Observations for 2004

• Photo courtesy of CRS Inc., Monroe, N.C.
• Photo courtesy of CRS Inc., Monroe, N.C.
• Photo courtesy of CRS Inc., Monroe, N.C.
• Photo courtesy of CRS Inc., Monroe, N.C.

New developments in roofing materials have brought new installation challenges. Roof systems introduced to the roofing market relatively untested make plenty of room for imaginative installation techniques. It seems market demands generally are oriented to short-term roofing solutions. There remain a few building owners interested in constructing roof systems to provide long-term service (20 years or more), but their ranks appear to be shrinking. In a way, that's good news for the roofing contracting community—Detroit has been at it for years. The name of that game is "planned obsolescence," or we get to replace roof systems more often with more short-term roof system options. As the Gulf Oil dealer says, "Pay me now, or pay me later."

The short-term attitude, the move to more purchasing agents buying roofs at the absolute lowest price and "auction" roof purchasing have caused more than a little consternation for roofing contractors. As the complications created by these methods manifest themselves, we may see a reversal in attitude from end users of roof systems—especially those who own their facilities for the long term. In the meantime, roofing contractors from the "old school" who have been building long-term roof systems with pride throughout the years sooner or later must realize market demands have changed and they must change with the market, change their market or be doomed to extinction. So with more than a little reluctance, we modify our mindset and develop new talent to deal with changing market demands. These observations for your consideration are an attempt to call attention to potential application and business problems and deprive lawyers of at least some of their livelihood. The caveat remains veritable—you get what you pay for in roof systems.

The auction

The bean counters and some roof consulting firms have fostered online roof auctions as an alternative way to buy roof systems. The industry has been part of the auction business for a couple of years now, and the jury still is out as to whether the concept truly is viable for folks who still want long-term roof systems. Some claim to be satisfied with the process; however, fortunate or unfortunate for the purchaser, roof systems don't tend to become serious problems for a few years.

Some contractors have had good experiences with the process; others have dropped out of contention as margins are driven to uncomfortable levels. The process reminds one of the old game of "chicken" as two speeding cars approach head-on with one driver chickening out just before the collision. We all know of auctions where equipment has sold above market value as bidders got caught up in the action of the auction; the same phenomenon occurs as bidders drop prices in the auction process and often wish they had let the bid go to the other guy. After the dust settles, a contractor may not know just what he has bid on or what was included in his bid. That's not a comfortable feeling, especially with high-dollar projects.

On the other hand, there have been some contractors who have enjoyed getting more for a project than they would have had they bid competitively. After a few experiences with the process, contractors tend to bid at prices above what they would otherwise "bid" in a competitive arena. Sometimes, it works out that a job is awarded above the absolute bottom of the successful contractor's tender.

Driving roof system prices lower and lower, the auction process will either result in unacceptable outcomes for the purchaser, more change orders to ensure the contractor has enough money to finish the project or more broke roofing contractors.

What's the bean counters' reaction to that? Simply buy a performance bond. But any building owner who has suffered through that process is not anxious to relive the experience. Time will tell about auctions' viability in the roof system construction process. As long as there are contractors willing to play the game, there will be purchasers willing to take the chance that they can get the desired results for the lowest possible price. To all contenders, good luck.

Wind and wide sheets

Sheet membrane manufacturers are introducing ever-wider sheets in their roof systems in attempts to minimize labor costs for installation and, therefore, be more competitive in the market. It isn't that wider sheets won't work, but some careful attention must be paid to the potential problems inherent in 10- to 12-foot- (3- to 3.6-m-) wide reinforced sheet roof membranes. Aside from the obvious handling problems with rolls, which outweigh the applicators by several times, and potential point-loading effect on roof decks when material for a whole project is stacked all over a roof, wind becomes a major concern.

Although manufacturers can pass current wind-uplift tests at FM Global and Underwriters Laboratories (UL) Inc., the tests don't replicate realistic field conditions. Test panels don't include rooftop penetrations or address typical roof perimeter conditions. The tests are not sufficiently dynamic or of such duration to cause "stretching" of the reinforced sheets caused by relatively continuous and variable wind-uplift pressures in real-world installations. That means suppliers of wide sheet membranes must address these conditions in their specifications—something some do much better than others.

Consider this example: The roof system on a large building in a high-wind-prone geographic area was constructed using mechanically attached 8-foot- (2.4-m-) wide sheet membranes. The roof system included a large number of skylights uniformly distributed over the roof area. Almost from the time of completion, the skylights violently pulled loose from negative wind pressures as to fracture the metal skylight bases in some instances. In some cases, the skylight came up from the wood blocking; in other areas, the wood blocking came up with the skylight flange.

But the major roof system problems came into play when the mechanically secured lap occurred as much as 7 feet (2 m) from the longitudinal side of the skylight units (depending on where the lines of attachment occurred in relation to the location of the skylight units). "Flapping" of the wide expanse of unsecured sheet caused separation of the stripping membranes from the skylight flange, which resulted in leakage at the skylight bases.

Without supplemental attachment of the roof membranes in close proximity to the skylight units, the roof system was contributing to the uplift loads exerted on the skylight units and their ultimate displacement under even moderate wind loads.

You should know that some (if not all) listings for wind uplift on wide-sheet roof systems are based on the use of a Grade "E" steel roof deck in the test. The typical facility with a steel roof deck will not be constructed using a Grade "E" steel roof deck, and, therefore, the listing for the installed roof system will not be valid. It only will make a difference if God decides to place the roof in the adjacent county one day and the lawyers discover the contractor really didn't provide the roof system represented to the owner. Make sure the roof system to be installed is not misrepresented, and under no circumstances assume responsibility for the performance of roof systems or quality of roofing materials provided by manufacturers and/or suppliers.

Dens Deck Prime

In other Professional Roofing articles, I have touted the properties of Dens Deck Prime (manufactured by G-P Gypsum Corp., Atlanta) for cold-adhesive roof system applications and provided some comments about limitations of Dens Deck used in "hot" roof system applications. The smooth, proprietary surface of Dens Deck Prime provides an almost ideal substrate for either bonding adhesives or asphalt-based adhesives used in polymer-modified asphalt roof systems. The bituminous-based adhesives do not become sticky enough during most roof system applications to affect the Prime surface on Dens Deck, and contact adhesives flash off so as to bond only to the adhesive applied to the bottom side of the roof membrane.

But the less-than-obvious problem with Dens Deck Prime used in hot roof system applications is that the asphalt on the wheels of application equipment becomes sticky enough to bond to the Prime surface on the Dens Deck Prime boards, literally rolling the Prime surface up the wheels of application equipment and leaving a denuded gypsum surface with areas of separated facers under the hot-applied roof membrane.

Oiling the wheels on application equipment is not necessarily a good or desirable option for minimizing the problem because of the effects of residual oil in the roof system. The G-P Gypsum recommended solution to the problem when using Dens Deck Prime in hot applications is to place the Prime surface down and apply the roof membrane to the bottom fiberglass mat-reinforced surface of the Dens Deck Prime.

The yet unanswered question is whether the hot adhesive asphalt into which the Prime surface is placed will cause separation of the Prime surface as the gypsum calcines and releases moisture in sufficient quantities to cause separation of the relatively impermeable Prime facer. Perhaps the best solution is to use Dens Deck Prime where it performs best—in adhesive applications—and use regular Dens Deck in hot applications making a provision for the inherent release of moisture when hot asphalt is applied to Dens Deck surfaces.

G-P Gypsum suggests that simply reducing the temperature of the asphalt at the point of application minimizes the calcination (release of moisture) in the gypsum and resultant blistering of the hot-applied roof system installed directly over Dens Deck. That recommendation may help the inevitable, but I still believe the better solution to the potential blistering problem associated with hot roof system applications over Dens Deck is to strip mop a base sheet or use a perforated base sheet. Both application methods allow relatively uniform lateral dispersion of any released moisture into open cavities beneath the base sheet positively minimizing the potential for blistering occurring between the Dens Deck surface and hot-applied membrane roof system.

Dusty surfaces on Dens Deck Prime boards generated during shipping and handling adversely may affect the bonding properties of bonding adhesive and bituminous-based adhesives and become an effective parting agent, making adhesive application a less-than-expedient experience. Even light dusting of gypsum on Dens Deck Prime surfaces will cause adhesion problems of varying severity when self-adhering roof membranes are applied over the dusty Prime surface.

G-P Gypsum reportedly is developing a version of Dens Deck Prime that will have a sealer on all longitudinal factory edges to minimize dust on boards used with self-adhering membrane roof systems. This will cure some dust-related problems, but the panels still must be cut to fit the roof and some dust will be generated during the application process. Removal of field-generated dust on Prime surfaces to which self-adhering roof membranes are to be applied will be imperative to the success of the roof system.

ENERGY STAR®

White reflective roof systems have been the rage during the past couple of years with Chicago at one point insisting all new roof systems installed in the city have a reflectivity value of at least 0.65. This is a strange consideration for a city having at least 10 times (an approximation) more wall area than roof area! But as a concession, the city will settle for "green roofs," another hot roof topic lately. Green roofs will be the topic of another long dissertation.

The Oak Ridge National Laboratory, after spending a few million tax dollars on an "Energy Chamber" that rarely has been used and failing to convince the world that "saturated" insulation in existing roof systems could be dried using unorthodox roofing methods, finally sold a concept to justify its existence to the U.S. Department of Energy (DOE), a federal agency seemingly without purpose.

From the desperation of the agency to survive, the ENERGY STAR concept of reflective roof systems came to be. The U.S. Environmental Protection Agency (EPA) representatives have managed to catch the ear of some politicians and designers and have promoted the ENERGY STAR roof concept. Using smoke and mirrors, imaginary calculations and general hype, the ENERGY STAR concept has opened new markets to suppliers quick to promote the advantages of white/reflective roof systems no matter how flawed the long-term concept. We now have another self-perpetuating myth in the industry. When questioned about the important properties of ENERGY STAR-rated roof systems, the only property important (aside from the fact that insulation also is considered important to energy conservation in roof systems) was reflectance—watertightness and long-term performance of a roof system was of no concern!

White, reflective roof membranes certainly have their advantages for energy conservation (at least in areas of relatively heavy sun load most of the year) but light colors also typically minimize heat damage to roof membranes, increasing their expected service lives. The problem is keeping roof surfaces reflective, and depending on the geographic exposure and how well roof surfaces drain, keeping roof surfaces white can be a significant challenge and major maintenance expenditures for owners of white/reflective roofs sucked into never-never land by EPA hype.

In reality, in northern climates where sun loads are minimal during virtually the entire year, a white/reflective roof system may not contribute to energy conservation at all. In winter conditions, black or dark-surfaced roofs absorb heat, reduce heating loads, and tend to contribute significantly to melting of snow and ice on low-slope roof systems, minimizing the potential for structural collapse. White/reflective roof systems make much less sense in northern climatic areas, but that fact doesn't fit with the DOE existence justification program.

There always will be fungus accumulations in shaded, damp areas of a roof. Fungus growth makes for an "ugly" roof, increases a roof membrane's absorptive properties and discolors the roof membrane surface, therefore raising the roof surface temperature. And some types of fungus live and thrive on polymers included in some sheet membrane roof systems.

White sheet membranes often take on a "negative charge" in the manufacturing process, essentially making them a magnet in attracting positively charged dirt/dust particles. Low-slope roof systems invariably pond water in some areas, which accumulate alluvia remaining as a dark surface after evaporation of water from the roof surface. If you live in the Los Angeles basin, those ponded areas accumulate liquid smog.

In reality, to maintain white roofs in white, reflective conditions will require frequent cleaning of roof surfaces. Frequency of required cleaning varies with geographic exposure and a roof's slope. Even positive slopes do not ensure roof surfaces will be flushed clean by Mother Nature. As I've mentioned before, you get nothin' for nothin' in roof systems. If the attributes of reflectivity are to be a benefit, there will come the inevitable costs of maintaining reflectivity of the roof surface. That will mean regular cleaning, regular restoration of reflective coatings, and regular application of biocides and/or fungicides depending on the type of roof membrane installed. Can the costs of maintaining reflectivity be offset by energy savings? Perhaps, at least in southern areas of the United States.

As roofing contractors, there's no sense trying to bring logic to the world—gear up to provide reflective roof surfaces requested by your customers, and learn the techniques of cleaning various types of roof membrane systems. You should be able to sell at least one cleaning per year to the "believers." At least you probably will not have to participate in an auction to get the work.

UL and FM

There have been some recent rescissions of UL Listings and FM Approvals of composite roof systems, limiting the use of some combinations of rigid roof insulation and roof membrane systems. If you are required to provide a UL-listed roof system or an FM-approved roof system by specification, it would be worth your while to have your supplier certify the system you are proposing complies with current UL or FM roof system criteria. And while you are at it, obtain certification that the roof system has been tested and listed or approved so as to comply with project specifications. Similarly, it would be prudent to request certification from the supplier that the roof system you are proposing meets all the specified fire-resistance and wind-uplift classifications for the type and grade of roof deck over which the roof system is installed.

Withdrawal of UL Listings and FM Approvals may be the result of purging obsolete systems and specifications, a general cleanup of records/files or related to some specific performance issue. Whatever the reason, it should be imperative to ensure the proposed roof system is currently listed or approved by the appropriate testing agency.

Fire and roof insulation

There have been sporadic reports of endothermal reactions in polyisocyanurate foam roof insulation resulting in open burning of the insulation material during shipment and storage. The reaction appears to be limited to thick foam boards (plus or minus 4 inches [102 mm]). Truckloads of thick polyisocyanurate foam have arrived at their destination with smoke pouring from trailers. Open flames break out when shipping containers are opened, allowing the influx of oxygen to the smoldering plastic foam. Some caution should be in order when opening shipping containers exhibiting any sign of smoke.

Some other thoughts

Another year passes as proof of the dynamics of the roofing business. Things never get dull as the industry becomes more complex and demanding. Remember when life was simple? A roof was four plies in coal-tar pitch or asphalt with gravel surfacing. Some of us can remember the good times when it wasn't "how much" but "can you get materials" and "when can you start." All good things must end!

Dick Baxter is president of CRS Inc., Monroe, N.C.