Causes And Prevention In Subterranean Termite Treatments

Picture this scene: Your firm's sales inspector arrives at the customer's house one morning, responding to a call for a ter mite estimate. The customer greets the inspector at the front door and immedi ately shows him to the kitchen, explaining that is where the infestation is located.

The sales inspector follows the customer inside, identifies the termite problem, and then goes back outside the house to fill out a schematic drawing of the home and the treatment specifications. Then he goes back inside, sells the job, and never inspects the rest of the house. A few days later, the termite technician shows up and treats the structure according to the specifications he was given by the inspector. Sound familiar?

This scenario, says Paul Hardy, senior technical manager for Orkin Pest Control in Atlanta, happens all the time. With situations like this occurring frequently in the pest control industry, it's no wonder many pest control firms have far too many callbacks on their termite jobs, Hardy says. But it doesn't have to be that way.

Hardy has been studying callback and retreat problems for more than 25 years. When he started in the industry, the practice was to treat homes selectively. The use and demise of chlordane, Hardy explained, had something to do with the changes in termite treatment philosophies. For Hardy and his colleagues, treating selectively meant treating all of the spots that were known to be problems: dirt-filled porches, chimneys, plumbing areas, and any areas where pipes went through concrete. When chlordane was taken off the market and labels began to change, Hardy says, attention to those problem areas became diminished. Instead, the emphasis gradually went toward applying the right quantity of chemical and following tighter and tighter label restrictions Based on inspections of callbacks in the field, Hardy has developed a list of six major causes of callbacks and/or retreat-ments:

• Incomplete initial inspection

• Incomplete treatment specifications

• Difficult treatment situations

• Lack of understanding of building construction

• Incomplete initial treatment

• Poor distribution of termiticide

"The ironic thing about it," Hardy said, "is that these six all kind of tie together. One deficiency leads to another deficiency to another deficiency."

INSPECTION AND TREATMENT. Topping the list of callback causes is the situation that occurred in the example above: The initial inspection is incomplete. The problem here, Hardy says, is that inspectors on initial inspections don't know exactly what to look for, and they often miss a critical part of the structure. Hardy calls these "critical entry areas."

One prime example is inside expansion joints; areas where two pieces of concrete are poured together, or where concrete is poured against a foundation wall. Inspectors fail to locate inside expansion joints because they often result from home remodeling where outside foundation walls become interior walls. Such areas get missed because inspectors often do not realize there are expansion joints where outside foundation walls used to be.

Other critical entry areas are step-down or step-up floor levels and raised wood floors, which can hide possible entry points. Hardy points out that every time the floor level changes in a home, there is an expansion joint.

Settlement cracks that have not been located, dirt-filled areas, structural changes, and moisture problems are other critical areas.

The problem of an incomplete initial inspection is compounded when the inspector them writes up incomplete treatment specifications, based on the incomplete initial inspection. The technician can only treat what he or she has the specifications to treat, and in most cases, inspections and treatments are handled by different people.

Incomplete treatments can result if inside support walls are left untreated, or if expansion joints are not vertically drilled.

Often the bath trap area is left untreated, possibly because there is no bath trap access cover to allow for inspection and treatment. When this occurs, technicians should recommend that an access cover be installed. A bath trap access cover allows proper inspection of this area and also allows treatment at the critical area where pipes come through the concrete floor.

Treatment specifications may also omit the treatment of settlement cracks, which are almost always hidden by floor coverings, making visual inspection nearly impossible.

The next area of concern is difficult treatment situations, which translates to a lack of experience in properly diagnosing a difficult situation at the initial and follow-up treatments. Again, some of these situations include floor coverings, raised wood floors, wall coverings, built-in obstructions, such as cabinets or bookcases, and the customer not allowing proper treatment. Often, proper treatment calls for removal of the floor covering or obstruction, which can be a quite complex and costly proposition.

WHERE CONSTRUCTION COMES IN. A lack of understanding of building construction is another area of concern which can lead to an incomplete inspection, as well as incomplete treating specifications. Hardy points out that new construction is more difficult to treat than old construction, and it continues to become more difficult each year.

"That's a weakness," he said. "In all of our training in the pest control industry, we don't teach building construction."

Twenty or 30 years ago, most homes had either simple slab foundations, or were built onto crawlspaces or unfinished basements. But homes today are a combination of slabs and crawls and basements in the same structure, and this can make inspec tion and treatment difficult.

In analyzing retreatments by construction type, Hardy has found that slab construction leads the list, making up more than half of all retreats. Most retreats on slab construction are caused by settlement cracks. Settlement cracks form when the dirt under the poured concrete slab begins to settle. With less support underneath, the slab cracks. Termites then make their way up through the cracks and into the partition walls. In Hardy's observations, monolithic slabs account for about a quarter of all retreats (see charts on page 38).

Crawlspace construction accounts for one-fifth, combination-types for about 17 percent, and basement constructions for about 10 percent. These figures are affected in part, Hardy notes, by the percentage of these construction types in existence. In other words, slab construction may lead the list partly because it is the predominant construction type in the United States, but also because slabs are very difficult to inspect and have more entry points. With crawlspaces, on the other hand, an inspector has the ability to crawl underneath the house and look at the walls. There are less combination constructions in existence than other construction types, but combinations allow more of a structure to be inspected than do slab constructions.

According to Hardy, the No. 1 con tributor of callbacks is stucco below grade level.

Stucco below grade leads to two problems, Hardy says. "One, you can't inspect because you can't see behind the stucco to see if you have termites going up. It also puts wood in direct contact with the ground."

Of course, there are other construction techniques that pose problems for technicians. New concrete slabs have been known to crack the night after being poured. Cable- and-foundation construction, commonly referred to as "post-tension" construction can also present problems. In this construction technique, steel cables are run, criss-crossed across the foundation, concrete is poured over them, and they are tightened after the concrete cures. Technicians can unknowingly damage this type of foundation by drilling into the floor and through the cable, which then must be repaired. Other concerns include foundation insulation outside, foundation wrap inside, wood foundation, and interior water sources.

In many cases the initial treatment is incomplete, and critical areas are missed, which is the next category of concern. Such areas include inside wall expansion joints and voids, leaking shower pans, dirt-filled raised areas, and raised wood floors over slab. Plumbing areas are also commonly missed, such as those in bathrooms, kitchens, air conditioners, or drain lines.

THE CHEMICAL BARRIER. And finally, termiticide distribution is one of the biggest factors pest control professionals must deal with, Hardy said. It becomes a concern when, because of the construction or soil type, the termiticide does not reach the entry areas.

And sometimes, Hardy noted, termiticide doesn't go anywhere close to where the technician thought it would go. For example, clay soil under slabs often won't accept termiticide. Voids under the slab are not reachable. Soil cracking can impede chemical flow, and soil that has moved away from the foundation wall or wet-dry compaction can affect distribution. And, of course, stucco below grade will allow termites to move up between the stucco and the foundation wall, where they will have a ready supply of wood, moisture, and shelter. With such a cozy habitat, they will have no reason to return to the ground, and so will never come in contact with the treated soil. Many times, stucco goes below grade, Hardy explained, because of the grading that must be done on homes to ensure that the land surrounding the structure slopes down and away.

Termite treating is more difficult than it used to be, not only because of construction types, but also because of changes in termiticides, restrictions, environmental concerns, regulations, and lack of experienced operators, Hardy says.

"If a pest control person wants to get a better handle on the retreat problem, what I say is we need to teach ourselves more about building construction," Hardy said. "In other words, the more that a technician knows about how a building is constructed, the better chances that technician has of identifying the critical entry areas and treating them to prevent infestation of termites."

Lisa Josof, a graduate of Northwestern University, is associate editor of Pest Control Technology magazine.