There are only two types of structures in North America: ones that have had termite infestation and the others that will have in time to come. We look for signs of visible evidence of any present or past termite, carpenter ant, carpenter bee, old house borer and or powder post beetle etc in the structure.
Termites are naturally occurring organism in the sub soil for millions of years and there is no effective way to destroy them completely. Subterranean termites are the most common and economically important wood-destroying organisms. Subterranean termites are closely associated with the soil habitat where they excavate a network of tunnels through the soil to reach for water and cellulose. Subterranean termites are social insects that live in colonies that house hundreds of thousands. Termite colony members are dispersed throughout the soil and can extend underground tunnels tens to hundreds of feet to reach feeding sites. In the homes they move through mud tunnels.
The best current practice is to erect a barrier between the house and the soil, and periodic inspection of the components that are normally not seen often. We also check for conditions conducive to infestation in future such as ground to wood contact. Any lumber contact with soil is a potential for WDI infestation. Hence there should be some kind of protection in the form of a barrier (Metal or synthetic shield) between posts, fences, sill plates, trellis, etc. Excessive cellulose deposits (Termites feed on cellulose) close to the foundations like wood mulch or loose wood etc should be kept far away from home. Negative Grading (surface water draining towards house) increases the chances of heavy breeding. Absence of Sun light (Ultra Violet Rays) that normally kills termites, hence they tend to hide in crevices behind the siding, or in very small cracks etc are another sources of concern.
Carpenter ants do not eat wood but excavate wood galleries to rear their young ants and carry aphids to plants, placing them on leaves for the production of honey dew. They feed on (omnivorous) of both plant and animal origin such as plant juices, fresh fruits, insects (living or dead),meats, syrup, honey, jelly, sugar, grease, fat, honey dew (aphid excrement), etc. They eat termites and generally do not co-exist with them in a home. Workers are known to forage for food as far as 100 yards from their nest.
Dry rot is caused by fungus. It is reduced by applying Borates to the area or the removal of the impacted wood.
If any WDII are found, the seller would usually be responsible for treating it before closing. If the home has been treated in the past, the WDII treatment must continue.
The cost of new termite treatment depends upon the size of the home, area to be treated and the difficulty in doing so. The estimates can be $ 800.00 - $ 2,500.00. The cost of maintaining the treatment is $ 125.00 to $ 200.00 per annum.