Gregg Henderson, Skinner, Patricia | 1/16/2007 10:21:53 PM
Homeowners building and restoring homes in South Louisiana should add termite protection during the process.
Both Formosan subterranean termites and native subterranean termites live in nests in the ground. In order to infest wood in a building, they have to move from the soil into the structure through shelter tubes that protect them from exposure to daylight and other elements. Because Formosan termites also can build nest structures in other places if they have wood and moisture available, they are able to survive without returning to the soil
Raising homes on piers offers several benefits for termite detection. To infest a raised structure, the termites must travel up or through the piers or any other objects connecting the building with the ground. Since the underside of a structure built on piers can be completely accessible for inspection, termite shelter tubes can be visible and detected before serious damage has occurred.
Piers made of concrete blocks should be capped by solid concrete, a metal shield, or steel termite mesh to prevent termites from moving from the ground into the building without being seen. Termites can move undetected through the spaces on the inside of concrete block or masonry piers; since solid concrete piers can develop cracks, they should be capped.
Wooden posts treated with creosote can be effective in holding off termites, but eventually the termites may find their way through the insides of the posts. For that reason, wooden posts should be capped, too. Caps don’t prevent termites from entering a house, but the caps cause the termites to expose their shelter tubes for visual identification when they try to get into a building.
Piers and columns in wind and flood zones need strapping, anchors or other connections to resist uplift and prevent floatation. Care must be taken to preserve the barrier provided by the capping device while bridging the barrier with a piece of metal that ties the home (above the barrier) to the foundation (below the barrier). If the strap is visible, it must be examined periodically for termite traffic; if it is concealed, the hole it makes in the barrier much be sealed to the barrier with epoxy.
Corrosion and electrolysis must be considered in choosing the shields and strapping hardware. The metal in the termite shield and the metal in the connector must be compatible. In addition, any metal connectors, termite shields and fasteners should be either double-hot dipped galvanized or stainless steel.
Termite infestations of pier houses can be traced to only a few common entry points in addition to the piers. Any wood-to-ground contact provides an entry point for termites. Any discarded wood or other cellulose products left under the building following construction can provide food for termites. Other entry points include sewage lines, electric conduits and other lines in contact with both the house and the soil. These points should be treated and inspected.