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Home | Building Codes | Severe Weather Solution: Hurricane Proof Homes

Severe Weather Solution: Hurricane Proof Homes

Spray Polyurethane Foam Helps Keep Roofs In Place During Major Storms

By Jen Kramer

“You know the phrase, ‘I’m from the government and I’m here to help?’” asks Ed Skvarch, Extension Agent III, Commercial Horticulture with the University of Florida / IFAS Extension, with a chuckle. “Well, for once it is actually true. We really are here to help.”

We are standing in front of the Windstorm Damage Mitigation Training and Demonstration Center located on the sprawling campus of the St. Lucie County Cooperative Extension facility. And Skvarch, the “helpful government worker,” isn’t kidding.

More commonly known as the Hurricane House, the Demonstration Center is one of four such structures built across Florida in the devastating wake of Hurricane Ivan. A joint effort funded by the Florida Department of Insurance with technical support provided by the University of Florida’s Program for Resource Efficient Communities, the Hurricane Houses were designed and constructed in contract with the University of Florida’s Shimberg Center for Affordable Housing at the M.E. Rinker Sr. School of Building Construction. The homes are intended to show Floridians how new construction should be built, and how existing construction can be reinforced, against wind damage.

Hurricane House University of Florida Foamseal

Hurricane House University of Florida Foamseal

In addition to the Hurricane House in St. Lucie, there are Hurricane Homes located in St. Johns, Escambia, and Broward Counties.

The Cooperative Extension program, of which Skvarch is a part, is an arm of the Department of Agriculture and was originally funded to help farmers with their crops – a tradition that is still alive at the St. Lucie branch. “Currently, one of our research projects is the orange blight,” Skvarch says, referencing the citrus bacteria that has attacked Florida’s famed orange groves. But everyone can take advantage of the benefits of their research. “If homeowners have a question about a plant, they can ask us. We are here to help.”

In addition to horticulture, the Cooperative Extension programs include research and information on a wide variety of subjects from food and nutrition to home improvements, energy savings, and wind mitigation – which brings us to the Hurricane Houses.


Engineered to withstand 150-mile-per-hour winds, and roughly 3,000 square feet, each Hurricane House mimics a “typical” one-story, single-family home. Instead of the typical kitchen, bathrooms, and bedrooms, however, the Hurricane House contains a classroom. Transparent panels in the walls cover cut-away sections illustrating examples of wood frame construction and concrete block construction used by Florida builders. These sections show connectors, fasteners, and other types of reinforcing or structural materials that can be incorporated into new construction, or added as a retrofit, in order to increase wind resistance. In addition to the wall cut-aways, the homes teach contractors and homeowners alike how to reinforce and protect openings (skylights, air conditioning units, etc.), protect exterior doors (including garage doors), reinforce roof-to-wall connections, and strengthen the roof deck attachment.

“In order to keep the walls up, it helps to keep the roof on,” says Bruce Bethke, President of Foamseal Hurricane Adhesives. Instrumental to wind mitigation testing and spray foam in Florida, Bethke has joined us at the Hurricane House to explain the role that foam plays. “A house is as strong as it’s weakest link, and that is the shingles. Typically, they can only withstand winds of 110 miles-per-hour, which is where Foamseal comes in.”

In “wind events,” such as hurricanes, roof failure commonly occurs when the strong winds blow perpendicular to the roof’s eaves and overhangs. This creates positive pressure on the roof’s windward side and negative pressure on the other (leeward) side, generating high uplift forces, often causing the roof to fail.

Additionally, roof sheathing installation typically leaves gaps – sometimes varying from 1/8-inch to one-inch wide. These gaps can allow water to seep inside if the shingles or tiles are compromised. “The beauty of Foamseal is that it fills in all of the gaps,” Bethke states, holding up a demo truss that has been sprayed with a fillet of foam. “The Foamseal penetrates into the open areas and bonds the truss to the sheathing. Even if the shingles come off, water isn’t getting in.”

Foamseal® SF2100 Structu-Foam® is a two-component polyurethane system, specifically designed for bonding wood sheeting to roof trusses, as well as for sealing sheathing seams against water intrusion. “The Foamseal works as an adhesive – and as protection from water damage. And it can be applied to new or existing construction,” Bethke explains. The plural-component material is spray-applied onto the joints and seams of the internal roof – not the walls.

Climbing a ladder up to the Hurricane Home’s attic, we see the roof trusses neatly outlined in foam, rather than an attic partially or even completely encapsulated in SPF.

“The foam is sprayed in a stream,” says Bethke, “to create a one-inch by one-inch fillet on both sides of the rafter and at each seam. It is not specifically an insulation foam, but rather is an adhesive foam. We even have a patent – Foamseal Hurricane Adhesive US Patent #5,890,327 entitled Method of Reinforcing the Roof of a Building against Hurricane-Force Winds.”


And it isn’t just Bethke and Skvarch who tout the benefits of spray foam. In a report titled, “Retrofit Techniques Using Adhesives to Resist Wind Uplift in Wood Roofing Systems,” Clemson University’s Department of Civil Engineering published the findings from their testing of Foamseal’s wind uplift resistance. Roofs strengthened with Foamseal were shown to exhibit an increased uplift resistance two to four times over those held together with nails alone.

Applied Research Associates Inc. issued a report, “Analysis of Effectiveness of Foamseal Product in Reducing Losses to Residential Structures,” which found that Foamseal exhibited significant wind- and water-induced loss reduction, by itself (20 to 30 percent) and when used in conjunction with hurricane shutters (55 to 70 percent).

Perhaps the most convincing endorsement comes from REBUILD Florida, a not-for-profit 501 (c)(3) that was established to literally rebuild Florida after Hurricane Ivan. A residential hurricane mitigation program, REBUILD works with the Federal Emergency Management Agency (FEMA) to ensure that Floridians are prepared for hurricanes and other weather-related emergencies. Simply put, REBUILD provides financial and actual assistance in obtaining the structural improvements demonstrated in the Hurricane Houses. Qualified improvements covered under the program include roof deck attachment, reinforcing roof-to-wall connections, gable-end bracing, opening protection (shutters, skylights, etc.), and exterior doors (including attached garage doors).

“People sign up for the REBUILD program,” explains Bethke. “They fill out an application. FEMA funding pays for 75 percent of the improvements, the homeowner pays for 25 percent, and REBUILD takes care of all the work.”

Further, Florida homeowners may be eligible for discounts on their windstorm insurance premium (in addition to FEMA paying 75 percent of the costs of improvement). According to the REBUILD website, documented savings from the discount on annual windstorm premiums range from a few hundred dollars to as much as 50 percent.

Foamseal is proud to be part of the REBUILD program in Florida.

In February of this year, the importance of the REBUILD program, public education, and Foamseal came into sharp focus in Century, Florida. Located in Escambia County in the northwestern corner of Florida’s panhandle, on February 15, 2016, Century was hit by an EF-3 tornado. The winds were clocked at speeds reaching up to 165 miles per hour. In contrast, the same area had been hit by Hurricane Ivan, which had winds ranging from 120 to 130 miles per hour. It is important to note that a tornado’s winds typically exert much stronger force on a house than a hurricane’s.

With a “Strong” rating, the Century tornado traveled a path that was determined to be 16.5 miles long and 300 yards wide, with speeds ranging from 135 to 165 miles per hour. REBUILD had retrofitted 116 homes along the tornado’s path, including the addition of Foamseal to the homes’ attics. Of those 116 homes, 16 took direct hits. Although some of the 16 lost shingles, all survived and remained inhabitable.

As William Merrill, engineer with REBUILD states, “the REBUILD hardened home received no structural damage…I cannot say what would have happened had we not hardened the homes. I can say we added deck adhesive [Editor’s note: Foamseal] to one of the homes and it survived without a problem, yet the similarly built shed next to it that we did not harden lost its roof deck.”

The footage from the aftermath is stark. Foam-enhanced houses stand, while their unprotected neighbors have been reduced to a pile of sticks. REBUILD Northwest Florida has posted the video on their YouTube channel, [click the link on page 52] but it is something that should be broadcast beyond the confines of the Sunshine State. The home improvement techniques employed by REBUILD and demonstrated at the Hurricane Houses are not unique to Florida. Spray foam will save a house in Oklahoma just as it will in Florida. Severe weather, such as tornados and hurricanes, is indiscriminate about geography and state lines. So too is the protection.

“It takes half-a-day to spray the typical house,” Bethke says. When compared with being displaced due to water damage, or worse, losing your home, there is no comparison. “When we started out, we asked ourselves, ‘Can we save lots of lives?’ ‘Can we save tons of property?’ We’ve done approximately 6,000 houses around the state now.”

He continues, “We have saved lives. We’re going to save a whole lot more. At the end of the day that doesn’t feel too bad.”

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