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Increasing amounts of Destruction

In recent years, the economic consequence of structural damage due to hurricanes has become increasingly evident. This increase in damage can be directly attributed to two factors: increased demand for housing along coastal areas, and the number of inferior strength homes being impacted by these hurricanes. Even the new building codes are only designed to withstand pressures associated with a category 3 hurricane.

The weakest parts of wood construction are the connections holding the wood together. When a roof is built the plywood sheathing is nailed to the rafters creating the structure of the roof. These nails provide the only connections holding the roof together. During a hurricane the winds produce large amounts of suction pulling upwards on the roof. This pressure pulls up on the sheathing prying the nails back out of the rafters. Even if the roof doesn’t fail, each passing hurricane weakens the connections holding the roof together, which increases the chances of failure during future storms. The most efficient way to strengthen the weakest part of a buildings structure is Foam Seal SF2100 Polyurethane Adhesive.

Adhesives in roof protection

Uplift Protection

The structure of a roof is held together by a series of nails connecting the trusses to the sheathing. The continuity of this connection is limited by the spacing of the nail. The most current building codes have increased the frequency of nail connections but there strength is still limited. Adhesives work well in this application since they can be applied in a continuous bead along the length of the rafter, enabling the load to be transferred evenly along the entire length of the roof. When the Foam Seal SF2100 product is applied to the truss and sheathing its uplift resistance is increased up to 5 times stronger then nails alone.

Testing at Clemson University's Civil Engineering Department shows that roof structures can be strengthened to increase uplift resistance from 2 to 4 times the strength of nails alone.

Building Code required nailing patterns should develop sufficient uplift resistance for winds developed in lower category Hurricanes (Category I, II and III). However, if the building envelope is breached, internal pressures can double, thus exceeding sheathing uplift resistance causing a roof failure. History has taught us stronger hurricanes may develop sufficient uplift pressures to remove roof sheathing without window or door failure.

A roof built to the strongest building codes in the country will withstand uplift pressures of 750 pounds to separate the sheathing from the trusses. These uplift pressures are associated with a medium strength hurricane, so the chances of roof failure go up considerably in higher strength storms. Testing shows if the envelop of the building is breached pressures will instantly double increasing the uplift pressures trying to pull the roof off. In our uplift video the same roof with Foam Seal SF2100 will test over 3,000 pounds of pressure to separate the structure of the roof.

Water Intrusion

Foam Seal is sprayed on as a liquid quickly hardens into a water tight seal. This reduces water intrusion by 99% even if the roof covering is removed. Foam Seal Hurricane Adhesive is a PATENTED moisture sealing foamed polyurethane sheathing adhesive.  The sheathing of built to code roofs are connected by brackets that create a separation of 1/8” to 1/4” between every piece of sheathing. A 4,000 square foot building can have approximately 200 sheets of sheathing. If you add up the open spaces between all of the sheathing there will be over 33 square feet that is completely left open. That is the equivalent of 1.5 sheets of plywood missing.

When built to code roof sheathing is installed with a 1/8" to 1/4" space at the seams. Therefore, this leaves gaps of 12 to 24 square inches per 4x8 sheet of sheathing. A 4,000 square foot building can have approximately 200 sheets of sheathing; thus, a fully exposed roof deck could have up to 33 square feet of open space for water to enter the building. This is the equivalent of 1 full sheet of plywood missing.

Testing at ITW Foam Seal's Technical Center shows that the application of Foam Seal Hurricane Adhesive to the sheathing seams reduces water intrusion considerable. Roof coverings (shingles and tile) are usually the first things to fail in high winds like those experienced during hurricanes. Once the roof covering is damaged water will easily pour into the attic through these open gaps now exposed. With Foam Seal SF2100 there will be no need for costly mold removal or a fashionable blue tarp to be placed over your roof after a storm of high wind event.

If the roof covering is blown off the roof or even slightly damaged there is nothing to stop the water from pouring into the house. Roof coverings (shingles or tile) are usually the first thing to start failing in a high wind event. The closed-cell Foam Seal product will create a water tight barrier between all of the pieces of sheathing. This will keep the water from entering the attic through the gaps, eliminating the possibility for dangerous and costly mold spores to grow and spread. Foam Seal hurricane Adhesive is your last line of defense when the roof covering is damaged during a hurricane.