Industrial / Commercial - Building Restoration, Renewal, and Spray Polyurethane Foam Insulation Specialists

SPF vs. Hurricane Hugo

The Roofing System That Can Stand Up to High-Wind Disasters
"The application of Sprayed foam to steel deck and plywood deck demonstrated uplift load resistance up to the capacity of the test equipment to develop load (160-165 psf) without any sign of delamination or other damage to the foam." --Underwriters Laboratories, Inc.

Roof on left is missing 1/4 metal

Sprayed polyurethane foam roof resists wind uplift

These two buildings in Puerto Rico are located just a few yards apart, so they both received the same degree of wind force when Hurricane Hugo stormed over the island. The building on the left received major damage as wind uplift ripped off a portion of the roof. The building on the right has a sprayed polyurethane foam roof which held tight. There was no peeling, penetration or water leakage. Polyurethane foam is self-flashing--it forms a seal that grips the building wall and roof-mounted equipment so there are no edges for the wind to lift up and peel away.

  • Save Life, Limbs and property when disaster strikes
  • A sealed envelope of protection from destructive winds
  • Prevent costly water damage
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Foam Church after TornadoThis church survived the tornado that cut a path of destruction through Plainfield, Illinois. The building was completely covered in sprayed polyurethane foam. There was repairable missile damage to the exterior surface, yet the sealed polyurethane foam helped to strengthen the building and resist uplift from the high-force winds. Because polyurethane foam is spray-applied, it can conform to any shape and provide a sealed envelope of protection.

SPF vs Hurricane Andrew

SPF roofing holds it together during hurricane-force storms

Ten years ago, Hurricane Andrew wrought unprecedented economic devastation on the northwestern Bahamas, the southern Florida peninsula and south central Louisiana. According to the National Hurricane Center, the hurricane caused more than $26 billion damage in the United States. Before Sept. 11, Hurricane Andrew was the most expensive disaster in U.S. history.

The insurance industry identifies roofing as the primary contributor to disaster-related insured losses. The roof and exterior glass are the most vulnerable parts of the building envelope in any wind event. Because a damaged roof can expose the building’s interior — and its inhabitants — to the storm’s wrath, the total cost of a roof blow-off can rise as quickly as the storm’s own momentum.

Since Andrew’s devastation, many materials manufacturers and members of the roofing industry, along with members of the insurance industry, code officials, architects and consultants, have invested countless dollars and hours identifying ways to mitigate the damage caused by roof failure during wind events.

The reason for roof failure can often be found in the very design of membrane roof systems. Wind often grabs the edge flashing or coping and peels back portions of the membrane.

In comparison, spray polyurethane foam has gained recognition with industry experts for its ability to withstand high wind uplift and blow-off because its smooth, continuous surface grips the deck and walls. It offers superior adhesion with no need for fasteners and there are no joints or edges for the wind to grab onto. Lightweight yet rigid, it provides extra strength to help the roof stand up to the forces of nature.

“SPF has tenacious adhesion and there’s no way it will ever blow off,” says Richard Fricklas, founding father and former technical director of the Roofing Industry Educational Institute. “It sticks to anything with very high pull-off strength. The minimum strength of SPF would be about 10 pounds per square inch and most blow-offs concern pounds per square foot. Even if the blow-off strength was only 1 pound per square inch, by the time you multiply it by 144 square inches in a square foot, that would still be 144 pounds per square foot of wind uplift resistance.”

Field Studies
Hurricane Andrew struck southern Dade County, Fla., especially hard, with violent winds characteristic of a Category 4 hurricane on the Saffir/Simpson Hurricane Scale. In Dade County alone, the forces of Andrew resulted in 15 deaths and up to 250,000 people were left temporarily homeless. An additional 25 lives were lost in Dade County from the indirect effects of Andrew.

When it was over, Thomas L. Smith of TLSmith Consulting, and then research director for the National Roofing Contractors Association, went to Florida to see first-hand how SPF had weathered the storm.

“Two things stood out in my mind after my field studies — one was SPF’s adhesion and the other its ability to accommodate wind-born debris or ‘missiles,’” Smith reports. “A missile will tear into or gouge out the foam, but the roof will not leak. Typically there are a lot of missiles flying around during a hurricane, so that’s a significant advantage.”

In his published report of his findings post-Andrew, Smith provides a detailed assessment of the wind performance of 11 SPF roofs. Three of the buildings were in areas of very high winds, one in an area of high winds and seven in areas of moderately high winds.

Two of the three roofs in the very high wind zones were SPF over old BUR; the third was SPF over thin-shell concrete. Two of the three roofs sustained minor damage from missiles. One of the SPF-over-BUR roofs experienced peeling that did not progress beyond an area of missile impact.

“Often foam is applied over existing roof coverings and I did see a number of buildings in South Florida where this was the case,” says Smith. “If the underlying roof is weak and it lifts up, it will take the SPF with it. But it appeared to me, although it’s difficult to quantify, that the foam acted as a stiffener, so when the original roof lifted up the failure did not propagate as far into the field of the roof. You might have a corner peeled back, but the corner area would be limited because of the stiffening influence of the foam. Had the foam not been applied there, I think the roof failure would’ve been much larger. I feel very strongly about that, but it is very hard to quantify.”

Other buildings with traditional roofing systems in a 200-foot radius surrounding the SPF-over-BUR roof that peeled suffered significant damage, including gable-end wall failure and collapsed trusses, as well as blown-off sheathing panels and asphalt shingles. One building had reportedly had its BUR blown off.

Smith says that if SPF is going to fail during a wind event, it is because the surface it has been applied to has failed. “Typically, the foam is not going to lift unless whatever it is sprayed to lifts,” he says. “If the deck itself is not adequately attached, everything above it could just come off the supporting joists or beams, so that would be one failure mode. It could also fail if an element between the deck and the foam doesn’t have good adhesion or if the SPF is applied to an existing membrane that is not adequately attached.”

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Latham, NY

When Ford's corporate facilities people approved a new roof for the firm's Latham, NY Tractor Division depot, they did so to solve a long-term problem resulting from long-term deterioration of the original tar-and-gravel built-up roof.

   What they got, in addition to the ultimate solution to that leakage problem, was an energy-saving system that in effect would help pay for the new roof over a period of years.

   The 104,000 sq. ft. building is heated by natural gas.  After installation of the GE silicone roof in October 1977, an analysis of natural gas use indicated  16% reduction in 1978, attributed to the new roof.

   According to roof Plant Manager, Lew Phillips, the General Electric Company's silicone roof system was selected after evaluation of several elastomeric membrane systems, because it promised singular advantages in terms of life, ease and speed of application and water resistance.

"...a silicone roof system was selected...because it promised singular advantages in terms of works life, ease and speed off application, and water resistance..."

"What we didn't count on," said Phillips, "were the unbelievable fuel economies we realized once the new roof was in place."
Urethane base

   These economies have resulted from the unique design of the General Electric roof system which, in this case, decreased the topside's U factor. After thorough cleaning and spot repair at Ford's existing built-up-roof, urethane foam was spray-coated on the old surface to a depth of 1". Two coats of weather-resistant silicone rubber were then sprayed on the urethane base, forming a tight homogeneous shield that resists not only moisture penetration, but the deteriorating effects of ultra-violet as well.

"General Electric's Qualified Applicator, S.D. Carruthers Sons, Inc., got the total job done -- that's 104,000 sq. ft. of roof -- in just four days, once surface preparation was complete, " added Phillips. "Facility maintenance has been reduced because there are no more leakage problems and the place is much cooler in summer. What more can you ask?

Information courtesy General Electric Co., Silicone Products Division, Waterford, NY 12188

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Climate Control Division
Ford Motor Company

Energy Shield, Inc.
138 W. Pike Street Pontiac, Michigan 48341-1747

Sheldon Road Plant
14425 Sheldon Road
Plymouth, MI 48170

April 27, 1994

RE: Polyurethane Sprayfoam Re-Roofing by Energy Shield, Inc.

To Whom it may concern:

    In 1990 we elected to re-roof our Sheldon Road plant and administration building in Plymouth, Michigan, and Energy Shield was selected to be the contractor by competitive bidding. The scope of the work involved installing a new sprayfoam roof to approximately 900,000 square feet of roof area at a total cost to us of in excess of $2,000,000. Additional building insulation work was done in 1991 and 1992 by applying sprayfoam to selected wall areas.

    The installation of the work was completed in a timely fashion and with good workmanship. We are especially pleased with the trouble-free performance of the new sprayfoam roof system and the dependable follow-up service provided by Energy Shield.

    Prior to the application of the sprayfoam roofing system our plant had a 25 year old "BUR Roof System" and we were spending approximately $80,000 annually doing small repairs to the existing roof. In addition, the areas above our aluminum radiator furnaces were experiencing extreme cold and hot spots which was causing as much as 6" to 8" of movement of the roofing materials in different directions and this caused many leaks.

    The polyurethane sprayfoam roof system can be applied directly to old BUR systems and in most cases, such as ours was, total tearoff of the BUR and can be eliminated with a moisture study of the roof so as to remove only the wet areas. Thus the substantial costs of total roof tear-off and disposal can be eliminated. Another benefit of the sprayfoam system that we noticed was the reduction in our energy consumption. At the Sheldon Road Plant, we realized a decrease in our energy bills from $876,000 annually to about $412,000.

    We are very satisfied with our sprayfoam roof and haven't experienced any problems or maintenance costs since the installation. It is a cost effective way to re-roof and insulate your building.

    Regards, signature.jpg (6809 bytes)

M. M. Forester, Plant Engineer
Technical Services

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Information courtesy General Electric Co., Silicone Products Division, Waterford, NY 12188

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Tel: (319) 223-5137