Almost all retailers have seen the latest toy, fad, style, or technology become an overnight sensation and the item that everyone has to have.  Some brands and items stand the test of time while others quickly fade into a distant memory or in isolated cases infamy.  The same is true with the roofing industry as various components and roofing products have become a tried and true standard while others claiming to be the next best thing quickly faded from sight.  The problem is that some roofing components are installed out of sight but unfortunately not out of mind.

The Problem

Phenolic Foam roof insulation was produced by Koppers Company, Inc. from 1981 to 1989 until the Phenolic Foam technology and business was sold to Manville, Inc. who continued to manufacture and sell the product until 1992 when it was discontinued.

Phenolic Foam was specified and sold as a component in numerous low-slope Built-Up and Single Ply Roofing systems as it had one of the highest "R" value ratings for rigid foam insulation, component in numerous low-slope Built-Up and Single Ply Roofing systems as it had one of the highest "R" value ratings for rigid foam insulation, was lightweight, and had excellent heat resistance.  So why did an easy to install insulation with an R value of 8.33/Inch have manufacturers seeing Severely rusted structural decking due to wet phenolic foam insulation. green but building owners ending up seeing red?  The red was rust and premature deck corrosion on structural steel decking which has been found on many of these installations.  The Phenolic Foam roof insulation manufactured in a variety of colors from 1981-1992 used a sulfonic acid as a catalyst in the process of creating the cells of the foam.  While the acid was encapsulated in the insulation after its creation, if the insulation were to become wet or exposed to moisture, the water dissolved the sulfonic acid forming a highly acidic compound.  This compound can quickly corrode and destroy a structural steel deck and other metal components within a roof system.  Unfortunately Phenolic Foam insulation, unlike other closed cell insulations, readily absorbs water just like a sponge.

In many instances building owners and maintenance managers didn't even realize that their Phenolic Foam containing roof system was even leaking.  The super sponge characteristics of the Phenolic Foam absorbed water from the leaking roofing system without any immediate evidence of roof leaks within the building's interior, leading the owner to think his roof was fine.  Unfortunately every drop of water the sponge absorbed was setting off a chemical reaction which was literally eating away at the metal deck. 

In addition to readily absorbing water, Phenolic Foam insulation boards have also been found to shrink over time by as much as an inch or more in width and length.  The gaps create voids which allow for condensation conditions and the absorption of moisture at the edges of the insulation.  Due to these factors, corrosion of steel decking on Phenolic Foam installations is typically found at areas of insulation joints even when the roof system is watertight. 

Steel roof deck corrosion, caused by the wet Phenolic Foam insulation, can lead to catastrophic structural concerns and property damage within a facility as well as personal liability issues with any foot traffic from employees or unsuspecting rooftop vendors.

The Solution

While this doesn't mean that every building owner that has a metal roof deck containing Phenolic Foam within the roofing system needs to start screaming that the sky is falling, they should be concerned.  There have been numerous examples of Phenolic Foam roof assemblies that have shown little or no signs of corrosion to underlying metal decks.  Often these assemblies have had a barrier between the deck and Phenolic Foam which deterred corrosion of the deck, and the roof system has experienced minimal to no water intrusion and has been well maintained.  However, if a building owner believes that Phenolic Foam Insulation exists over a metal deck, caution should be practiced when traversing the roof. 

Building construction and roofing documentation and files should be reviewed by building owners to determine if Phenolic Foam was specified.  If records indicate that Phenolic Foam was used or if rust showing up on the bottom of steel decking leads you to believe that it could be in place, rooftop foot traffic should be restricted until the roof system and deck can be inspected.

Moisture scans such as an Infrared Thermograph can be used to determine potential problem areas in decks by detecting areas of wet insulation.  These areas can then be carefully inspected by taking core samples and inspecting the deck for early or advanced stages of deterioration. 

The degree of metal deck loss to the corrosive nature of the wet Phenolic Foam insulation dictates the extent of repairs that are needed.  In severe cases, deck overlays or complete deck replacement may be required due to structural concerns.  If minor areas of corrosion are found, the corrosive insulation and its residue should be removed from all roofing components and the metal deck thoroughly cleaned and coated with a rust inhibitive paint.  Once repairs are made, an ongoing inspection and maintenance program should be followed to ensure additional damage doesn't occur.

Liability

Class action lawsuit settlements against the manufactures of Phenolic foam roof insulation in the U.S.  have provided building owners with some financial relief  due to metal deck deterioration and subsequent costs associated with it.  The settlements provided 100% of the costs associated with rectifying damage to the metal decks and prorated settlements for roof replacements.  Alert bulletins were issued by the manufacturers of the potentially dangerous nature of Phenolic foam insulation and deadlines were set for the filing of claims against the John's Manville expired December 13 2001.   

While an owner may still have a case for liability against the Manufacturers of Phenolic Foam, they still need to ascertain if the insulation is present within their roof system and what it is doing or has done to the underlying metal deck.  Its up to the building owners to check past construction records for indications that Phenolic Foam insulation may have been used within the roof system. Annual inspections should be conducted to determine roofing components and conditions to help reduce the potentially hazardous affects Phenolic Foam insulation could cause.  After all, ultimate responsibility for a facilities structural integrity and the safety of roof top vendors is placed on the building owner.