[Termite Control] On The Flip Side

Faith Oi has been dealing with termites for a long time. She’s also been known to say, "In Florida it’s not if but most probably when you will get termites." It happened to her during the 2004 swarm season. Oi is an assistant extension scientist at the University of Florida who performs termite research. Despite her knowledge and expertise, she did not have a termite contract on her home.

After ignoring her problem for about six weeks, an industry friend coaxed her out of her denial that it had finally happened to her. "I finally had to practice what I’ve been preaching," she said. That meant using the appropriate detection technology to locate and isolate the termite infestation and calling in a pest management professional to make recommendations on how to solve the problem.

At the 2004 PestWorld convention, Oi spoke about "how to find and kill termites in difficult construction." She noted that "all construction is difficult because termites hide and are tough to find."

Her home, for instance, is block construction on a slab that had been poured over treated ground. However, a porch addition was built, probably without further treatment, inviting termites to enter the home, tunnel inside the walls and eventually swarm out the roof.

FIRST LINE OF DEFENSE. Detection technologies are helpful in locating live termites, but are only as good as the professional behind the equipment. Nothing can replace a well-trained termite technician. Detection aids specific for termites include visual inspections, which can miss up to 75 percent of the structure; termite-detecting canines, which rely on smell instead of sight; and x-ray cameras. The visual inspection and canines are best for whole room searches, while the x-ray cameras are good for areas where termites are suspected to exist. Technologies that use microwave technology and acoustic emissions are good for verifying a suspected infestation, but have a limited search area.

Oi said she was grateful that these technologies were able to significantly decrease drilling in her home. Termites are not hard to kill, Oi said, especially if you can get the termiticide directly to them. The trick is to find them, and that requires some knowledge of construction types and techniques, termite biology and behavior and the various types of detection technologies available.

Using a large data set gathered by a Florida pest control firm, Oi found that more than 80 percent of termite infestations occur on homes’ exterior foundation walls and through cracks, voids, expansion joints and pipes. Sixteen percent of the homes in the data set were inconclusive for infestation sites based on visual inspections.

WHAT TO LOOK FOR. Forty percent or more of infestations can be traced to the outside foundation walls (OFW), Oi said. Landscaping planted too close to the OFW aids in the termites’ ability to find a house because she thinks the roots act as highways for the termites. While plants and shrubs look pretty against a house, homeowners often unintentionally destroy their home’s termite barrier by digging, mulching and watering around the OFW. Some state building codes now call for all landscaping to be at least 1 foot away from the foundation wall.

Another reason termites infest from the OFW is because rigid foam board has been installed below the soil line. This is particularly problematic in southern states where termite pressure is greatest. Water can be wicked up the wall, creating a conducive condition. Improperly installed wall coverings also can create a conducive condition. Inadequately sized gutters or improperly positioned gutter downspouts also can aid in destroying the termite barrier on the OFW. Gutter downspouts should be directed so that water flows away from the house and dumps at least 1 foot away from the structure. Other problem areas include door frames and walkways, which are poured separately and often go untreated, providing an open pathway for hungry termites. General disruption of treatment areas, such as clutter around a structure, also creates troublesome gaps. There are many other potential causes of termite barrier destruction on building sites, such as digging to bury trash, regrading an area after it has been treated, and leaving roots and stumps under the construction site.

One of the newer trends that troubles Oi the most is the growing popularity of insulated concrete forms (ICFs) used for wall construction. These blocks, often made from recycled materials, are considered environmentally friendly and energy efficient.

One house she described used these forms in combination with a monolithic slab and a steel mesh system, installed by the builder as termite protection. There was a visible inspection gap of at least 6 inches around the perimeter of the slab and the ICFs were not sitting on expansion joints. Oi believed that this structure would probably be sufficiently protected from termites. However, another house she described had the ICFs positioned on a suspended slab, stem-wall construction with rigid foam board insulation installed below grade in an area of known termite activity. She believed that this structure would probably end up with termites.

Oi said she hopes to see termite-protected ICFs in the future. Tests on pesticide-treated foam have already been published in journals and offer some promising results and some builders, she said, are already using effective new plastic barriers impregnated with pyrethroids. They can be used to protect slabs, pipes and other termite vulnerable areas.

THE FUTURE. Despite these advances, Oi said that poor construction and building practices continue to be a problem. Specifically she has concerns about lumber treated with alkaline copper quaternary (ACQ), which appears to be related to corrosion of adjoining aluminum materials, and chlorinated polyvinyl chloride (CPVC) pipes. There were rare instances where the CPVC pipes had bubbled and burst with some builders blaming the pipe failure on termiticide applications. After leaving pipes in concentrated termiticide over two years, the same damage (bubbling) could not be reproduced. She concluded that it was unlikely that a label application of any termiticide could cause a pipe failure similar to what has been seen.

In addition to a good working knowledge of such construction details, Oi gave a brief review of termite digestion, which aids in understanding where and how termites forage. Termites’ primary means of movement involves tunnelling, and the amount of damage to a house depends on the colony’s size, age and vigor. Most of these characteristics cannot be determined accurately for purposes of predicting the age of damage.

In the fight to destroy termites, many pest control companies rely primarily on visual inspections. "But 45 percent of a structure, on average, is not inspectible through visual means only," Oi said. To improve your odds of killing termites, you need to improve the odds of finding termites said Oi, who recommends using multiple detection methods.

Oi is most comfortable with termite-sniffing dogs trained according to the customs-food reward methods because she has the most data to support their efficacy. They are accurate and fast, according to University of Florida research, but training must be maintained. Oi’s group continues to do research on other detection technologies. such as microwave and acoustic devices. Each requires a trained and experienced technician to operate the equipment. "Younger people who have grown up with technology tend to be very comfortable with these new devices," Oi said. "But nothing beats a good pest control professional who uses all of his or her senses to detect a problem area."

The author can be reached via e-mail at jvanklaveren@giemedia.com.