support system(3)}	^{60 lbs/sq}	^{Wood support system(3)}	^{60 lbs/sq}	^{Wood support system(3)}	^{60 lbs/sq}
		^{Fireblock material(4)}	^{3.8 lbs/sq}	^{Fireblock material(4)}	^{3.8 lbs/sq}
				^{Gypsum board(4)}	^{170 lbs/sq}
^{Total weight}	^{560 lbs/sq}	^{Total weight}	^{563.8 lbs/sq}	^{Total weight}	^{733.8 lbs/sq}

^{DISCLAIMER: The Committee for Firesafe
Dwellings assumes no liability for the use or misuse of this information, which
is intended to provide guidelines for consumers in their selection of building
materials and fire protection systems for their homes.}

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Please visit: www.firesafedwellings.org for more information.

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