Roofing
Between 1983 and 1996, Dean Kashiwagi surveyed and documented the performance of more than 1,600 SPF roofing systems.In 1998, René Dupuis published resultsof his inspection and evaluation of more than 160 SPFroofing systems in six different climates of the UnitedStates.The surveys conducted by Dupuis and Kashiwagiare very similar in their conclusions that SPF roofing systems are highly sustainable. In Kashiwagi’s 1996 report,the oldest performing SPF roofs were more than 26 yearsold, 97.6% did not leak, 93% had less than 1% deterioration, and 55% were never maintained. Kashiwagi andDupuis also noted the physical properties of the SPF did not diminish over time and that more than 70% of the SPF roofs were applied over existing systems.

Energy Savings
Many large companies and institutions have documented energy savings from the use of SPF roofing systems. Texas A&M calculated the energy consumption of its buildings before and after the application of SPF roofing systems. According to the study of more than eight million square feet of SPF roofing, energy savings paid for the cost of Texas A&M’s SPF roof applications in three to four years. How do SPF roofs so dramatically show results of this type.

According to figures reported by Mike Watts in1996, fasteners alone can reduce the effective insulation value between 1.5% to 31.5%,depending on the number and type of fasteners.Detail 1 shows what happens to a typical roof on a hotsummer day. Dark-color e dmembranes absorb radiant heat. The roof’s surface temperature rises. Ther al bridges such as fasteners and gaps in insulation boards transport the heat within the building.

How does SPF reduce energy costs.

• SPF roofing systems are applied above the roof deck.
• SPF eliminates thermal bridging by providing a continuous layer of insulation over existing thermal bridges in the roof deck and/or roof assembly.
• SPF has a very high aged R-value of between 6 to 7 per inch.
• SPF roofing systems typically are coated with light-colored ,reflective coatings.

SPF roofing systems have exceptional wind uplift resistance. Field observations of SPF performance during Hurricanes Allen, Hugo, and Andrew led the industry to conduct laboratory testing of SPF systems at Underwriters Laboratories and Factory Mutual. SPF’s wind uplift resistance exceeded the capacity of UL’s testing equipment. UL also observed that SPF roofs applied over BUR and metal increased the wind uplift resistance of those roof coverings. Factory Mutual’s testing showed similar results over concrete,metal, and wood.According to Dr. Dupuis and other industry experts such as Thomas Smith and Richard Fricklas, SPF is avery good impact absorbing material. Hail and wind-driven missile damage rarely cause leaks in an SPF roof. The damage typically can be repaired at a later date with-out compromising the long-term performance of the SPF roofing system.One of the most famous examples is the New Orleans Superdome. As evere hailstorm damaged areas of the SPF roof in1978. For the next 10 years, the city debated how best to repair the damaged roof. Finally, in 1992, the roof  was repaired and re-coated. However, prior to the repairs, the roof  never leaked from the hail damage. (Some leaks were reported that were actually caused from bullets fired at the roof during Mardi Gras.)

So to conclude this section, SPF roofing systems demonstrate significant sustainable characteristics. SPF roofing systems have along life, are renewable, save energy, add durability to buildings, control moisture in buildings, and contribute very little to the wastestream. SPF roofing systems greatly reduce tear-offs in many re-roofing projects, which also decreases the amount of materials entering the waste stream.

SECTION 2: INSULATION AND AIR BARRIER SYSTEMS
“Environmental control within a building envelope depends on strong interaction [among] heat, air, and moisture transport collectively." In order to control these factors, there must be “effective air barriers, rain screens, weather barriers, and thermal insulation of a continuous nature so that gaps do not compromise the climatecontrol design."                  

R-Value
SPF’s aged R-value varies, depending on the formulation, type of  blowing agent used, and type of application. Aged R-values of SPF used in insulation and roofing applications with a density SPFR value aging curve ranging from 1-1/2 to 3 lb/ft 3 typically range between 6 and 7.5 per inch.    

Factors affecting the R-value include: thickness of application (the thicker the foam the better the aged R-value), and the substrate and covering systems used (the lower the perm rated covering and substrate, the higher the aged R-value).1 5 Low-density (1/2lb), open-celled SPF typically has a stable, aged R-value ranging from 3.4 to 3.6 per inch (Chart2). In 1997, ORNL performed whole and clear wall testing of SPF between metal stud walls. Three quarters of an inch of high density SPF was applied between studs and 1/2" over the metal studs. Results confirmed that the use of SPF greatly reduces the thermal bridging effect of the metal studs.By controlling moisture infiltration, SPF also provides greater durability to buildings. The number one cause of building deterioration is moisture within the building envelope. Building performance in hurricanes and other catastrophic events can be adversely affected by moisture damage.

Structural Strength
SPF can add structural strength to buildings. Testing conducted by the National Association of Home Builders Research Center showed that SPF insulation between wood and steel stud wall panels increased rack and shear by a factor of 2 to 3 when sprayed onto gypsum board and vinyl siding and increased racking strength 50% when sprayed onto OSB. According to the NAHB Research Center, “During a design racking event (such as a hurricane), there would be less permanent deformation of wall elements and possibly less damage to a structure that was braced with SPF filled walls."Providing a continuous air barrier, preventing moisture infiltration through air leakage, minimizing condensation within the building, avoiding thermal bridging, resisting heat movement in all directions, and providing reliable performance under varying climatic conditions, SPF provides better climate and moisture control.Better climate control saves energy and makes the building more comfortable. Better moisture control reduces building deterioration, increasing the life of the building. SPF’s climate control attribute enables a downsizing of the heating and cooling equipment of a building, further reducing energy use. Side-by-side energy efficiency comparisons have shown up to 40% energy savings by using SPF over the commonly specified insulation materials.The use of high density SPF within the building can add significant structural strength, minimizing damage from building movement and racking events.

Roof mounted HVAC units should be raised and curbed, but
typically don’t require additional counterflashing

The global warming potential of a gas is calculated from its energy absorbing properties over a specified length of time. The longer it takes for a gas to be purged from the atmosphere, the worse its global warming potential. It takes more than 500 years for carbon dioxide emissions to be purged from the atmosphere. Even after 500 years, 19% of carbon dioxide survives to affect global warming. Most HCFC 141b and HFC 245fa blowing agents have left the atmosphere within 10 years.While most roofs are replaced within 15 years, the wall insulation systems typically remain in place until the building is remodeled or demolished. The longer the insulation system remains in place, the more reduction to global warming. SPF roofing systems are not replaced as often, there by increasing their effectiveness in reducing global warming. Utilized as an insulation system, SPF’s ability to provide effective air barriers and control moisture increases its effectiveness in reducing global warming.

SPF and Energy Costs of Production
Franklin and Associates Ltd.’s study,

“Comparative Energy Evaluation of Plastic Products and Their Alternatives for 
the Building and Construction and Transportation Industries," compares the total 
energy requirements for the manufacture of plastic products to the total energy 
requirements for the manufacture of the alternatives. The unique feature of this 
type of analysis is its focus on all the major steps in the manufacture of a 
product, raw material extraction from the earth, fabrication, and even 
transport, rather than a single manufacturing step.The study concludes that 
plastic products in the building and construction industry use less energy from 
all sources than the alternative materials. According to the Franklin and 
Associates’ study, polyurethane foam insulation saved 3.4 trillion BTUs 
in manufacturing energy over fiberglass insulation in 1990. One trillion BTUs 
are equivalent to almost 170,000 barrels of oil and one billion cubic feet of 
natural gas.As mentioned earlier, SPF helps reduce tear-off debris in roofing 
applications. SPF’s on-site application process generates very little debris and 
waste. A typical 10,000 square foot roofing project produces less than 1/2 cubic 
yard of scrap SPF, tape, and plastic(used for masking) and from one pint to 
three gallons of waste solvent (depending on the type of protective covering 
used). Compare this to the typical 10,000-square-foot re-roofing project that 
produces more than 10 yards of construction debris from tear-off and application 
waste. At the present time, so little scrap SPF is produced that recycling of 
the material is not practical.