Termite Problems Found During Home Inspections

Termites are social insects with a caste system that includes reproductives, workers and soldiers. Each caste has a unique role in the colony. The soldiers defend the colony against invaders (typically ants) and the reproductives yield new colonies. What makes termites a concern for humans is the worker caste, which bore through wood by digesting cellulose material from structural timbers.

A colony begins when the primary reproductives, also called the king and queen, mate and lay eggs. The eggs hatch into nymphs. The queen determines which caste the nymph will belong to based on the needs of the colony. She then secretes chemicals that transform the nymph into a soldier, worker or reproductive. The termite's type/caste is determined by the secreted chemical.

While there are thousands of different termite species, there are three major species that are of economic significance in the United States…

Subterranean Termites

Subterranean termites are the most common termite in the United States. A mature colony has from 60K to 300K workers. The average colony can consume a one foot length of 2x4 in 118 days. Subterranean termites can enter a home through a crack or void as small as 1/32" in the slab or wall, any lumber in contact with the soil, an earth filled stoop, expansion joints, behind brick veneer, and through rigid foam insulation in contact with the soil.

Subterranean termites have three primary needs: food, which to the Subterranean termite is anything made of cellulose (i.e. wood, cardboard, books); a constant source of moisture, and shelter which is provided to the soil.

Subterranean termite workers are creamy white in appearance and the most plentiful caste in the colony. They forage for food to feed themselves and the rest of the colony. They create tunnels from mud (commonly called shelter tubes) to move above ground.

Subterranean termite reproductives, commonly called swarmers, are the winged members of the colony most commonly seen in the spring when they mate. The entire purpose of the swarmer is to create a new colony. Termite swarmers are often confused with a flying ant. Some common distinctions between the two are: ants have different size wings and few veins whereas a termite swarmer's wings are identical with numerous veins. Ant antennae are elbowed, while termite swarmer antennae are straight. The midsection of the ant is pinched whereas the termite midsection is not.

Subterranean termite soldiers protect the colony against attack. They use their large heads to block holes in the colonies shelter tube and their strong mandibles to crush their enemies.

Formosan Termites

Formosan termites are sometimes called "super termites" due to their ability to cause significant damage in short periods of time. In fact, they are the most destructive wood destroying insect due to their large size and aggressive breeding habits. In fact, a Formosan termite colony can consist of 350 thousand to 2 million workers. Formosan termites are most commonly found in humid coastal and subtropical regions (i.e. Hawaii, South Carolina, Georgia, Florida and Louisiana).

Drywood Termites

Drywood termites feed and nest in wood which has a relatively low moisture content. Unlike Subterranean termites, they do not require any contact with the soil. These termites are usually found in the humid coastal and subtropical regions (i.e. California, Hawaii, Florida, Arizona, South and North Carolina, New Mexico, Texas, Alabama, Mississippi, Louisiana and Puerto Rico). They usually infest attic spaces or exterior wood members exposed to them when they swarm in early spring or summer. Typical evidence of drywood termites include damage, wings, pellets (fecal matter), and entrance/exit holes.

Wood Damage from Subterranean and Formosan Termites

The excavations are only made into the soft part of the wood, giving it a "layered" appearance, and the galleries follow the grain of the wood. They are often packed with mud. The portion of wood exposed to light stay intact, and damage is found by probing and tapping, checking for hollow sounds.

Subterranean Termite Treatment - Chemical Treatment

A chemical treatment is the most common treatment type available for Subterranean termites.

The goal of a Subterranean termite chemical treatment is to establish a continuous termiticide barrier between the termite colony (usually in the soil) and wood in a building. This is done by placing termiticide in the soil on both sides of all foundation elements to provide a barrier preventing termites from entering the structure. Technicians trench the soil and inject termiticide beneath it at 16-inch intervals. They also drill into hollow masonry block foundations and inject termiticide into the block voids. This creates a protective barrier around the property, which is generally good for five years.

Subterranean Termite Treatment - Baiting Systems

In-Ground Baiting Systems are fast becoming a popular method of treatment for subterranean termites. A subterranean termite baiting system involves placement of cellulose (wood material) bait stations at strategic locations around the perimeter of the home. Worker termites - who constantly forage for wood to feed their colony - locate the cellulose bait stations and leave special scent trails to summon their mates to the food source. The cellulose material in the bait station is than replaced with a chemical inhibitor which retards the molting process in termites, preventing them from growing. The carrier termites then bring the chemical back to the colony and - if everything goes well - spread the inhibitor throughout the remainder of the colony. As a result of the growth inhibitor, the carrier and the rest of the colony will die.

Drywood Termites Treatment - Fumigation

If the inspector suspects that a Drywood termite infestation extends into concealed areas, they may suggest a tent fumigation. A fumigation involves placing the entire structure in gas-tight tarpaulin (which resembles a circus tent), releasing the gas inside the seal, and aerating the fumigant. Before fumigation can occur, the homeowner must removal all plants and animals, remove or place food items inside special protective bags, and stay out of the house for a three- day period. While the tent fumigation is more expensive and inconvenient for the homeowner, if done properly, it ensure the elimination all detected and undetected termites in the structure.

Drywood Termite Treatment - Local

If the inspector suspects that the Drywood termite infestation is limited to a small area, he may suggest a borate treatment. This involves drilling small holes in which borates are injected or a local application (spray or foam) at the area of infestation.

Chemical injections are another type of local treatment. This method involves drilling holes into which termiticide is injected. This chemical will remain active in the wood after treatment to thwart resurging colonies.

If a Drywood termite infestation is isolated to a wood member which can be easily replaced or detached, the inspector may simply suggest wood replacement.

If there is any indication that there are galleries leading to adjacent wood members, treatment or removal of those wood members will be required.

Article courtesy of U.S. Inspect.